I/O Shield access • Install and learn the basics of Rebol now!
Year One Issue #2 Feb 2014
ODROIDMagazine Turn your ODROID into a: Giant Tablet And create the ultimate Android experience!
High Performance computing at home • Meet an Odroidian Creation and fine granular control Mauro Ribeiro, Senior Software engineer • Estimating Radio net interference: Using Java mutithreading • Linux Gaming - emulators
• Start programming right away! • The art of multi boxing
• USB Gadget drivers • 811.02ac router with odroid XU Dominate your device ports to do everything Get up to 433mbit/sec
EDITORIAL
service to the world-wide ODROID and Open Source communities, Hard Kernel is proud to present its newest contribution to ARM technology: A ODROID Magazine, a free monthly PDF e-zine! This cutting-edge online publication brings you the latest ODROID news, as well as featured articles from the expert community that has grown around the amaz- ing ODROID family of micro-powerhouse computers. Intended for all levels of expertise from beginner to guru, ODROID Magazine features definitive guides for new owners, with easy-to-follow steps in setting up your ODROID, installing operating systems and software, and troubleshooting common issues. For more technical users, each month will feature expert tips, hacker discus- sions, cutting-edge projects, and technical articles to explore new ways of making your ODROID even more versatile. Hard Kernel’s ODROID Magazine is an ideal opportunity for our community to come together to share and contribute articles, so that everyone can be successful with their ODROID. Each month, a series of article topics will be posted for consideration, and all community members are encouraged to send submissions in exchange for monthly rewards for those selected for publication. The best articles are those that walk the reader through complex concepts and procedures in a simple-to-read format. At least one picture or graphic per article is required, and should be between 500-2000 words. In this issue, we show you how to turn your ODROID into an enormous 42” touchscreen Android tablet, suitable for kiosks, digital signage, gaming, accessibility, and just plain fun. You’ve never played Fruit Ninja like this!
ODROIDMagazine
Rob Roy, Chief Editor Bo Lechnowsky, Editor Bruno Doiche, Art Editor
I am a computer programmer living I am President of Respectech, Inc., a Spent his last vacation doing nothing. and working in Silicon Valley, CA, technology consultancy in Ukiah, CA, And didn’t manage to do the half of it. USA, designing and building websites USA that I founded in 2001. From my such as Vevo, Hi5, Dolby Laboratories background in electronics and com- and Hyundai. My primary languages puter programming, I manage a team are jQuery, Angular JS and HTML5/ of technologists, plus develop custom CSS3. I also develop pre-built operat- solutions for companies ranging from ing systems, custom kernels and opti- small businesses to worldwide corpora- mized applications for the ODROID tions. ODROIDs are one of the weap- platform based on Hardkernel’s official ons in my arsenal for tackling these releases, for which I have won several projects. My favorite development Monthly Forum Awards. I own a lot of languages are Rebol and Red, both of ODROIDs, which I use for a variety of which run fabulously on ARM-based purposes, including media center, web systems like the ODROID-U2. I have server, application development work- deep experience with many unique op- station, and gaming console. erating systems.
ODROID Magazine, published monthly at http://magazine.odroid.com, is your source for all things ODROIDian. • Hard Kernel, Ltd. • 704 Anyang K-Center, Gwanyang, Dongan, Anyang, Gyeonggi, South Korea, 431-815 • Makers of the ODROID family of quad-core development boards and the world’s first ARM big.LITTLE architecture based single board computer. Join the ODROID community with members from over 135 countries, at http://forum.odroid.com, and explore the new technologies offered by Hardkernel at http://www.hardkernel.com.
ODROID MAGAZINE 3 ODROID MAGAZINE 3 Converting a Monitor to a Giant Android Tablet Justin Lee and Charles Park
ouch screens are common in devices also more expensive, especially when An infrared touch screen uses an array such as smartphones, game con- the screen size is larger than 20 inches. of X-Y infrared LED and photodetector Tsoles, all-in-one computers and tab- A capacitive screen can only be acti- pairs around the edges of the screen to lets. They also play a prominent role in the vated with an exposed finger (no gloves detect a disruption in the pattern of LED design of digital appliances such as digital or pointers), and can experience opera- beams. These LED beams cross each signage, Point of Sale (POS) systems, sat- tional difficulties if the monitor is not other in vertical and horizontal patterns, ellite navigation devices, mobile phones, correctly mounted into a metal housing which helps the sensors pick up the exact video games and some e-books. due to the electrical field. Considering location of the touch. A major benefit of The Android OS, one of the main its ease of use and lower cost, the infra- the infrared system is that it can detect operating systems for the ODROID, red-type touch screen is better suited for essentially any input, including a finger, has an intuitive user interface designed this project. gloved finger, stylus or pen. It is gener- for use with a touch screen. This article ally used in outdoor applications and describes how to use an ODROID to Infrared(IR) Grid point of sale systems which cannot rely change any monitor or TV into a giant touch screens on a conductor (such as a bare finger) to Android tablet. activate the touch screen. Unlike capacitive touch screens, in- Infrared vs frared touch screens do not require any Capacitive touch patterning on the glass, which increas- screen es durability and optical clarity of the overall system. However, infrared touch Touch screens primarily use either screens are sensitive to dirt and dust that infrared or capacitive technology. Ca- can interfere with the IR beams, and pacitive touch screens are more popu- suffer from parallax in curved surfaces lar for smartphones and tablets, but are Principle of IR (Infrared) touch screen and accidental touch notifications if
ODROID MAGAZINE 4 MAKE YOUR GIANT ANDROID TABLET the user hovers his/her finger over the & Play. of VID:1870, PID:0119 appeared to screen while searching for the item to It’s important to check whether the represent a touch screen from Nexio Co., be selected. touch screen is really Windows 8 com- Ltd. Other touch screens will report dif- patible or not. True ferent VID, PID and vendor informa- Plug & Play devices tion. do not require a separate driver to be Step 2: Modify installed on a Win- hid-ids.h and hid- dows PC. If the multitouch.c touch screen needs a specific device driv- After downloading the appropriate er, it is not natively Android kernel source from dn.odroid. compatible with com, navigate to the kernels/drivers/hid/ Windows 8 and will be less likely to work with Android. Principle of IR (Infrared) Multi-touch screen
How to Choose an There are 4 steps to using the touch Infrared touch screen screen with the Android OS in a You can make your own touch screen nutshell: Example PID and VID values added to by following guides found on the Inter- kernels/drivers/hid/hid-ids.h 1) Get the Vendor ID and Product ID from the net, but it is not easy to implement the touch screen USB interface. complex multi-touch algorithm and well 2)Modify the files hid-ids.h and hid- directory, then add the VID and PID to aligned IR emitter/receiver pairs. multitouch.c, both located in kernel/drivers/ the end of the hid-ids.h header file. Before purchasing an infrared touch hid/ Also, add the new ID in the hid- screen, it’s important to evaluate its com- 3) Build the kernel with the HID-MULTITOUCH multitouch.c source file. It must be patibility with Android. It must meet at option enabled, and transfer the kernel image least one of the following requirements: to the ODROID. 4) Create an IDC (Input Device Configuration) 1) Is your touch screen listed in the Linux file. multi-touch compatibility table? http://lii-enac.fr/en/ar- chitecture/linux-input/ Step 1: Check the multitouch-devices.html VID and PID If yes, it will be very easy to activate your touch screen. Plug the touch screen into any Linux PC, then find the VID and PID by typ- 2) Is your touch screen Windows 8 compatible? ing lsusb in the terminal as below right. If yes, you need to add a few lines in the Kernel To determine which device entry Example of adding the touch screen ID to driver and an input configuration file. is associated with the touch screen, list kernels/drivers/hid/ the devices before connecting the touch hid-multitouch.c 3) Does your touch screen manufacturer sup- screen, then list them again after con- ply specific Android driver source code? If yes, you need to follow their porting in- necting it. The new entry will cor- struction. respond to the touch screen device. During our project, when the A touch screen which meets the first 23-inch touch screen was con- requirement was not available in our lo- nected, an entry of VID:03FC, cal Korean or Chinese markets. Some PID:05D8 appeared in the de- touch screen manufacturers in China vice list, which represents a touch offered to supply the driver source code screen made by Elitegroup Com- for their products, but the sample code puter Systems. With the 42-inch was not useful in the real world. The best touch screen connected, an entry alternative was a touch screen that sup- Reading the VID and PID of the USB ported Windows 8 HID-compliant Plug touchscreen using a Linux PC
ODROID MAGAZINE 5 MAKE YOUR GIANT ODROID TABLET placed in the hid_device_id mt_devices via fastboot protocol in u-boot. Carefully attach the touch screen to structure define. align the viewing window. Step 4: Create an Step 3: Build the IDC (Input Device kernel with the HID- Configuration) file MULTITOUCH option enabled If you don’t make a proper IDC file, the resolution of the touch screen will not Type “make menuconfig” to config- match the HDMI resolution. Create a ure the kernel, then go to plain text file as below: Device Drivers > HID Devices > Special HID drivers > HID touch.deviceType = touch- Screen Testing the touch screen - 6 points guarantee touch.orientationAware = 1 the sensor integration with the software. device.internal = 1 keyboard.layout = qwerty Test the touch screen. Our touch keyboard.characterMap = qwer- ty2 screen could detect up to 6 points. keyboard.orientationAware = This smaller 23-inch touch screen 1 keyboard.builtIn = 1cursor. mode = navigation cursor.orientationAware = 1
Configuring the touch screen with an embed- The file name must beVendor_xxxx_ ded driver in the kernel configuration. Product_yyyy.idc (xxxx: Vendor ID, yyyy: Device ID). I made two Multitouch panels and select it as files for Elitegroup and Nexio. The filename an embedded driver (*), as seen below. is case sensitive. Then, set another two options as an em- bedded driver, indicated with an asterisk (*) Vendor_03fc_Product_05d8.idc 23-inch touch screen panel with velcro belts playing Fruit Ninja on Android. Device Drivers > Input de- and Vendor_1870_Product_0119.idc vice support > touch screens > USB touch screen Driver Copy the IDC files to your ODROID and: with the below commands. Device Drivers > Input de- vice support > touch screens > adb remount adb push Vendor_03fc_ Product_05d8.idc /system/ usr/idc/. adb push Vendor_1870_ Product_0119.idc /system/ usr/idc/. adb reboot panel came with 4 velcro belts and it was relatively easy to assemble. How to Attach the Besides gaming and personal use, the 42-inch Touch Panel ODROID is ideal as the core computing to the TV Screen. device for kiosks, digital signage, human Configuring the touch screen with an embed- interface research, and more, because of its ded driver in the kernel configuration high performance computing power, rela- tively low cost, and open platform which al- GeneralTouch touch screen de- lows modifications such as this touch screen. vice support A video is at http://www.youtube. Save the Kernel configuration and com/watch?v=HDsnuxchxtU, and for compile it to make a zImage. Preparing the touch screen: Attaching the more giant action, http://www.you- Transfer the zImage to your ODROID double-sided tape to the touch screen frame tube.com/watch?v=n8_cV_NeWQ8.
ODROID MAGAZINE 6 INSTALLING ANDROID ON AN ODROID Installing android on an ODROID the Mad Scientist chronicles continue Bohdan Lechnowsky
his moment finds you in your fa- issue of ODROID Magazine. Handily, miliar laboratory, hunched over you printed out and bound the entire Check that your OS your lab counter, illuminated by last issue of ODROID Magazine for easy T version is higher than the soft glow of your plasma display, net- reference. Sometimes, it’s just nice to work indicator lights, catalyzing chemi- feel paper between your fingers. Beta 1.6 cals in various test tubes, and such. Be- After a few cobbled attempts at down- (Settings > System > About fore you lays a brand new ODROID-U3 loading the latest Android release for the Tablet) which you are in the process of modi- ODROID, you actually slow down and fying into a combination superphone/ study the proper way to do it. The Build Number has a date code, world-domination device. As the U3 is – for most intents and and should be April-2013 or later. This On another ODROID inches to your purposes – identical to the U2, you fol- image is 24-April-2013. right plays an inspiring YouTube video of low the procedures for installation on the The Ben Heck Show while you hack old U2. You find the latest full version of Download the Android update file. IDE ribbon cables and connect your U3 Android for the U2 is the Android Beta Visit http://dn.odroid.com/An- to various items on your worktop like 1.6, and the newer versions are simply droid_Beta_1.8.0/U2/ (for other batteries and miniature displays. updates to that version. models of ODROID, leave off the “U2” Upon completing the last solder con- You download Android_Beta_1.6 at the end). Select the SD or eMMC image, depending on the card that you nection, you look up with a menacing for the U2 from http://dn.odroid. have installed, and start the download. smile of accomplishment and say, “Flip com/Android_Beta_1.6/U2/ and the switch!” After a brief moment of write it to your SD/eMMC card as Create the updater directory. inactivity, you remember that you still explained in the January 2014 issue Create the directory /sdcard/up- don’t have a lab minion. Not only that, of ODROID Magazine. Once it has dater using File Explorer that should be but there is no switch to flip. However, completed, you plug the card into your included in your Apps list. there is an on/off button on the U3! ODROID and yell, “PUSH THE BUT- You power on your U3, but then real- TON!”, this time remembering that you Move the update file to the updater ize after another brief moment of inac- have neither a minion nor a flippy-type folder. tivity that you don’t have an OS on your switch. You catch yourself cackling in glee Copy the downloaded .zip file con- SD or eMMC card. You decide that you as the ANDROID logo appears across taining the Android Beta into the /sd- should probably install Android as it is your mini display connected to your U3. card/updater folder. - the best choice for the superphone por You find instructions for updating Start the update process. tion of your invention, and you can run to a newer version of Android on the Linux in parallel with Android for the odroid.com blog, and you make some (Settings > About Tablet > world-domination half of your inven- changes to bring it up to the current ver- ODROID ) tion, as explained in the January 2014 sion, like so:
ODROID MAGAZINE 7 HPC AT HOME High Performance Computing AT Home compute like you never did before Cooper Filby and Anthony Skjellum - Runtime Computing Solutions LLC
n the previous issue of ODROID Installing the Magazine, we discussed the ben- Operating System I efits of using ODROIDs for High Performance Computing (HPC), in There are a number of prebuilt Linux addition to various discoveries while operating systems available for ODROID working with XU+E’s related to set- boards from http://dn.odroid.in. To get If this doesn’t make you want to make a Voltron ting up our own cluster in a commer- started, download the Ubuntu Server based cluster using five ODROIDs, we cannot cial setting. But what about the home image for your ODROID model and ex- be held responsible for the giant robots that user that wants to experiment with tract the .IMG.XZ archived image using may someday take over your hometown. HPC? In part one of this multi-part an archiving tool such as 7zip on win- series, we outline the setup and con- dows, or by typing “xz” from the Linux them nodes for simplicity from now on) figuration of a basic “headless” cluster command line. Finally, you can copy via the ssh protocol using Terminal (or with the end goal of running parallel to the medium of your choice, such as Putty if running Windows) in order to programs based on message passing, an SD card or an eMMC module, us- continue setting up our cluster. Because using the Message Passing Interface ing the “dd” command on Linux/OS of potential initial hostname and MAC (MPI) parallel programming model in X systems or the Win32DiskImager.exe address conflicts that we will resolve in particular. for ODROID on Windows. For more the next section, we will need to boot the In subsequent articles, we plan to detailed instructions on copying over first ODROID and set a few settings be- expand on this setup to build a cluster the OS, please refer to Bohdan Lech- fore starting the second. with a centralized head system or node, nowsky’s article titled “Installing an OS complete with services such as Puppet, on an ODROID” from the January [Editor’s Note: If one is available, a de- NFS, and LDAP, a configuration that 2014 issue of ODROID Magazine. We velopment machine running Linux or is capable of supporting a much larger recommend using the eMMC modules Windows is recommended to more easily number of ODROID systems (nodes) available from Hardkernel for better per- setup and reboot the cluster, troubleshoot configured as an HPC cluster. For ex- formance, but SD cards work well too. hardware problems, and other necessary ample, in part two, we will cover basic debugging. An alternative to using a networking configuration of the head Connecting to your separate computer is to plug a USB key- node, including dnsmasq, NAT, and Odroid and User board and HDMI cable into the first adding more nodes to the cluster, while Configuration ODROID and use it directly to boot- in part three (and further installments), Since we opted to use the Ubuntu strap the cluster instead of via SSH as de- we will cover additional services such Server image for our ODROIDs, we can scribed in the next few paragraphs. Press as LDAP, NFS, Autofs and Puppet. connect to our XU-E systems (we’ll call Ctrl-Alt-F1 to use the framebuffer con-
ODROID MAGAZINE 8 HPC AT HOME
to the router’s admin panel, you can also name. You can use other names of your make use of the nmap command to choice; they have to be unique to each scan your network for hosts to find node. the ODROIDs, if you know your The MAC address conflict was a sub- network information. For ex- tle issue that we encountered when we ample: “nmap 192.168.1.0/24”. first set up multiple ODROID XU+E’s. Look for a host that has port 22 We found that, by default, the onboard open. ethernet devices all shared the same Power on one of the MAC address, which made it impossible ODROIDs, then enter “ssh to work on a single ODROID if mul- odroid@ubuntu-server” (or tiple were powered online and on the “ssh [email protected]”, same network. If the two ODROIDs if using the IP address) in the you’re working have identical MAC ad- Terminal or Putty window of dresses, there are two straightforward the host computer, which will ways to resolve this: 1) configure one (or establish a secure connection to both) of the ODROIDs to use a different the ODROID. To login, type MACaddress, or 2) setup USB ethernet “odroid” as the password. dongles, which should all have unique Once the command prompt ap- MAC addresses. The specific values you pears, you may want to run “sudo apt- choose really don’t matter, as long as you get update && sudo apt-get upgrade” to keep them unique on your Local Area ensure that your OS is up to date. Fur- Network (LAN). sole thermore, we recommend you run the To change the MAC address of the i f “passwd” command and change the pass- onboard device, edit /etc/network/ X11 word for the odroid user to something a interfaces with your text editor of is not run- little more secure, or creating new user choice, and add the line “hwaddress ning.] accounts with the “adduser” command, ether newmac”, where newmac is an ad- such as by running “sudo adduser kilroy”. dress in the format “b6:8d:67:7b:cb:e0” In order to connect to your (Generally speaking, do three things key underneath the following labels: ODROID, you’ll need to discover the with your node passwords: make them hostname or IP address of the board. long, make them hard to guess, and store auto eth0 For the Ubuntu server image we used it in a secure location.) iface eth0 inet dhcp on our XU+E cluster, the default host- name is “odroid-server”, while for other Configuring Then, reboot the ODROID so the images we’ve used, it’s been “odroid”. Networking changes take effect. Make sure to verify Most home networks should support Before getting both ODROIDs on- the new address using the ifconfig com- DNS by default, which will allow you to line, we need to change a few settings as mand. Alternatively, you can opt to plug connect simply by the hostname. If this to eliminate hostname and MAC address your USB Ethernet adapters into the fails, you can alternatively connect using conflicts that may occur on your home USB 3.0 slot, and then run “ifconfig -a | the IP address assigned to the ODROID network with an ODROID cluster. To grep eth”, which should yield a list simi- by your router instead. If neither of the change the hostname, we will need to lar to this: hostnames resolves for you, check your edit two files, /etc/hostname and /etc/ router’s lease table to search for the IP hosts, changing “odroid-server’ to the eth0 Link encap:Ethernet address, often labeled as the DHCP cli- hostname of your choice and rebooting HWaddr b6:8d:67:7b:cb:e0 ent table in the router’s admin panel. the machine so the changes take effect. Since we used identical copies of the For the purposes of this article we will eth2 Link encap:Ethernet same image on both nodes, by default use odroid-server0 and odroid- server1 HWaddr 00:13:3b:99:92:b1 they had a hostname conflict, which we to refer to the first and second ODROID resolved by bringing them online one at respectively. Alternatively, if your operat- By default, eth0 will be the onboard a time, then changing the individual net- ing system supports it, you can also type 10/100 ethernet connection, while the work settings. If you don’t have access “sudo odroid-config” to change the host- second ethernet device (in this case,
ODROID MAGAZINE 9 HPC AT HOME
Use the appropriate ethernet device able through apt-get. id previously found with ifconfig (in To install MPICH, run “sudo apt-get this case, eth2). Then, power down the install mpich2”, or run “sudo apt-get in- ODROID, put the ethernet cable that stall openmpi-bin” to install OpenMPI was attached to the the onboard device as an alternative. into the USB ethernet adapter, and pow- er the ODROID back on. If, for some What you can do reason, you aren’t able to connect, try once you’ve loaded MPI: plugging the cable back into the on- board slot and verifying that the USB 1) Run test applications that ethernet adapter is still showing up us- use multiple cores on a single ing the “ifconfig -a” command. It’s also ODROID possible that the ethernet device ID itself has changed if the adapter is unseated, 2) Run example programs that in which case you can update the /etc/ use both ODROIDS and a total of network/interfaces file accordingly. 8 cores. At this point, the ODROID should be configured and accessible on the net- 3) Learn how to build your own work. Before heading on to the MPI MPI programs. section, configure the second ODROID using the same steps described above. In this article, we’ve focused on show- ing you how to do the first and the second Message Passing approaches. You can read the example Interface (MPI) programs that come with OpenMPI and Now that we have two nodes con- MPICH to learn more. There are also a figured appropriately, we can now number of excellent online tutorials and start looking towards how we can a few good books on programming MPI, execute HPC jobs on our two-node such as “Using MPI” from MIT Press cluster. A parallel programming en- (one of us co-authored that book). vironment such as MPI helps you do this. MPI takes care of starting Building it Better up the processes that make up the The content of this article represents parallel programming model, and just a fraction of what we will be able to provides a standardized applica- do with our cluster down the line. While tion programming interface (API) this setup is more than adequate for han- for those cooperating, communicating dling two nodes and only a few users, if Yes, we are serious when it comes to gi- sequential processes to use to make the we want to grow our cluster, we will want ant robots taking over your hometown, but Voltron always wins parallel program work. To accomplish to make use of a dedicated head node to this, we will make use of MPI, or Mes- better handle a larger number of users eth2) will be the USB Ethernet Adapter. sage Passing Interface, which provides and nodes. In addition to allowing us to If only eth0 shows up, try reseating your an API that allows nodes to send and re- hide cluster traffic from the rest of the USB Ethernet adapter and/or verifying ceive messages while processing jobs. A network, this head node will also host that it works on another machine. To command called either mpirun or mp- services that will streamline cluster man- set up the adapter for using DHCP on iexec will start all the processes needed agement, such as LDAP for user manage- boot to get an IP address, we will need to across your ODROIDS under your ment, Puppet for content management, modify /etc/network/interfaces control. There are two common open NFS for file sharing, and various net- and add the following two lines between source MPI implementations available working services. the entries for auto lo and auto eth0: for download - MPICH and OpenMPI. In part two of this series, we will For ODROID clustering purposes over begin to convert odroid-server0 into a auto eth2 Ethernet, both work equally well. Both proper head node. iface eth2 inet dhcp of these MPI implementations are avail-
ODROID MAGAZINE 10 POWER CONTROL ON ODROID CLUSTERS Fine-grained power control on ODROID clusters 24 high performance cores for 35 watts Kurt Keville
ur team has experimented re- cently with a number of new Oenergy-saving techniques avail- able to server system administrators and managers of High Performance Com- A big problem of early software engineering puting (HPC) clusters. Our specific ex- was not how much power those old dinosaurs periences come in the form of testing a demanded, but the lack of safety hats. mini-cluster of ARM Cortex-A9 boards running the development Ubuntu ver- sion targeted at that platform. The big takeaways standard practices of “nice” level man- agement and queueing system usage, In addition to the Hardkernel-rec- from this project ommended default install of the OS and most systems are fully in use if you orga- Server hibernate is of decreasing utility since concurrent headless server application nize your jobs correctly. We therefore in- poweroff and reboot is just as quick in our us- vestigated fully-on, fully-off and almost- suite (including MPI discussed on the age. Governer invocation is now the standard. last article), we installed cpufrequtils, off systems with an eye towards energy WattsUp, and PowerNap and then up- The Powersave governor is of considerable savings relative to the various options dated the systems accordingly. These value and should be used as a default in HPC available to us that don’t involve a full clusters. packages are mainly what we will discuss power-down. Cold boots time for our demo cluster in this article, since they are where the And manual processor affinity is no longer bulk of our power / energy savings and necessary if you are using modern kernels on was less than 10 seconds and therefore reporting are attained. your ODROIDs. validated this model. A more likely sce- The power savings are considerable nario for traditional datacenters, howev- in clusters that have significant reduced er, would include systems that are rarely usage periods, and an aggressive power- fitted U2 and U3s of less than 10 sec- powered down since they need to re- saving schedule yielded no negative re- onds so there is no argument you can spond to requests quicker than a power- sults in our findings. Even if you do not make for suspend / resume or hibernate on would allow. For those scenarios we have big.LITTLE enabled apps (which / thaw that isn’t better exemplified by an investigated suspend and resume and the we do not have on our U2 / U3 cluster), on / off solution or a scripted governor novel PowerNap acpi modes. you can tune your performance require- call in embedded HPC. Datacenter sysadmins have always ments with rules written against pack- In an academic datacenter, you are had a way to do a “safe” managed shut- ages like Slurm, which is currently one quite often utilizing 100% of your most down of their servers in case of a power of the most popular queueing systems / restrictive computational resources in outage. The UPS vendor APC, in partic- schedulers in the HPC world. your applications, or waiting for a job ular, has been a leader in this field when We have boot times on our eMMC to be initiated. Because of conventional they introduced their “SmartUPS” line.
ODROID MAGAZINE 11 POWER CONTROL ON ODROID CLUSTERS
The original software application that shipped with these UPSes utilized a seri- root@odroid:~# cpufreq-info al (RS-232) connection that would allow cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009 the system to initiate a shutdown script on a server when the UPS detected that Report errors and bugs to [email protected], please. it was no longer getting charged. Since analyzing CPU 0: driver: exynos_cpufreq the original releases there have been many improvements to this approach, CPUs which run at the same hardware frequency: 0 1 2 3 affording substantial scripting flexibility CPUs which need to have their frequency coordinated by software: to the sysadmin and introducing alter- 0 1 2 3 native hardware options, like USB and SNMP connections. maximum transition latency: 100.0 us. hardware limits: 200 MHz - 2.00 GHz The open-source community has also added many new options to this func- available cpufreq governors: conservative, userspace, tionality, progressively in the form of powersave,performance software support for the nut and upsd current policy: frequency should be within 200 MHz and 1.70 GHz. code bases (see http://www.networkup- The governor “performance” may decide which speed to use within stools.org). We can now “hook” the in- this range. vocation of this script into a user-defined current CPU frequency is 1.70 GHz (asserted by call to hard- usage, in our case tied to a drop in pro- ware). cessor usage below 20%. NUT is com- cpufreq stats: 2.00 GHz:0.00%, 1.92 GHz:0.00%, 1.80 GHz:0.00%, patible with Ganglia and Nagios in that 1.70 GHz:93.58%, 1.60 GHz:0.01%, 1.50 GHz:0.00%, 1.40 GHz:0.00%, it affords quite a few scripting options, 1.30 GHz:0.01%, 1.20 GHz:0.00%, 1.10 GHz:0.01%, 1000 MHz:0.00%, so sysadmins familiar with adding ad- 900 MHz:0.00%, 800 MHz:0.00%, 700 MHz:0.00%, 600 MHz:0.00%, 500 MHz:0.00%, 400 MHz:0.00%, 300 MHz:0.01%, 200 MHz:6.38% (66) hoc functionality to their cluster man- agement tools should have little problem integrating it with their custom setup. the course of the benchmark suite run. cpufreq-info will show this 4 times, but if you Additionally, cpufrequtils and pm- It is interesting to note that while these go for powersave or conservative, get ready to see less active processors when idle. utils are very handy sets of tools that are particular benchmarks managed to keep compatible with the Linux kernel, at the CPUs busy, it did not fully utilize least as recently as 3.2. PowerNap lets available memory, which is also reflected top command sampling a lu.A benchmark you manage this via a script interface. in power usage. You can lock your board into its highest top - 09:00:58 up 2:52, 6 users, load average: 2.41, 0.74, 0.29 speed setting by invoking “cpufreq- set –g performance” from the com- Tasks: 154 total, 2 running, 152 sleeping, 0 stopped, 0 zombie mand line or by hooking it into Power- %Cpu(s): 99.1 us, 0.0 sy, 0.0 ni, 0.8 id, 0.0 wa, 0.0 hi, 0.1 si, Nap’s config scripts if you prefer a degree 0.0 of automation. KiB Mem: 2071512 total, 884916 used, 1186596 free, 111884 buffers Note the ODROID U3 output KiB Swap: 0 total, 0 used, 0 free. 421392 cached above right, when your processors are set Mem to “performance” mode (one report for PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COM- each processor core normally). MAND When you set the U3 proces- sor frequency to the stock maximum 6306 root 20 0 69660 43248 644 R 394.9 2.1 3:59.17 lu.A of 1.7 Ghz and run the workload 6311 root 20 0 4708 1236 836 R 0.7 0.1 0:00.11 top at http://openbenchmarking. org/result/1401173-UT- Some benchmarks represent usage as connected WattsUp meter. Clearly the 1309189UT21, you can successfully 400% of one process rather than 100% XU-E is much better suited to this ex- peg the processors at close to maximum of 4 processes depending on whether periment, not to mention the substan- utilization. Our power peaked at 6.3 they are initiated as MPI jobs. We tially better performance with the big. Watts and averaged 5.6 per node over tracked the power use using an FTDI- LITTLE architecture.
ODROID MAGAZINE 12 POWER CONTROL ON ODROID CLUSTERS
Our test setup We wanted a demo micro-cluster Governor setting versus watt utilization that captured the power being used by six (6) ODROID-U2 computers. Governor (freq) Avg. Watts for 6 boards Those items were connected to our WattsUp meter, which allowed us to Performance (1.7 Ghz) 33.6 measure relatively small power fluc- tuations, since they aggregated. We Userspace (700 Mhz) 21.0 captured this with the Linux util- ity described below. Additionally, we Powersave w / 2 core* 3.6 measured single node numbers on an ODROID U3. Baseline power usage Performance w / 1 core 23.4 on boot (note that boots put us into * via a PowerNap script that invokes “echo 0 > /sys/devices/ ”ondemand” mode at initially 200 system/cpu/cpu2/online” and cpu3. Actually, if you set any fre- Mhz) was negligible. While a range quency below 700Mhz on the U3, it will turn off 2 cores. from 200 MHz to 1.7 GHz were Lower bars = less wattage usage available speed options for our boards (without overclocking), as a practical matter we only used the lowest and highest speeds. We measured the following scenari- os; All boards at peak freq, all boards at minimum freq while retaining all cores, all boards with 2 CPUs on at min, and all boards with 1 CPU on at max. PowerNap, in our conventional us- age, controlled cpufreqd to dial down the CPU speed to its factory-enabled minimum when an idle period is de- tected. An idle period can be user de- The SoC Drawer and SoX BoX clusters dis- fined, as well as other parameters as- assembled, those guys pack quite a punch sociated with reporting, grace periods and other functionalities. Our recommendations are to ig- nore hibernate in a server scenario; The power use logging setup if you need immediate shutdown using an ODROID-U3 just power off underutilized cores at a board level. Rebooting takes ~10 seconds each in our configurations. While the U3 might not compete with the XU on FLOPs per Watt, it does on References FLOPs per dollar. It is cheaper than an Intel Galileo and compares favorably PowerNap Tutorial http://ti- in the openbenchmarking tests by that nyurl.com/PowerNapTutorial standard. Moreover, it appears that power efficiency scales superlinearly Slurm Integration http:// with frequency and core count. So you tinyurl.com/SlurmIntegration if you have a power budget, and few Power Use Logging http://ti- time restrictions, you can script your nyurl.com/WattsUpLinuxUtil cpufreqd to make that a priority, and aggressive manage your power use.
ODROID MAGAZINE 13 USB GADGET DRIVERS
Gone are the days when notebooks came with Ethernet and COM ports. What do you do if you are stranded with nothing but a USB cable? usb gadget drivers make your odroid communicate with your oldschool PC Kevin Kim, Hardkernel Developer
Installation In order to use the Gadget drivers, first verify that the following modules are present on the ODROID system:
Mass storage emulation hen developing applica- By connecting the ODROID to a /lib/modules/`uname -r`/kernel/ tions for the ODROID, PC using its USB port, it can be "enu- drivers/usb/gadget/ W its often necessary to trans- merated" to appear as another common g_mass_storage.ko fer files and commands from a main USB device, depending on the type of host PC to the development comput- communication desired: Serial emulation er. This can be performed via FTP or /lib/modules/`uname -r`/kernel/ SSH through the Ethernet port, but it Serial communication device drivers/usb/gadget/g_serial.ko can be also be done over USB, to sim- plify the setup. This article describes Network device Ethernet emulation how to use the USB device port on /lib/modules/`uname -r`/kernel/drivers/ Mass storage device your ODROID to communicate with usb/gadget/g_ether.ko your host PC. To get started, a micro- USB cable is required to make a physi- You can also use the USB cable to em- Mass storage + Serial + Ethernet cal connection between ODROID and ulate each of these data connections at the /lib/modules/`uname -r`/kernel/drivers/ your host PC. same time, as a multi-function link. usb/gadget/g_multi.ko
ODROID MAGAZINE 14 USB GADGET DRIVERS
If the drivers aren’t initially present, Connect the ODROID’s micro-USB To emulate the Kernel and driver modules need to be cable to your PC and switch to using the a serial link : updated. Type the following commands Linux host. into a Terminal window to upgrade: Serial over USB On the Linux Host: $ mkdir update-kernel && cd Load the g_serial module on the update-kernel If a recent Linux distribution is in- ODROID: $ wget http://builder.mdrjr. stalled, the device should be automati- net/tools/kernel-update.sh cally mounted. Otherwise, follow these # sudo modprobe g_serial $ chmod +x kernel-update.sh steps to manually add it to the host PC: Launch dmesg and find the Serial $ sudo ./kernel-update.sh As root, launch dmesg and find Function gadget driver ready message. the /dev/sdX device assigned to the In the following code examples, the ODROID: # dmesg green characters show the Terminal win- … gadget: Gadget Serial v2.4 dow running on the ODROID, and the .. scsi 56:0:0:0: Direct- Access Linux File-CD Gadget … gadget: g_serial ready blue characters show the Terminal on 0308 PQ: 0 ANSI: 2 the Host PC. … g_serial gadget: high-speed .. sd 56:0:0:0: Attached scsi config #2: CDC ACM config Emulating a mass generic sg2 type 0 # ls –al /dev/ttyGS* storage device: .. sd 56:0:0:0: [sdc] 262144 512-byte logical blocks: (134 Storage over USB crw-rw---- 1 root dialout MB/128 MiB) 248, 0 Dec 31 1999 /dev/ ttyGS0 Load the g_mass_storage mod- .. sd 56:0:0:0: [sdc] Write ule with a storage node which will be Protect is off mounted on your host PC. .. sd 56:0:0:0: [sdc] Mode Connect the Micro-USB cable be- Sense: 00 00 00 00 tween the host PC and the ODROID, # mount which should give the following message .. sd 56:0:0:0: [sdc] Asking /dev/mmcblk0p1 on /media/boot for cache data failed on the host: type vfat (rw,nosuid,nodev,fl ush,umask=000) .. sd 56:0:0:0: [sdc] Assuming $ dmesg drive cache: write through # sudo umount /dev/mmcblk0p1 … usb 1-1.2.4: new high-speed .. sd 56:0:0:0: [sdc] Asking USB device number 3 using # sudo modprobe g_mass_stor- for cache data failed ehci_hcd age file=/dev/mmcblk0p1 .. sd 56:0:0:0: [sdc] Assuming … cdc_acm 1-1.2.4:2.0: This Launch dmesg and find the Mass_ drive cache: write through device cannot do calls on its Storage Function gadget driver message. own. It is not a modem. .. sdc: … cdc_acm 1-1.2.4:2.0: tty- … gadget: Mass Storage Func- .. sd 56:0:0:0: [sdc] Asking ACM0: USB ACM device tion, version: 2009/09/11 for cache data failed $ … gadget: Number of LUNs=1 .. sd 56:0:0:0: [sdc] Assuming … lun0: LUN: file: /dev/ drive cache: write through $ ls –al /dev/ttyACM* mmcblk0p1 .. sd 56:0:0:0: [sdc] At- crw-rw---- 1 root dialout … gadget: Mass Storage Gad- tached SCSI disk 166, 0 Jan 22 00:29 /dev/ get, version: 2009/09/11 ttyACM0 … gadget: userspace failed to Then, mount the device and enjoy provide iSerialNumber the file sharing: …gadget:g_mass_storage ready Data should now be transmitted $ sudo mount /dev/sdc /mnt/ … g_mass_storage tmp through /dev/ttyACM0 (PC), and gadget: high-speed config #1: /dev/ttyGS0 (ODROID): Linux File-Backed Storage $ cd /mnt/tmp
ODROID MAGAZINE 15 USB GADGET DRIVERS
errors:0 dropped:0 overruns:0 HWaddr 62:19:ce:95:e0:9f $ sudo chmod 666 /dev/ttyACM0 carrier:0 inet addr:192.168.100.1 $ echo qwerty > /dev/ttyACM0 collisions:0 Bcast:192.168.100.255 txqueuelen:1000 Mask:255.255.255.0 # cat /dev/ttyGS0 RX bytes:22645 (22.6 inet6 addr: qwerty KB) TX bytes:18987 (18.9 fe80::6019:ceff:fe95:e09f/64 KB) Scope:Link
Connect the Micro-USB cable be- UP BROADCAST RUN- Emulating a ethernet tween the host PC and the ODROID NING MULTICAST MTU:1500 Metric:1 storage link: and which should show the follow- ing messages on the host after typing RX packets:21 errors:0 Ethernet over USB “dmesg”: dropped:0 overruns:0 frame:0 Load the g_ether module on the TX packets:33 ODROID: $ dmesg errors:0 dropped:0 overruns:0 carrier:0 … usb 1-1.2.4: new high-speed # sudo modprobe g_ether USB device number 12 using collisions:0 ehci_hcd txqueuelen:1000
Launch dmesg to get the Ethernet … hub 1-1.2:1.0: unable to RX bytes:4677 (4.6 Function gadget driver ready message, and enumerate USB device on port KB) TX bytes:8394 (8.3 KB) details about the ethernet connection. 4 … usb 1-1.2.4: new high-speed # dmesg USB device number 13 using Now the ODROID will be able to ehci_hcd send and receive data through the usb0 … gadget: using random self ethernet address … cdc_eem 1-1.2.4:1.0: usb0: port: register 'cdc_eem' at usb- … gadget: using random host 0000:00:1a.0-1.2.4, CDC EEM ethernet address Device, 62:19:ce:95:e0:9f # sudo ifconfig usb0 192.168.100.2 … usb0: MAC $ ifconfig e2:53:36:a5:8f:38 # ifconfig usb0 Link encap:Ethernet … usb0: HOST MAC HWaddr 62:19:ce:95:e0:9f usb0 Link encap:Ethernet 76:42:28:9e:9f:eb HWaddr e2:53:36:a5:8f:38 inet6 addr: … gadget: Ethernet Gadget, fe80::6019:ceff:fe95:e09f/64 inet addr:192.168.100.2 version: Memorial Day 2008 Scope:Link Bcast:192.168.100.255 Mask:255.255.255.0 … gadget: g_ether ready UP BROADCAST RUN- NING MULTICAST MTU:1500 inet6 addr: … g_ether gadget: high-speed Metric:1 fe80::e053:36ff:fea5:8f38/64 config #1: CDC Ethernet (EEM) Scope:Link RX packets:3 errors:0 # ifconfig dropped:0 overruns:0 frame:0 UP BROADCAST RUN- NING MULTICAST MTU:1500 usb0 Link encap:Ethernet TX packets:4 Metric:1 HWaddr e2:53:36:a5:8f:38 errors:0 dropped:0 overruns:0 carrier:0 RX packets:594 inet6 addr: errors:0 dropped:0 overruns:0 fe80::e053:36ff:fea5:8f38/64 collisions:0 frame:0 Scope:Link txqueuelen:1000 TX packets:434 UP BROADCAST RUN- RX bytes:488 (488.0 errors:0 dropped:0 overruns:0 NING MULTICAST MTU:1500 B) TX bytes:624 (624.0 B) carrier:0 Metric:1 $ sudo ifconfig usb0 collisions:0 RX packets:106 192.168.100.1 txqueuelen:1000 errors:0 dropped:0 overruns:0 frame:0 $ ifconfig RX bytes:120002 (120.0 KB) TX bytes:98616 TX packets:82 usb0 Link encap:Ethernet (98.6 KB) ODROID MAGAZINE 16 USB GADGET DRIVERS
Being able to work alongside network, stor- age and serial, will save your life more often than you think.
192.168.100.2 port 34764 Emulating a multi # ping 192.168.100.1 [ ID] Interval Transfer function link: Bandwidth PING 192.168.100.1 The full package (192.168.100.1) 56(84) bytes of data. [ 4] 0.0-10.0 sec 193 MBytes 162 Mbits/sec A multi-function link emulates a 64 bytes from 192.168.100.1: mass storage, serial and ethernet con- icmp_seq=1 ttl=64 time=0.348 # iperf –c 192.168.100.1 nection using only one combo g_multi ms ------module: 64 bytes from 192.168.100.1: ------icmp_seq=2 ttl=64 time=0.254 ---- # mount ms Client connecting to /dev/mmcblk0p1 on /media/ ^C 192.168.100.1, TCP port 5001 boot type vfat (rw,nosuid,no dev,flush,umask=000) --- 192.168.100.1 ping sta- TCP window size: 20.7 KByte tistics --- (default) # sudo umount /dev/mmcblk0p1
2 packets transmitted, 2 re------# sudo modprobe g_multi file=/ ceived, 0% packet loss, time ------dev/mmcblk0p1 999ms ---- rtt min/avg/max/mdev = [ 3] local 192.168.100.2 After connecting the ODROID’s 0.254/0.301/0.348/0.047 ms port 34764 connected with 192.168.100.1 port 5001 Micro-USB cable to the PC, all three $ iperf –s functions listed above may be used si- [ ID] Interval Transfer multaneously. ------Bandwidth ------[ 3] 0.0-10.0 sec 193 MBytes 162 Mbits/sec Server listening on TCP port 5001 Wow! 162Mbps is faster than nor- TCP window size: 85.3 KByte mal 100Mbps Ethernet! (default)
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[ 4] local 192.168.100.1 port 5001 connected with ODROID MAGAZINE 17 GAMES Linux Gaming on ODROID The right system for your games Tobias Schaaf
hen it comes to gaming, ev- ing systems that the ODROID is able eryone has different tastes. to emulate, and compare their pro and W There are many gaming cons are to help you decide which is the genres, including First Person Shooter, best choice for you. This will somewhat Role Playing, Arcade, Adventure, Simu- reflect my own opinion, and might dif- lation, Real Time Strategy, and many fer from other people’s opinion, so more. Some games are better suited for please consider this article more as a consoles, while others are only playable suggestion than hard facts. if you have a mouse and keyboard avail- If you have already downloaded and able. Since the ODROID platform can installed my ODROID GameStation run many types of games, choosing your Turbo image, available for free on the gaming system really depends on per- ODROID forums, you have a good idea sonal preference. of what systems the ODROID is able to Nintendo Entertain- It also depends on whether you emulate. ment System or a Sega like to play on your own (single-player First on the list is the Amiga. I had Genesis, so I’m not able to mode), with others (team or competi- a few Amigas back in the day, and really compare the Amiga to other tion mode), on the internet (network loved to play games on it. In the 1990s, contemporary systems. mode), or with a friend in the same the Amiga was very popular. Compared In my opinion, the Amiga room in front of your TV (multi-player to other PCs of the day (Apple //GS, was far ahead of its time. With games or split screen mode). It also depends on Color Macintosh and IBM PC), it had whether you want the old classics with improved graphics and far better sounds The Amiga desktop. This was the system that the original beeping sounds, or prefer than most of the PC ports of that time. made all of your friends jelly, and you feeling high fidelity audio and video with or- I never had an actual console like a Super like the coolest kid in school. No kidding! chestral soundtracks and stunning 3D graphics. This month, I give an overview of the gaming opportunities that the ODROID platform offers, giving you some ideas regarding what games you might like to explore.
Finding the right system
Since the ODROID offers so many emulators and games, it’s hard to figure out what system to choose from. So, I want to examine some of the gam-
ODROID MAGAZINE 18 GAMES
The benefitpeople, including professional gamers. of the Amiga is The SNES was a big improvement com- that it actually pared to the NES and other consoles, but has some that is not a big surprise if you compare games the specs of the two consoles: that can The NES had only about 2KB of RAM and be played 2KB of Video RAM, and a maximum of 25 colors simultaneously (out of 48 colors together with and some grays). a friend, so I Its successor, the SNES, could use up to consider it a great 15bit colors (32,768 possible colors), and multiplayer system. had 128 KB of RAM and a large amount Games like Banshee or The Chaos En- of Video RAM (64 kB main RAM, 512 + 32 bytes sprite RAM, 256 × 15 bits palette gine Left: Banshee, a great Amiga shooter RAM). Right: The Chaos engine The ROM size of games from the NES were between 8 KB to 1MB On the SNES, the ROM size was be- that took 15 disks or more, are really awesome tween 256KB and 6MB. multi-tasking, the ability to to play with a use hard drives to store games friend. It was possible to pack and programs, and the Work- Next on much more data on a SNES bench Graphical User Interface, the list of emu- cartridge, which allows it was very impressive. lators is the Nin- for more content, and made There are some emulators tendo Entertain- games look a lot better, as seen that run Amiga games well, ment System (NES), in a direct comparison between but it takes lots of config- the Super Nintendo the NES and the SNES: uration to get the games Entertainment Sys- The SNES also used video render- to run, and often you have tem (SNES) and the GameBoy Advance ing layers, which allowed more effects to switch between Kickstart (GBA). If people talk about Nintendo, and content to put in a single scene, and disks (the BIOS of the Amiga). and especially about retro games, you are Simply switching through the going to hear about NES and SNES con- many disks can also get somewhat soles. The NES is rather old for a console, annoying. Although the graphics of the but it introduced some legendary classics Amiga was outstanding it can hardly com- that changed gaming history. Titles such pare to other consoles now. as Legend of Zelda or I use retroarch in my ODROID Super Mario are games GameStation Turbo image to run Ami- that will probably ga games, but unfortunately, not all of never be forgot- them run in full speed. So, I consider ten, and are one the Amiga an unstable system to actu- of the most ally use on the ODROID. There are important some emulators that can run directly of Nintendo’s (for example, E-UAE and FS-UAE), franchises. which give better performance than the The SNES was retroach port, but they require advanced a great improvement configuration, and won’t run easily with over the NES, since it gamepads, which the retroarch port does had more colors and well. There are some beautiful games on offered a lot more Zelda, Mario and Kirby, the the Amiga, but most of them have been possibilities than the best of Nintendo’s golden age ported to other consoles or to the PC, NES, and was, for a which can be emulated more success- very long time, THE fully. gaming console for
ODROID MAGAZINE 19 GAMES had a higher resolution than its prede- the lower resolution, the cartridge size cessor. went from 1MB up to 32MB. Another advantage of these consoles More size equals more content and was that they were made for two con- once again, the GBA was a big improve- trollers, which resulted in a large library ment when it came to content. It of- of games that could be played competi- fered movie cut-scenes, beautiful music, tively or cooperatively with friends. Be- and very nice graphics, which is why tween all of the consoles covered in this I prefer GBA emulation over SNES. article, I consider the SNES to be the Many games that existed on the SNES best console for multiplayer games. were ported to the GBA, and they not In my opinion, GBA is often over- only look much better, but in many looked when it comes to retro gaming cases, have additional content. GBA’s Riviera and Nintendo. The GBA was a handheld Although the GBA is, in my opinion, Promised console from Nintendo, very much like a far better console than the SNES, it Land the GameBoy (GB) and GameBoy Col- has a downside. The GBA is a handheld or (GBC), and was actually compatible console, and although it had multiplayer with both GB and GBC games. It even capabilities between two consoles via a had a second processor specifically for connection cable, it makes it impossible backwards compatibility, so that Game- to play GBA games with a friend on the Overall, I really like the Boy owners could still play their older same machine. GBA, and I routinely play games on the newer console. Otherwise, However, if you prefer single-player some GBA, since they have very it was very much like the SNES, which mode, you should definitely take a look attractive graphics and immersive game- made the small handheld device very at GBA games. You can also see if your play. All of the Nintendo systems (GB, powerful for its time. favorite SNES games exist for GBA, and GBC, GBA, NES, SNES) run fine on maybe get a newer, better experience the ODROID using the emulators pro- The GBA also had 15-bit color, and the CPU from your game. If you’re looking for vided on ODROID GameStation Tur- was 32-bit, as compared to the 16-bit pro- a new game to try, you should definitely bo. cessor of the SNES. It also offered 32KB + 96KB of Video RAM check out the GBA game library. I prefer to run SNES in retroarch and (internal to the CPU) and 256 KB WRAM play the other Nintendo emulators using (outside the CPU). mednafen since mednafen performs Final Fantasy IV better than retroarch for these plat- If you compare these specs, the GBA SNES vs GBA forms, and allows software scalers side by side. was a better system than the SNES in near- such as hq2x or super2xsai, which ly every aspect. The only advantage can enhance the picture quality that the SNES had over the GBA and make the games look more was the resolution, which was “modern” than they really are. only 240x160 pixels. Even with If you are a fan of retro Ar- cade machines, you’ll probably enjoy MAME, NeoGeo and Neo- Geo Pocket, which are available for the ODROID. MAME and Neo- Geo are available on retroarch, and NeoGeo Pocket is available on mednafen. NeoGeo Pocket is similar to the GBA, and is somewhere between a GBC and GBA, but it was not very popular, and lacks the large game library of its competitors. Still, it’s similar to the other Arcade ma- chines, and offers some challenging ac-
ODROID MAGAZINE 20 GAMES
as a PlayStation. Sega GameGear was also a Handheld The ODROID platform can run like the GBA or GBC. most of these games without issue, and Sega Systems always tried to be just a for this, it’s really nice to have. There little bit better than the Nintendo con- even is a project documented on the soles. The Sega Master System had more forum where someone built their own RAM and more colors than the NES, Arcade Machine at home with a U2: and was slightly faster. The most popular http://bit.ly/1cmrgjK. game was not actually Sonic the Hedge- Another big company back in the hog, but Alex Kidd in Miracle World. earlier days of console gaming was Sega, which directly competed with Ninten- GBA’s do. The Sega team had very good ideas, Summon Night but in the end, upset a lot of developers Swordcraft and publishers, and now Sega only pro- duces games for other consoles. The Sega MasterSystem, Sega Genesis tion games. (Mega Drive), and the Sega GameGear MAME and NeoGeo are the emulators that I included in the have a lot of fast action games ODROID GameSta- like Street Fighter 3 3rd Strike tion Turbo image, and 1944 The Loop Master. and are probably Arcade games vary from those their most well- that have simple graphics, to 3D known con- games, to some with sprite
Street Fighter 3 3rd Strike 1944 The Loop Master (NeoGeo) Sonic the Hedgehog Alex Kidd in Miracle World (Sega Master System) soles. They Double Dragon also produced a (NES) Double Dragon couple more sys- (SMS) tems like the Sega 32X, Sega Mega-CD, technology, like the previous mentioned Sega Saturn and 1944 The Loop Master. If you like a lot the Sega Dream- of action and expert gameplay, the Ar- cast, which cade games that the ODROID can run was actually is what you are looking for, especially a really nice when playing with friends. console, but it’s Still, Sonic was Sega’s answer However, the Arcade genre is limited, hard to find em- to Mario and it worked well for and implies fast action games. You will ulators to run these Sega. rarely find the RPG, Adventures or Sim- Systems on Linux ulation genres on an Arcade machine. and ARM so they are It’s hard to compare Arcade games with not included in the image (yet). If you compare the games available a SNES or Sega, since the Arcade games If you want to compare the differ- for the NES and Sega Master System evolved a lot, and so did the hardware ent Sega systems to others of its time, side-by-side, you can see that the Sega that was supporting these games. Some you could say the Sega Master System actually looked a lot better than the Arcade games have NES-quality graph- is comparable to the NES, the Sega NES. If your favorite game on the ics, while others have resolution as good Genesis is similar to the SNES, and the NES is also available for the Sega Mas-
ODROID MAGAZINE 21 GAMES
lustrators were involved in creating the available for the GameGear, and if it ran animations in the Sega Genesis version, on the Sega Master System, there is a which made them look much better. good chance that it was ported for the Sega tried to reach older gamers as GameGear as well. Even some of the well, and wanted to appeal to profes- sional gamers. For this, the uncensored version of Mortal Kombat was pub- lished on the Genesis, which had blood and other effects that had been removed from the SNES version. Gen- esis also pub- lished many
Genesis games were published for A comparison of the GameGear, so give it a try and SNES and Genesis graphics. see what you like best. Can you tell which system is which? The next console on the market to Earthworm Jim 2 make an impact on gaming was Sony ter System, I recommend Aladdin SNES vs. Aladdin Mortal Kombat sports games that with its PlayStation, although by now playing the Sega Master Sys- were very popular it’s considered retro as well. The Play- tem version instead. among adults. Station has an advantage over the pre- The next generation, called Overall, the SNES viously mentioned consoles, because the Sega Genesis, wasn’t as good had better hardware, it’s from a newer generation, but still as the SNES, since it had less and games looked it offers some console game classic that colors to choose from, and more impressive were updated for the new platform. developers had a hard time than the Sega Looking at the quality of the PS1 Genesis, but games, there are beautiful movies, Genesis tried to narrative speech, and high resolution counter that with graphics. The PS1 outranks all the pre- better game me- vious named consoles, and if you find chanics and more se- a game that was originally made for rious games and game- the SNES or Sega Genesis, you can ex- play. pect the PS1 version to have lots of ad- The Sega GameGear was meant to be ditional content like movie cut-scenes a superior handheld device and the di- and probably better music. rect competitor of the GameBoy (GB), Although the retroarch port of PS1 but it was far more than that. In fact, uses a software renderer to display its the Sega GameGear was even more pow- graphics, they perform fluently on the porting games to the Genesis since Nin- erful than the Sega Master System, and ODROID. Classics like Final Fantasy tendo did not allow its companies to had an adapter to watch TV. 7, 8 and 9 offer a few examples of its produce for any console other than Nin- The Sega GameGear is somewhere in high resolution graphics. Even better, tendo. Still, there were quite some nice between the Sega Master System and the the PS1 was designed for multiplayer, games for the Genesis, and they look Sega Genesis. It actually had even more which means you can play with some great. colors than the Genesis, but the down- friends on the same TV. Although you can see more details in side of the GameGear is that the reso- Finally, we reach the most impres- the SNES version of the game, the Sega lution was rather low even for its time, sive emulator on the ODROID so Genesis had better game mechanics and but that wasn’t important for a handheld far: PPSSPP, which can play Play- included a sword, which was not in the console. There were about 300 games Station Portable (PSP) games on the SNES version. Interestingly, Disney il-
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ODROID. The PSP runs a large collection of games that offer beautiful 3D graphics with movie cutscenes and real voice acting. Although PPSSPP runs best on a PC running Win- dows, Linux or Android, I also successfully ported it to the ODROID. There are lots of PSP- games that run quite nicely on the ODROID in an X11 envi- ronment using PPSSPP.
The Sony age, PS One’s Final Fantasy VIII, and the PSP games of Little Big planet, Soul Calibur, Fifa Soccer 2011, Wipeout Pure and Naruto Shippuden are all available for your ODROID
What emulator and what system is best for you? If we compare the different systems since its games look the best and lack the ability to play together with by their power, look and feel, consider- have an awesome look and feel, in someone else, unless you connect with ing color depth, game content, music my opinion. a friend over the Internet or through fidelity, and hardware technology, line Another way of deciding what your home network using two com- up nicely from least powerful to most games to try, might be whether the puters. powerful: emulators offers the opportunity to Each system that I covered in GB < GBC < NES < SMS < GameGear < Genesis < SNES < GBA < PS1 < PSP
Not included in this ranking is the to play with other people together this article has its own charm. Amiga, which is more like an old time in front of your TV. For multiplayer They all have some unique and en- PC, despite its variety of games and gaming, the best consoles are MAME, gaging games, and it’s usually the other options. Amiga games ranged NeoGeo, SNES and the PS1. There gameplay, not the graphics, that from very simple to spectacular, offers are also multiplayer games for Sega makes a particular game so enjoy- beautiful music and even more colors Master System and Sega Genesis as able. With an ODROID, you have than an SNES or GBA - up to 24bit. well, but I encountered them rather the possibility of experiencing all Also missing are the Arcade ma- rarely, so I think that SNES would of them just by switching from one chines: NeoGeo Pocket, NeoGeo be the best choice if you want to play emulator to another. And, with and MAME, since these systems of- with a friend. ODROID GameStation Turbo, you fer a variety of games from the classic Although handheld devices such have all of these emulators already Pac-Man up to Tekken 6 for the PS1. as the GBA might be the best single- set up, ready to play games with Of these consoles, I prefer NeoGeo, player gaming console, they normally your favorite controller.
ODROID MAGAZINE 23 TECHNICAL ARTICLE Estimating Radio Network Interference With Multi-threaded Java Jussi Opas
he project described in this ar- It is of interest to see that adding even ticle involves the estimation of more equally performing cores short- T radio network interference using ens the used time, but not by much, as a multi-threaded Java application. How shown by the dashed line. The sequen- does the ODROID compare to other tially done 2-unit work throttles the computers performing the same work? overall performance. If the full benefit If some tasks can be parallelized, of all cores is the goal, then also the pre- then each additional thread shortens viously sequential work should be paral- the execution time of the whole job. lelized. The compilation time of Linux Compilation time of Linux kernel on XU, the Given that there is an execution process kernel on ODROID XU demonstrates time unit in minutes. available for performing each added this expectation model well at right. thread, let’s say that it takes 8 units Our sample application, called Poiju, to do some work sequentially. Add- computes estimation of radio network The characteristics of the program ing one new thread shortens the time interference at the beginning of next are that it uses only RAM (no file ac- to 4 units, while adding a third thread page. To do the estimation, combined cess), and all work can be done by the further shortens to 2.67 units, and the coverage and service area of each radio CPU, since no GPU-related work is 4th additional thread lessens the time cell must be calculated. Then, at each performed. Parallelization has been to 2 units. If the work is not fully par- pixel, the field strength of interfering designed so that, for each cell, service allelizable, there is always some portion cells is computed. This is done over the area is computed first sequentially, that must be done in sequence by one service area of carrier cells. Computation and after that interference is comput- thread, and that part of the work can- is made on pixels of size from 30 to 350 ed with many threads for cell specific not be accelerated by adding threads. meters. The size of radio cells may vary closest candidates. Let’s start with the assumption from 200 meter to 50 kilometers. Physical cores and/or hyper threads that the non-parallelizable work takes The computational challenge is expo- are visible as available processors 2 units to perform, and assume that nential in its nature, as the amount of pixels [LEA99]. Java threads hide underly- adding more threads does not incur to visit and to compute grows in potency ing operating system and hardware, so any extra cost. Then, we add up to 12 when a more accurate resolution is used. the same program can be used on all threads. The whole work should then platforms whereever a virtual be done in constant time from the 4th machine is available. To imple- to the 12th thread. With this informa- ment threads, we used Java’s tion, we can draft an expectation mod- modern concurrency package. el, as shown by the square dotted solid A typical development ses- line to the right. sion with the application Poiju is shown on the next page. The Expectation model; theoretical performance prediction parameters dialog curves for multi core processors. is shown in the front, and the main window of the Poiju ap-
ODROID MAGAZINE 24 TECHNICAL ARTICLE
final long t1 = System. The performance nanoTime(); of the application final double distance = on XU is practically SpatialMath.computeProjectedDi identical between 4 stance(carrier, candidate); different Linux dis- instrument. tributions, Debian, incrementDistanceTime(System. Xubuntu, Fedora and nanoTime() - t1); Ubuntu with Mate desktop. There is a measurement results small, but hardly vis- with OpenJDK and ible, improvement in JDK releases 1.6, OracleJDK are shown 1.7, and 1.8. It is also of interest to see below right. how performance is improved when fre- The first observa- quency is changed from 1.6 to 1.8 GHz, tion is that our theo- as shown in at end of this page. retical model, as pre- sented before, is being Running times on 4 A15 core XU board with plication is below it. Also shown are the partially followed. two different JDKs. htop terminal and the lowest application is Each added thread is speed- the development environment called Iltel- ing up the program execution, liJ IDEA. until the 4th thread. The first The ODROID-XU’s ARM proces- added thread yields the best sor offers 4 power efficient A7 cores performance boost. This is and 4 high performance A15 cores partially affected also by Just In [ARM13]. At any one time, either a Time (JIT) compilation. JIT cluster of little cores or a cluster of big improves execution perfor- cores is working, known as big.LIT- mance when same byte code is TLE architecture. Hence, there are 4 executed repeatedly. processes available. The Poiju applica- Adding the 3rd and the 4th threads With htop and vmstat we see that tion is using only the big cores while predictably improves performance, more than half of the time is used by ker- intensive computations are made. while the addition of the 5th thread de- nel instead of user space. This is a major The performance of application is creases performance. We guess here that problem that we so far noticed only on measured with self made instrumenta- thread scheduling and context switch- XU. What is wrong in the application? tion by taking core-specific times prior ing does not come for free, when there If there is some internal error in a pro- to doing something, and then the next are many threads waiting for execution gram and a lot of exception are thrown time right after doing the task: time. When we know this, it is better to and treated silently, it would affect the We are doing all tests with 10,000 ra- limit the number of threads to 4 in the performance significantly. However, dio cells at each time. The performance application program. That can be done that should not be visible as kernel time. by calling the Runtime.getRuntime(). After several other similar guesses and availableProcessors() method. We see Poiju in development session on ODROID XU on a monitor via display port. also that OracleJDK is performing bet- Over-clocking improves performance, but ter than OpenJDK. Open- dropping usage of self-made instrumenta- tion improves it significantly. JDK is the default installed Java on Ubuntu, so the user must manually in- stall Oracle JDK. Fortunately, it is freely available from the Oracle Develop- er website.
ODROID MAGAZINE 25 TECHNICAL ARTICLE
when 5 and more threads are the 4th thread and put the numbers of used. From the vmstat output partially and fully parallel runs into one we can produce a graph, where illustration below. user space time and idle time In this test, the multi-core ARM is shown together with perfor- processor is doing its jobs much faster mance, see the figure at bot- than the one core Celeron processor. tom left. With 4 threads, the performance is We don’t know the actual 1.8x better. Meanwhile, the mobile reason for the behavior, but i5 processor is 3.3x faster than the trials we were not able to find the rea- we can guess things like con- XU. Fully parallel thread configura- son. Finally, we commented self-made text switching is not efficient, detailed instrumentation that was being or work load is not even but generated with Java’s nanoTime method. unbalanced, or the share of As a result, two-thirds of the computa- sequential work is large, or tion time disappeared. something similar. The first We can expect that nanoTime inef- guess can be sorted out with ficiency and any other similar feature the following reasoning: 1) of Java on ARM will be streamlined in there are no problems in future, as there is news of co-operation multi-threaded Linux ker- [JAC13]. Since we let the ARM proces- nel compilation, 2) literature sor do the work that traditionally has search shows that context Performance profile when the application is been assigned to desktop computers, we switch time should be at maximum fully parallelized. also made a comparison with two lap- 0.4 % of overall time [DAV07], and top computers, one having a Celeron 3) the development environment - Comparison of i5, XU and Celeron when 4 processor at 2GHz and another having IntelliJ IDEA - uses multiple threads threads are used. an i5-2520M at 2.5GHz. The Celeron flawlessly. We leave the cause has one core while the i5m has 2 cores as a puzzle to be solved. with 2 hyper threads. We refer to these For an alternative ap- processors as x64 to signify that they are proach, we implemented 64 bit x86 processors. The comparison is threading differently, and shown above. also made a couple of other With this different scale in the graph, changes. Now, cells are or- it is obvious that something starts to ganized into as many work throttle the performance from the 5th lists as there are threads to thread on. Adding more threads, up to be used. Both service areas 12, does not seem to degrade the per- and interferences are com- formance of the one core Celeron at all. puted in parallel, so there are N cells tion changes these numbers to 2.5x Meanwhile, we see that the application being computed at same time. The and 3.2x respectively. In this compar- performance at XU is being degraded work is now fully, or almost fully, ison, the XU does 1/3rd of the work parallelized, and the performance of that an I5 can do at the same time. Processor is not loaded, instead there is the application clearly improved. The free capacity. Performance graph follows now our Summary expectation model. Multi- The ODROID XU board performs the threading uses the whole same Java tasks for which desktop comput- capacity of the XU board. ers have been traditionally used. Although In this comparison, the it can’t compete against the brand new ODROID-XU was used at (and more expensive) x64 processors, it 1.6 GHz with the perfor- can be used as a replacement for a mobile mance governor option. i5. The ODROID-XU is clearly better To make a more legible than an older single-core x64 computer, comparison, we take times at and Java applications benefit significantly
ODROID MAGAZINE 26 TECHNICAL ARTICLE
from the usage of multiple threads. Through this exercise, the per- bana, IL. 5 pp. 2007. http:// formance of the Poiju on other plat- www.cs.huji.ac.il/~feit/exp/ The default on-demand governor of Linux is forms was improved by 40%. On the expcs07/papers/136.pdf biasing performance test results, because ODROID-XU alone, the improvement the CPU’s clock frequency is being changed automatically. Therefore, in Linux, one should was huge from the initial design stage. [LEA99] Lea Doug. Concur- use performance frequency scaling governor In general, desktop Java applications can rent Programming in Java, De- during performance tests. be improved when they are also tested sign Principles and Patterns, on the ARM-based XU. The ODROID Second Edition. Addison Wes- The System.nanoTime method costs a lot of computes interference estimate to 10, ley. ISBN 0-201-31009-0. 411 kernel time. The nanoTime method problem affects both Celeron and ARM processors, 000 radio cells in 9.6 seconds by using pages. November 1999. while the mobile i5 processor does not suffer pixel based computation and multi- from it as much. The call to nanoTime should threaded Java. [ARM13] ARM Limited. Multi- be commented out in production code. This exercise has been made as an ad- threading technology and the hoc, BYOD type project. The content challenges of meeting perfor- When high work load is given to parallel threads, then an equal amount of threads to here as such does not imply anything mance and power consumption the number of available processors should be about actual products of NSN. demands for mobile applica- used. The Runtime.getRuntime(). tions. 9 pages, 2013. availableProcessors() method can References be can be used for this purpose. [DAV07] David F. M., Car- [JAC13] Jackson Joab. Ora- Use Linux tools like vmstat and htop to vali- lyle J. C., and Campbell R. cle and ARM to tweak Java. 2 date loading and kernel time. For profiling H. Context Switch Overheads on pages. 2013. http://www.java- an application, jvisualvm in JDK’s bin di- Mobile Device Platforms. Uni- world.com/article/2078833/en- rectory can be used. Don’t trust self-made versity of Illinois at Urbana- terprise-java/oracle-and-arm- instrumentation without a backup mea- Champaign 201 N Goodwin Ave Ur- to-tweak-java.html surement tool.
7/24/13 vi-vim-cheat-sheet.gif (1024×724) Dear reader: I honestly have to make a better cheat sheet than this one, but this one has helped me has helped this one but this one, sheet than cheat better make a to have honestly I reader: Dear immensly for the article me, it will help you on the next page. on countless occasions, and believe Bruno Doiche Sincerely
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www.viemu.com/vi-vim-cheat-sheet.gif 1/1 HOW TO INSTALL REBOL how to install rebol A Beginner’s Guide by Bohdan Lechnowsky, Editor
ebol (Relative Expression the name under which you Based Object Language)is a want your script to be saved Rrevolutionary advancement in (see “vi cheat sheet” above programming language emerging from for some basics on how to over thirty years of language research. use it). It offers enormous flexibility and pow- After editing your script, er, with a focus on intuitive language you will need to change the permissions p Paste yanked data patterns that promote new ways of so it can be accessed by Rebol 3 (exam- : Enter extended command mode. thinking about software tasks. ple: chmod 755 myscript.r) Here are a few extended commands: w Write (save) the file Follow these steps to install open- vi Cheat Sheet q Quit (don’t save) the file source Rebol 3 with GUI support: “vi” was created back in the days wq Write and quit when there were very few special keys q! Quit, even if the file has Open a web browser and navigate to on computer keyboards. Keys like been changed since last write http://development. saphirion.com/experimen- “Esc” (escape) and the arrow cursor / Search forward for the text tal/builds/android/ keys didn’t even exist. One of the great following the slash Download r3-droid.apk (amazingly, advantages of the vi editor is that it is ? Search backward for the text it’s smaller than 2MB). available on nearly any unix-based op- following the slash When finished, double-click on the down- erating system, including Android. load icon (usually by the clock) and grant in- stallation permissions. Because of the early limitations of There are much more in-depth vi Go to the apps list, and click the icon for computer keyboards, vi was designed to cheat sheets online, but the above com- R3/Droid. have two modes. The first is the input mands should allow you to edit just mode, and the other is the command about anything you need in vi. Al- Additional mode. On the Android version of vi, though it may seem uncomfortable to Android notes: these two modes are toggled by pressing use at first, seasoned vi users can often When using the Android Ter- CTRL and [ (more simply referred to edit more efficiently than users on any minal app, it is almost always neces- as CTRL+[). During input mode, any other editor, graphical or not. sary to have root permissions. To login key you type is entered at its face value. as root, enter “su” at the command During command mode, here are some prompt. This needs to be performed helpful commands: On Ubuntu/ARM each time Terminal is opened. As open-source Rebol 3 is still in very On my installation of Android, I i Insert at current position active development, the graphical port commonly get a message when I try to I Insert at beginning of line of Rebol for ARM has not yet been re- create a new file, stating “Read-only a Append at current position leased. According to the developers at file system”. To overcome this, enter A Append at end of line Saphirion, they predict a working ARM “mount -o remount /” at the command dd Delete current line port of Rebol 3 with graphics to be avail- prompt. This needs to be performed yy Yank (copy) current line able sometime in February or March each time Terminal is opened. . Repeat last command 2014. Keep checking the http:// To edit a script using Terminal, en- cw Change current word development.saphirion.com/ex- ter vi myscript.r where “myscript.r” is dw Delete current word perimental/builds directory for an
ODROID MAGAZINE 28 PROGRAMMING WITH REBOL
ARM port. The graphical version for Linux x86 is already available, but it Programming won’t work on your ODROID. The Linux ports are being helped heavily by a partnership with Saphirion and other with rebol commercial interests, so expect a lot of movement in this area over the next few Reducing Complexity in Development months. In the meantime, Rebol 3 is avail- by Nick Antonaccio and Bohdan Lechnowsky, Editor able in the non-GUI variety from http://rebolsource.net, and crophones, speakers, GPS and other sen- can work wonders as a replacement to Why Rebol? sors are built into every tablet, phone, bash, perl, PHP, Python and other lan- Modern software development tools netbook, and desktop PC, and they guages that don’t have a native GUI. are overly complex. Creating even a work transparently without having to small program to allow users to com- install hardware, drivers, or OS patches. plete the most basic computing task Tiny form factors, like ODROID, Follow these steps to install Rebol typically requires the installation of a and inexpensive cellular network con- 3 on Ubuntu/ARM: complex Integrated Desktop Environ- nections, enable new types of applica- ment (IDE), a bloated Software Devel- tions that weren’t practical, even on Open a browser and navigate to http://re- opment Kit (SDK), and other support- laptop machines, a few years ago. The bolsource.net. Locate the download for Linux ARM. It comes ing tools. Developers need a working high-speed quad-core ODROID pro- in two variants: hard float and soft float. Either knowledge of diverse chains of tools cessors, not to mention even the least should work fine, but if you have trouble, the soft patched together, along with library expensive modern phones and tablets, float version is likely more compatible with most Application Programming Interfaces run circles around the best desktop PCs systems. After downloading, open Terminal and rename the (API), database systems, and more just of a decade ago. Deep data content of downloaded file to “r3” for ease-of-use (example: to create a simple application. every sort, in every field of study and sudo mv r3-linux-arm-g4d9840f r3) For most developers, the thought interest, is available instantly online to Also, change permissions to allow executing the of building mobile apps, desktop GUI anyone around the globe. Mainstream file (example: sudo chmod 755 ./r3) programs, and web applications repre- handheld hardware is tiny, the interfaces To run it, enter sudo . To execute a ./r3 sents mastering a tremendous variety are beautiful, standard formats exist for script located in a file, enter sudo ./r3 myscript.r. You can even execute scripts of in-congruent work flow patterns, virtually every type of data (images, au- located on the Internet like this: sudo ./r3 incompatible data formats, and incon- dio, video, structured tables of text and http://mysite.com/myscript.r. sistent development methodologies that numeric data, etc.), and well known op- sap productivity at every turn. For these erating systems and software all function developers, it’s an unavoidable part of in a relatively uniform and familiar way, If opening Rebol 3 without launch- the job. so that everything just “works” the way ing a script, you can now type any Rebol We live in a time when ubiquitous that users expect. commands at the command prompt. and inexpensive handheld wireless de- Being able to use the amazing pro- vices and ODROIDs connect us all to grammable network-connected comput- an enormous world of useful data re- ing power in our pockets, and all around sources. Those devices enable critical us, makes available enormous cultural data management, communications, potential that has never before been business transactions, entertainment, available, and gives us the ability to cre- and other practical benefits which deep- ate custom applications which leverage ly affect the nature and quality of our that tremendous power will only con- daily lives. tinue to grow in importance for future The primary frustrations of device generations. ownership have been eliminated by new This situation is fantastic for users of generations of technology. Users don’t “apps”, but for software developers, the need to know how networks work to current landscape of tools is a painful connect to the Internet. Cameras, mi- mess. The remnants of every legacy soft-
ODROID MAGAZINE 29 PROGRAMMING WITH REBOL ware and hardware solution still haunts gone, includingmore than 40 hardware and it’s shockingly simple to learn and and infects the process of writing mod- platforms and operating systems so far, use. An entire development toolkit for ernized code. Numerous attempts to and the web. R3 requires less than a minute to install, standardize on different commercially- All the core components that make since absolutely no hefty SDK or IDE motivated platforms and formats have modern computing possible - graphic installations are required, even for An- led to the need to support a huge vari- user interfaces, network connectivity, droid development. ety of data structures, language syntaxes, manipulation of standard data formats, Rebol works the exact same way on and tool sets. etc. are handled in Rebol using the sim- every platform, without any changes To even begin creating a typical “hello plest possible syntax, and implemented to code or workflow routine. Even world” app for Android, you need to install using a tiny interpreter that runs exactly people who spend the majority of their hundreds of megabytes of software onto a the same way on every operating system. time doing things other than writ- desktop computer, including an Integrated Rebol was designed from the ground ing code can learn to create powerful Development Environment (IDE), a Soft- up to eliminate complexity caused by custom business and personal applica- ware Development Kit (SDK), a device patching together disparate tools, and it tions with it, quickly and easily, on any emulator, and any “productivity enhanc- succeeds brilliantly in that regard. chosen platform. ing” tools that help ease the wildly com- Rebol side-steps most of the mess Despite its extremely simple na- plex process of writing an applications. that has evolved over the years in main- ture, R3 is not a hobbyist toy or lim- Even for seasoned developers, modern stream software development technolo- ited learning environment. Rebol is application development is a weighty en- gy, and for a wide range of common de- a powerful and deep professional tool deavor. If you also intend to port your ap- velopment tasks, it “just works” quickly, which has proven itself in numerous plications across mobile, desktop and web easily, and more simply than can be critical commercial projects, across platforms, you need truly deep experience, imagined by anyone mired in the mess a wide array of demanding industry skill, and lots of time. of traditional programming tools. environments, around the world, for It’s not uncommon to see teams of pro- Rebol has a special ability to wrap more than a decade. fessional engineers devote themselves to new capabilities into simple language building and supporting a single applica- structures (also known as “dialects”, Examples of Rebol’s practical tion. Despite the fact that Android is an domain specific languages, or “DSL”s) application in the real world open platform, today’s devices feel closed, which control multiple layers of com- Quick schedule apps or at least cumbersome, for developers. puting functionality. It goes far beyond The hurdles to learning how to program the abilities promised by old, rigid Ob- Email programs with special features for are too much for all but full time develop- ject Oriented Programming (OOP) ap- personal use ers. Gone are the days when even hobby- proaches, and it has a proven record of ists could write useful custom applications reducing complexity in widely varied Business applications to handle inventory, sales and employee management for their personal and business computing development tasks. devices. Recently, Rebol version 3 (“Rebol 3” Niche commercial applications intended for There was a time in our history when or “R3”) was released by Carl Sassenrath international re-sale this activity was just as popular, accessible as an open source project, and a version and even fun for users as running commer- for Android named “Saphir” is forked Distributed apps to organize group activi- ties for your local school cial apps. It’s a shame, because never before and maintained by the Saphirion group. has there been such a tremendous variety Saphirion is a commercial application Web apps to manage membership routines of knowledge and useful computing capa- development company that uses Rebol for an online club bility sitting at our fingertips. as their primary development tool. Free, open source R3 Saphir releases also exist Hardware interfaces to control computer- ized machinery in your home or business Rebol for Windows, Mac, and Linux desktop On All Platforms operating systems, and R3 server ver- Systems to manage robotics at brand name For more than a decade, a small sions enable easy and portable web de- manufacturing facilities group of developers, coding in Rebol, velopment strategies. have known what it means to be truly In most cases, Saphir R3 download productive, using a single simple tool to sizes range between 0.5 and 1.5 mega- Evolution of Rebol create applications of all types, for ev- bytes, with GUI, networking, and all For most of its life, Rebol 2 was a ery popular platform that has come and other required components included, closed source commercial tool which
ODROID MAGAZINE 30 PROGRAMMING WITH REBOL
thrived as a “secret weapon” among only bit.ly/1tHdcbS for their “Natural maps directly to something that appears a small community of users who com- scope of application”. Notice how Red, on screen. There is no wasted syntax - municated privately and covertly using coupled with Red/System, cover the entire you really don’t even need to understand invite-only communication channels, stack of application abstraction levels, even anything about “programming” to fol- the executables of which were developed more so than Rebol itself. low what this code does: using Rebol 2. With the release of open source R3 Another language load-gui and the new potential for Android de- to learn? view [ velopment, in addition to more than I’ve heard it all 40 legacy platforms and web develop- before! field ment, Rebol has attracted a new group area of coders interested in its practical and Before starting on this section, make productive capabilities for creating sure you have completed the Rebol 3 check software of all sorts. In future articles, installation outlined in the article by radio we will show you how easy it is to get Bohdan Lechnowsky in this same issue. started. The screenshots shown in this and future text-list articles are taken from a Windows work- text-table Red station, but will look nearly identical on On All Platforms Ubuntu, Android, or any of the other drop-down During the closed-source era of Re- operating systems supported by Rebol 3. button bol 2 and 3, several languages were de- For years, developers have been hear- veloped as open-source variants of Rebol ing that some “new” language technol- ] including Boron, Topaz, World and Red. ogy will supposedly cut their develop- On Android, the Rebol command The data-interchange format, JavaScript ment time by orders of magnitude. That line currently only takes single-line com- Object Notation (JSON), was also heav- sort of talk is so common that it falls on mands. This is not a problem, as Rebol ily inspired by Rebol’s clean data format. deaf ears. This introductory section pro- is syntax-free. Simply enter the com- The front-runner of these efforts vides a few short examples to substanti- mand like this on Android: presently is Red, which also has a low- ate some of the productive capabilities load-gui level subsystem called Red/System. which Rebolers enjoy. Nothing else even While Rebol is an interpreted-only lan- comes close to its simplicity. view [field area check radio guage, Red and Red/System can run ei- Using R3, you can build a GUI “hello text-list text-table drop- down button] ther as an interpreted language or as a world” application for Android, Linux, compiled language. Red’s founder and Windows, and Mac as simply as this: Alternatively, multi-line programs lead developer is Nenad Rakocevic, aka can be written with any text editor, and “DocKimbel”. load-gui executed using Rebol. For instance, if The Rebol language family was recently view [text “Hello World!”] you create a file called gui-demo.r that recognized as the most expressive multi- you can execute from the Rebol 3 com- purpose languages, as seen in the chart at On Android, there will be no “close” mand line: http://bit.ly/1iikG1r. Expressive- button on the window, so press “Escape” do %gui-demo.r ness is the measure of what can be accom- on the keyboard to get back to the Rebol plished by a given amount of coding. command line. That’s it! The only two languages rated as The program above is much more Pleas note that Rebol has numerous more expressive than Rebol are Augeas than the typical text-based console “hel- GUI dialects. The examples shown in and Puppet, both of which are not gen- lo world” app. It’s actually a complete this and future articles make use of the eral-purpose. Red falls in the same cat- windowed form, capable of displaying “R3-GUI” dialect, which is based on, egory as Rebol as far as expressiveness is all sorts of other useful Graphic User In- and very similar to, the popular Rebol 2 concerned. terface (GUI) widgets. Visual Interface Dialect (VID). Red, along with Red/System, is the first Here’s another simple program that In the next article, we’ll look at creat- real contender to be a “full-stack” program- displays some text entry fields, buttons, ing a fully functional text editor, graphi- ming solution. Several popular languages lists, and other common GUI widgets. cal calculator, and more! are compared and contrasted at http:// Notice that every single widget word
ODROID MAGAZINE 31 IO PORTS ON ODROID-U3 I/O Shield Access using the C/C++ language for ODROID-U3 Justin Lee and Kevin Kim
ne of the exciting accessories Usage available for the ODROID-U3 Ois the I/O shield, which was Download the Firmata designed as versatile, general-purpose software for I/O shield, and set- Making a Test data acquisition and control module up the configuration as follows: Circuit with the U3 to provide a direct connection to the I/O shield and the Port setup : ODROID-U3 I/O connector. Tinkering Kit The I/O shield includes a big pro- Tools > Serial Port > /dev/tty- ACM99 totyping area, so you can wire up DIP Use the following parts from the tin- chips, sensors, and more. Along the kering kit, also available from the Hard- edges, all the GPIO/ADC/PWM and Open the example code and upload kernel website: B, C, E, G, H, I, J: power connectors are broken out to 0.1” it to your IO_shield: pins for ease of access. There are also File > Examples > Firmata > Stan- two 3-pin headers for small servo motor dardFirmata connections, and a 10-pin connector of I2C/GPIO for further expansion. Download the I/O shield source code This article will get you started with http://dn.odroid.com/U3_ using the I/O shield using examples in Accessory/u3_IOshield_ex- the C++ language. ample.tgz
1. Extract source code using the “tar -xvzf” Installation command.
The drivers are installed by default 2. Build the libfirmatac.a library. on Ubuntu 13.10, which is available for download from the ODROID forums. 3. Build the Example code which links Verify that you have the following mod- libfirmatac.a: ule (Ti’s TCA6416A I2C to Parallel Port Ex- pander) in your kernel source tree: /lib/ ledBlink.ex is an IO Shield ‘D13’ modules/`uname -r`/ kernel/ port LED blink example. drivers/gpio/gpio-pca953x.ko servotest.ex is an IO Shield ‘D3’ port servo motor control example.
Firmata example code
Launch Ubuntu Software Center, search for “arduino”, and install it
ODROID MAGAZINE 32 IO PORTS ON ODROID-U3
sys/class/gpio. limitation by using a conf file to launch the If you want to work with a particular module as a daemon, then using a shell GPIO, you must first reserve it, set the script to perform the initialization: input/output direction, then start man- aging it. Once you reserve the GPIO 1) Create the file/etc/init/ and finish using it, you also need to free tca6416.conf, which may require it, to allow other modules or processes to root privileges: use them. This rule applies whether you want to use the GPIO from the kernel or description “TCA6416 Module Initialization” at the user level. start on runlevel [2345] GPIO Export exec /usr/sbin/tca6416init. By typing “sudo modprobe” in the sh Terminal window after booting the Linux kernel, the GPIO driver and TCA6426 devices will be attached to the i2c-gpio.4 2) Create the file/usr/sbin/ Match the simple circuit shown here, and have your U3 as shown below bus. 16 Ports are mapped to GPIO tca6416init.sh: #289~#304 (I/O Shield pin num- ber P00~P07, P10~P17): #!/bin/bash # Load the Kernel Module # sudo modprobe gpio- pca953x modprobe gpio-pca953x
# sudo su –c ‘echo tca6416 # Set the I2C address of the 0x20 > /sys/devices/plat- module form/i2c-gpio.4/i2c-4/new_ device echo tca6416 0x20 > /sys/de- vices/platform/i2c-gpio.4/ # dmesg i2c-4/new_device
Accessing the … i2c i2c-4: new_device: In- # Enable all GPIO’s on the stantiated device tca6416 at board GPIO from the Linux 0x20 User Space for gpio_n in `seq 289 304`
GPIO means “General Purpose Input/ Next, build the u3_shield_GPIO_ do Output”, and is a special pin present in sysfs.c, located in the examples folder, some chips that can be set as either input using g++. Please note that the GPIO- echo $gpio_n > /sys/class/ gpio/export or output, and is used to move a signal high sys_init() function need the super-user or low (in output mode) or to get the sig- permission to do modprobe and attach done nal current status (in input mode). Usually, i2c device. The default password on the these pin are directly managed by kernel official Hardkernel images is “odroid”. By adding these two files, all the modules, but there is an easy way to man- P00 port : LED blink GPIO ports will be permanently en- age these pins from the user space as well. P10 port : key press, then GPIO abled on reboot. You can also add your Standard Linux kernels contain a special 297 read value = 0, otherwise GPIO application software in the “tca6416init. interface which allows access to the GPIO 297 read value = 1 sh” as an alternative method. pins. By running the kernel menuconfig command before compiling the kernel, you Starting your can easily verify if this interface is active, and application software Additional Credits enable it if necessary. The kernel tree path is on boot The FirmataC library and exam- Device Drivers > GPIO Support There’s a place on the kernel to load ples are made by jdourlens, which > /sys/class/gpio/... (sysfs modules as needed. However, you can’t use were slightly modified for use on the interface) it to send echo commands or values to sysfs ODROID: https://github. If you embed the driver, you can without root or super-user permissions. com/jdourlens/FirmataC access the GPIO via the kernel node / Fortunately, there is a way to overcome this
ODROID MAGAZINE 33 TECHNICAL ARTICLE Using an ODROID-XU as a Wifi Router get to 802.11ac with style by Mauro Ribeiro, Hardkernel Developer
f you’d like to use your ODROID- XU as a wireless router, you’ll need Ithe following items, all of which are available from the Hardkernel website:
ODROID-XU (+E or Lite) Believe us, this USB 3.0 to Gigabit LAN Adapter setup means business MicroUSB 3.0 to USB OTG Cable
USB 3.0 to 802.11ac Adapter make modules_install The LAN Interface is eth1 (Gigabit Adapter) cp arch/arm/boot/zImage /me- microSD or eMMC with Ubuntu Server in- dia/boot stalled The WAN Interface is eth0 (Connected to the internet) sync && reboot The ODROID-XU works best for this project because it offers a USB 3.0 The Wifi Interface is wlan2 This builds a new -XU kernel from port, so that we can use the full band- the latest GitHub source code. Now you width of it for Wifi AC, and because the Although unlikely, the Wifi interface have an updated copy of the kernel on XU models also permit the use of the value (the last item on the list) may be dif- your ARM Board! USB 3.0 Gigabit LAN adapter. For best ferent for your LAN, but this is covered throughput, we’ll use our 10/100 On- below. It’s also very important for secu- Dealing with Realtek Wifi drivers. board LAN as the WAN Port. rity that you change both the root pass- Realtek wifi drivers are slightly tricky The USB 3.0 to Wifi adapter used in word and the “odroid” user password, in to configure: thie article is a Netis WF2190, which case the board is exposed to the internet. Use the provided drivers is based on the Realtek 8812AU chip. Netis ships a mini-cd with the If you have problems finding the Netis Install the necessary packages Linux drivers inside. You’ll have a WF2190 Adapter, there is a listof equiv- and dependencies linux folder with the following fold- alent adapters using the same chip here: er: RTL8812AU_8821AU_linux_ http://goo.gl/dNwdnY. apt-get install git build-es- Before starting, make sure that you sential bridge-utils v4.2.0_6952.20130315. Copy that have at least 4GB of free disk space. The folder to your ODROID, since these are following values are used in this tutorial Build the kernel the drivers that we need to build. for example purposes (your local net- Build the wifi drivers work may differ): git clone --depth 0 https:// github.com/hardkernel/linux. git -b odroidxu-3.4.y linux cd RTL8812AU_8821AU_linux_ The LAN address will be 10.10.10.0/24 v4.2.0_6952.20130315/driver cd linux The LAN gateway (ODROID) will be tar zxvf rtl8812AU_8821AU_ 10.10.10.254 make odroidxu_ubuntu_defcon- linux_v4.2.0_6952.20130315. fig tar.gz The DHCP Range will be 10.10.10.1 to 10.10.10.253 make -j5 cd rtl8812AU_8821AU_linux_ v4.2.0_6952.20130315
ODROID MAGAZINE 34 TECHNICAL ARTICLE
* edit the Makefile and on line 583 ARCH ?= .... change to ARCH ?= arm cd RTL8812AU_8821AU_linux_ iface br0 inet static v4.2.0_6952.20130315 bridge_ports eth1 make && make install cd wpa_supplicant_hostapd address 10.10.10.254 modprobe 8821au cd wpa_supplicant_hostapd- 0.8_rtw_r6747.20130222 netmask 255.255.255.0 Now your Wifi drivers should be working properly. cd wpa_supplicant network 10.10.10.0 pre-up /sbin/ifconfig wlan2 Test the Wifi Driver Again, we have to make sure that up Ubuntu’s wpa_supplicant isn’t present: ifconfig wlan0 up After rebooting, your LAN interface will apt-get remove wpasupplicant iwlist wlan0 scan be called br0 with eth1 being part of it. make && make install Note that if wlan0 doesn’t exist, check Using hostapd for wlan1 or wlan2 by typing “ifconfig This installs all of our wifi drivers, Since the wireless adapter doesn’t -a”. Save this information for later, be- along with the manufacturer’s provided have dual radios, you have to choose be- cause we’ll need to know the wifi card tools. Let’s move on into the configura- tween the 5GHz or 2.4Ghz frequency. name in an upcoming step. tion part. If you are on a network with only 5Ghz At this point, you’ll see the list of devices, which most are nowadays, use Wifi networks in Range. You can now Configuration the 5Ghz config to allow a maximum use your ODROID as a Wifi client to The Ubuntu Network Bridge must speed of 800Mb/s. If you need extra connect to other wireless networks. be configured in order to create the inte- compatibility with older computers, or gration between the Wireless and Wired your devices aren’t 5Ghz, use the 2.4Ghz Building hostapd connections. configuration shown below. and wpa_supplicant To begin configuring the hostapd cd /etc/network service, start by creating the following Because Realtek 8812 isn’t supported file using root privileges: on Linux yet, we need to build the driv- You’ll also need to edit the interfaces ers, including hostapd, from the manu- file, using the following screenshot as an /etc/hostapd.conf: example: facturer’s source provided on their web- 5GHz version site. -- BEGIN -- # Change this to match your Build hostapd config # setup loopback interface from the manufacturer’s source interface=wlan2 auto lo cd RTL8812AU_8821AU_linux_ ctrl_interface=/var/run/hos- v4.2.0_6952.20130315/wpa_ iface lo inet loopback tapd supplicant_hostapd # setup eth0 as DHCP for our # Your network name tar zxvf wpa_supplicant_hos- WAN tapd-0.8_rtw_r6747.20130222. ssid=ODROID-NET 5Ghz tar.gz auto eth0 channel=36 cd wpa_supplicant_hostapd- iface eth0 inet dhcp 0.8_rtw_r6747.20130222/hos- wpa=2 tapd # setup eth1 as manual and leave it empty # Your network password
Before building and installing ho- auto eth1 stapd, let’s just make sure that we don’t wpa_passphrase=testtest have Ubuntu’s hostapd installed: iface eth1 inet manual bridge=br0
apt-get remove hostapd # Create our bridge with eap_server=0 eth1 on it and use the IP make && make install 10.10.10.254 wps_state=0 auto br0 Building wpa_supplicant driver=rtl871xdrv
ODROID MAGAZINE 35 TECHNICAL ARTICLE
beacon_int=100 Now that our devices can connect /usr/local/bin/hostapd /etc/ to our new network, they need to be hw_mode=a hostapd.conf & able to access the internet. We’ll fix that right now! ieee80211n=1 sleep 3
wme_enabled=1 /sbin/brctl addif br0 wlan2 Creating IP tables for internet access ht_capab=[SHORT-GI-20] DNS and DHCP Edit /etc/rc.local, and before [SHORT-GI-40][HT40+] Our network needs both a DNS and “exit 0”, add the following lines: wpa_key_mgmt=WPA-PSK a DHCP Server in order to auto-con- figure our clients. In this case, we’ll use echo 1 > /proc/sys/net/ wpa_pairwise=CCMP dnsmasq since we already installed it as a ipv4/ip_forward dependency in the first step. max_num_sta=8 iptables -t nat -A POSTROUT- ING -s 10.10.10.0/24 -o wpa_group_rekey=86400 - mkdir /etc/dnsmasq eth0 -j MASQUERADE 2.4GHz version Create the file/etc/dnsmasq.d/ odroid.conf: Now we’re done, and you should interface=wlan2 have a fully functional wireless router.
ctrl_interface=/var/run/hos- resolv-file=/etc/resolv.dns- tapd masq
ssid=ODROID-NET 2.4Ghz addn-hosts=/etc/dnsmasq/ hosts
channel=6 dhcp-hostsfile=/etc/dnsmasq/ dhcp wpa=2 expand-hosts wpa_passphrase=testtest min-port=4096 eap_server=0 stop-dns-rebind wps_state=0 rebind-localhost-ok driver=rtl871xdrv interface=br0 beacon_int=100 LAN Utility showing # Here on this line we’ll that the router is up hw_mode=g configure the LAN interface and running (br0), initial IP Address ieee80211n=1 # last IP address, Network wme_enabled=1 netmask and the time that a To make your router even more IP will be kept to a client useful, you can also attach USB ht_capab=[SHORT-GI-20] disks to the USB 2.0 ports of the [SHORT-GI-40][HT40+] # that is known as lease time ODROID-XU, then create a Torrent wpa_key_mgmt=WPA-PSK server, a Samba file server, or any oth- dhcp-range=tag:br0,10.10.10. er type of shared network resource. wpa_pairwise=CCMP 1,10.10.10.253,255.255.255.0 ,1440m I’ve tested the ODROID-XU router max_num_sta=8 with my Nexus 5 phone, and it report- # This line we configured the ed a throughput of 433Mb/s. That’s wpa_group_rekey=86400 IP address of our gateway quite nice for Wifi, isn’t it ? It could (the odroid) go faster, but I think that 433Mb/s is a You should customize the interface dhcp-option= limitation of the Nexus 5. parameters “ssid” and “wpa_passphrase” tag:br0,3,10.10.10.254 for your network. dhcp-lease-max=255 Next month, I’ll discuss how to setup some attractive graphics to monitor Auto-Start hostapd dhcp-authoritative Edit /etc/rc.local and add the the input/output data on your net- following lines before the “exit 0” line: work. ODROID MAGAZINE 36 Setting up a 1080p Home Media Center The Art of Multi-boxing 1080p Home Media Center using Pocket Rocket and Whisper by Rob Roy, Chief Editor A pair of ODROID U3s can run all of this!
ulti-boxing is an advanced net- Using a second system to do the work of and another Odroid as the media client. working technique of connect- gathering media files then frees up the Since XBMC for Android gives the best Ming two or more computers to main system for playing smooth video performance in 1920x1080 resolution, create a single virtual system. Originally without glitches caused by spikes in disk I chose Android Pocket Rocket as the referring to gamers who dominated on- activity. client, which already has the necessary line matches by controlling several players To illustrate the concept of Odroid SSH, VNC, and Samba protocols in- simultaneously, the methods can also be multi-boxing, two of the community stalled. For the media server, Lubuntu used in other applications besides gam- images available on the Odroid forums, Whisper works well because of the pre- ing as a way to use parallel computing to Android Pocket Rocket and Lubuntu configured Desktop Sharing, Transmis- improve the overall responsiveness of the Whisper, can work cooperatively to sion and Samba applications. Both user experience. run two Odroids as a virtual octa-core images are available for download from Compared to a single-box system, system. Operating two images simul- the Odroid forums at http://forum. which requires a reboot to switch be- taneously improves the stability and ef- odroid.com/. tween platforms, the key combination ficiency of both environments, with the In this dual-box system, media ac- Alt-Tab switches between the different advantage of doubling the computing quisition is performed only by the Linux desktops of the multi-boxed machines. power, RAM and disk storage available server, which can elegantly handle a high Tasks that would normally slow down for use. Alternatively, the full-featured volume of disk and ethernet activity. the user interface, such as downloading, Dream Machine image may be used in- When media files are ready for viewing, video conversion, or torrents, are moved stead of Whisper, and the Couch Potato the Android system loads them from to a second computer which performs SD card image may be substituted for a common shared directory and plays its job seamlessly in the background, Pocket Rocket in case an eMMC mod- them using a hardware-decoded video but appears on the first machine as if it ule is not available. player like XBMC or MXPlayer. were a native application. As a multiple The first step, after downloading and Odroid owner, it’s more economical to Gathering copying the images to an eMMC mod- connect several Odroids together, ac- the Equipment ule or SD card, is to set up the network cessed by a single monitor and keyboard, Setting up an Odroid multi-boxed neighborhood so that the Odroids can than to purchase separate equipment for virtual computer requires any two find each other. each computer. Odroids from the X, U or XU series, The primary advantage of delegating and a modern wi-fi router. The remov- Configuring tasks among several computers is that, if able eMMC modules available from the Router disk or CPU activity is high on one ma- Hardkernel give the best disk perfor- The server system running Whisper chine, the performance of the other sys- mance, and for media storage, a high- needs a local static IP address so that the tems are unaffected, since each comput- capacity external USB drive or SD card other Odroid can locate it on the net- er has its own local resources, without permits sharing of large files between work easily. Without a static IP, the con- needing to compete for processor cycles the computers without crowding the nections would need to be reconfigured or hard drive access. For example, when main operating system partition. with a new IP address after each reboot. watching videos, heavy background The following guide outlines the The option to assign a permanent IP downloading can affect the frame rate of steps necessary for building a typical address, also called DHCP reservation, the video playback, causing video arti- Home Media Center with two Odroids, is included in the wi-fi router’s admin- facts, frame stuttering and audio delays. using one Odroid as the media server istrative panel. For example, using a ODROID MAGAZINE 37 Setting up a 1080p Home Media Center
admin panel and setting a With SSH, remote commands may be static IP address. sent to the server using the standard To reserve the static IP ad- command line interface to start and stop dress, boot up Whisper with applications, reboot the system, and per- its ethernet port connected form other administrative functions. In to the router, then login to the media center example below, it will the router from any comput- be used to launch the VNC server. er on the network. Follow Samba is a free software implementa- the manufacturer’s instruc- tion of the SMB/CIFS networking pro- tions, setting the static IP ad- tocol, allowing remote file servers to be dress for the Odroid running mounted as local drives. For purposes Whisper to a convenient and of media sharing, the Samba server en- easy-to-remember number, ables video, audio and other files to be such as 192.168.1.100. accessed by the Android media client via the ethernet port. Enabling To improve system security, all three Desktop protocols require separate usernames Sharing, and passwords. For convenience, Sam- Typical router admin panel with option Samba and ba, SSH and VNC are initially synchro- to assign static IP address SSH nized to use “odroid” as the username and password. These passwords should standard home Cisco router, the admin The two Odroid have three chan- be changed before moving on to the next page is accessed at 192.168.1.1 with a nels of communication with each other, step, but in the following screenshots, default blank username and password of known as protocols. Each protocol pro- the security remains unedited and all “admin”. Some routers use 192.168.0.1, vides a different service to allow specific password fields contain the default value 10.0.0.1 or another similar address in- types of remote access to the host server’s of “odroid”. stead. For specific instructions, refer disk, memory and peripheral resources: VNC Setting Up to the router manufacturer’s website or stands for Virtual Network user manual for details on accessing the Computing, a protocol that broadcasts the Server a graphical desktop to a remote system For the initial setup, connect the and processes input from the remote Odroid running Whisper to the key- Router admin panel with “odroid” client added keyboard and mouse as if they were con- board, mouse and monitor. Enable to DHCP reservation list as 192.168.1.100 nected locally. VNC servers Desktop Sharing by selecting “Desktop and clients are available for Sharing” from the “Internet” menu, and nearly all modern operat- matching the options to those shown ing systems, including iOS, below. Choose an appropriately secure Android, Windows, Linux password for desktop access which will and OSX. Its wide appeal later be used in setting up the Android permits unique combina- bVNCFree client. tions like accessing a Win- Desktop Sharing configuration menu dows desktop from a Ma- cintosh, running a Linux desktop from within Win- dows, or wirelessly control- ling multiple Odroids from an Android phone or iPad. SSH is a Secure SHell which creates an encrypted text-based connection be- tween two computers us- ing a networked terminal.
ODROID MAGAZINE 38 Setting up a 1080p Home Media Center
tory to “/home/odroid/Downloads” since this is the default save direc- tory for Transmission, Firefox and Chromium. If using an external USB drive, configure all three ap- plications to save to a shared Samba shared storage directory located on the external drive. Output of ifconfig command on Setting Up the Whisper server the Client Now that the server is ready, dis- As a double-check, verify that the IP connect the keyboard, mouse and address of the Whisper system matches monitor, and connect them to the the one selected in the DHCP Reserva- Android Pocket Rocket client ma- tion router setup by running Terminal chine. From now on, the Whisper from the Whisper desktop and typing server will not need any peripherals ex- Pocket Rocket desktop contains JuiceSSH “ifconfig”. If the addresses don’t match, cept in the case of network or router fail- and bVNCFree, make good use of them it may be necessary to reboot Whisper ure. The server’s desktop, command line in order to register it under the new IP interface, files, and CPU are all available Connecting the address stored in the router. to the Android Pocket Rocket client via Finally, connect any large-capacity the the SSH, VNC and Samba proto- Client to the Server device to use as a shared directory for cols. Launch JuiceSSH and select “Man- media files such as an external USB drive The initial connection between the two age Your Connections”, and match the to the Whisper server, and run the “Sam- computers is via SSH, so that the VNC options shown in below figures, using ba” applet from the “Preferences” menu. desktop server may be started, which then the static IP address registered with the Match the options shown in Figures 5-8, allows the X11 desktop to be shared. After router in the first step. Advanced users substituting the preferred storage direc- the Vino server loads, JuiceSSH remains may skip the SSH step by adding Vino tory for the one shown in the screenshot. in the background while the Android ap- as a Linux startup task. For the purposes of running the stress plication called bVNCFree gives remote tests detailed below, set the shared direc- control of the Whisper desktop.
Configuring the Samba options in Whisper
JuiceSSH configuration options
ODROID MAGAZINE 39 Setting up a 1080p Home Media Center
Connecting with VNC Launch the bVNCFree application, and select “New Connection”. Match the configuration options to those shown in Figure 8, again using the static IP address registered with the router and used when setting up JuiceSSH.
Juice SSH connecting to the Whisper server
Android has many built-in shortcut key Configuration options for bVNCFree Once the server is connected, Juic- combinations that closely resemble eSSH drops into the remote server’s those used in Windows and OSX. After the handshake has been estab- scripting shell, known as the command lished, the Whisper desktop opens up, line interface or command prompt. Esc: Close a popup window allowing the Android client to take full For convenience, Whisper includes a control of its storage, CPU and resourc- local Vino script which automatically Control-W: Close the current window es. By also enabling the “Fit To Screen” shares the current desktop using a sin- Control-T: Open a new browser tab scaling option, the virtual system gives gle command. Launch the VNC server the appearance that the server desktop by typing “vino” at the SSH command Control-C: Copy is running natively on the local Odroid prompt, and entering the root password client while simultaneously running An- of “odroid”. Control-X: Cut droid applications. Control-V: Paste Running the Media Control-A: Select all Server Now that the two systems are connect- Tab: Navigate to next input field ed, they are ready to perform some tough Alt-Tab: Switch to another appli- tasks to show off how well the networked cation machines handle a high volume of disk I/O. For comparison, Pocket Rocket will Alt-Tab -> Alt-Esc: Return to the JuiceSSH after running the “vino” command do all of the work on its own as an example desktop (same as Home button) of single-boxing. By stress testing the cli- Mouse Right-click: Go to previous window or close ent system, the areas of improvement be- a popup window if there’s one open come more apparent when many large files Keyboarding are processed at the same time. Like a Pro As an example of keyboard naviga- For the single-box test, download sev- Before moving on to using the graph- tion, you can press Alt-Tab, then Alt-Es- eral files, start a few torrents, and watch an ical X11 desktop, it’s important to be- cape to get back to the Android desktop XBMC video using only Pocket Rocket. come comfortable with the Android instead of clicking on the Home button Although the Android system performs interface itself. To optimize the user with the mouse from within any An- well under medium to heavy load, there experience, Android provides several droid application. will be brief moments during video play- keyboard shortcuts that permit quick back where the screen will stutter, or the window management and data sharing audio will be out-of-sync due to spikes in functions while also alleviating the need disk access. Because the eMMC or exter- for using the mouse. The Alt-Tab menu in Android Pocket Rocket
ODROID MAGAZINE 40 Setting up a 1080p Home Media Center
forms better than the single-box version because of its compartmentalized use of each system’s peripherals. Files may also be copied and shared from one system to another using ES File Explorer, so that documents may be edited locally on the Android client system while maintaining a read-only master copy on the Whisper server. Ad- ditionally, bVNCFree allows text data to be transferred between previously unconnected desktop environments (ex. between Windows and Linux) us- ing the Copy and Paste function of the The Whisper desktop, as viewed through the Android bVNCFree application Android desktop, instead of resorting to an intermediate file or email. nal drive has many applications competing for storage, the playback experience gets Building slightly degraded at random intervals due a Cluster of Odroids to locked resources. Follow the steps again to connect To improve stability and video play- more computers to the cluster, with a back, the tasks of downloading and han- separate SSH and VNC session control- dling high volumes of disk access are ling each additional system. For my per- sonal multi-boxing system, I connected delegated to the Whisper server in the ES File Explorer’s LAN tab dual-box setup. This separation frees up several Odroid computers which offer a the processor cycles and disk usage on the dedicated web server, application devel- Android client so that the video player isn’t the Whisper server allows the videos to opment packages, and a security testing waiting for another application to finish play smoothly on Android, without stut- suite, all operating in their own resource before loading the next piece of the video tering or momentary freezing. The play- spaces, coordinated using the Android from the hard drive. back on the Android client remains con- Pocket Rocket desktop. In order to perform the dual-box stress sistent despite heavy stress,on the server, test, shut down all of the downloads and which grealy improves the experience of Advanced torrents on the Android system so that using Pocket Rocket by itself. Multi-boxing only the video player is running. Press Seasoned Linux users can add auto- Alt-Tab to switch to the bVNCFree ap- Peeking mation to the Media Center by sched- plication, then use the Whisper desktop Under the Hood uling cron jobs, adding RSS feeds, and to download several large files and torrent Since the Android operating sys- kickstarting downloads using the rTor- a few more, using the web browser and tem and video player have no compe- rent command line interface. Further Transmission. tition for the local hard drive, overall customizations include enabling the web After one of the media files has finished performance improves on the Android interface in XBMC and Transmission for downloading, press Alt-Tab to switch to client since it has immediate access to true remote management, and installing the Android video player, such as XBMC, the hard disk, now that the media files a local Apache website for managing, then play the file from the newly added streams have been moved over to the sorting and displaying the media library Samba shared directory. ethernet port. The result of the coordi- contents in an easy-to-read format. The simplest way to load a media file, nation between the two systems is that Handbrake has also recently been ported is to log into the Samba share using either the Android client remains responsive to the Odroid, which can be included in ES File Explorer’s “LAN” tab and single- at all times, while the Whisper server the download process for converting me- click a media file from the shared directory, accomodates the increased disk activity dia files to the preferred resolution and or by starting XBMC and logging into the in the background without locking the codec before making them available to Samba share using the XBMC interface. Android system’s resources. The dual- the Android client. Notice that moving the downloads to box version of the Media Center per- ODROID MAGAZINE 41 MEET AN ODROIDIAN meet an odroidian Mauro Ribeiro: The Software Genius Behind Odroid’s Linux Kernels edited by Rob Roy
What is your official title and role at awesome 386 comput- Hardkernel? er. I still recall the ex- Senior Software Engineer, I mainly act specs” 386-DX40, do Kernel work, Linux Support and deal 4MB of RAM, VGA with our forums. Trying to get onto the Card, 14” Color Moni- Hardware world too.. Its a lot of fun :) tor (CRT), Dual Floppy 5 1/2 and 3 1/4. And As one of the moderators of the ODROID an outstanding 260MB forums, what do you like most about the Seagate HDD. I kept ODROID community? this machine. The CRT I think that what I like most the is and HDD are dead, but amount of information that we managed everything else works. to share and how many users that we had I really got into with no Linux knowledge, now they are Linux in 1998. A friend Mauro dressed in a typical korean attire, a quite advanced. of mine brought me a CD-ROM from cool memento of his last korean trip. USA containing “Slackware 97”. That is How did you get started with computers? where everything started. Since I was 2 years old (from what I room using 5 10W leds. Right now I can remember), I’ve shown a tendency in What are some of your favorite projects have it about 70% complete. Minor bits dealing with electric and electronic stuff. that you’ve seen ODROIDs being used are missing, such as cabling, housing and Mostly because of my uncle’s influence, for? remote control Software. who taught me basic electronics since I I love projects that deal with light was kid. I was 5 or 6 years old when my control and ambiance light control. I What other interest and hobbies do you uncle showed me an Apple 2+. From a don’t think I have seen any of those so far enjoy? friend of his. This was on 1989 or 1990. using ODROID’s. I’ve seen some pret- Race Cars are probably what I love A year later, my uncle gave me an ty neat robots powered by ODROID’s, most apart from the computer side. I’ve and I’m on my own been part of the scene dealing with cars personal project to do ECU’s. Combustion engines are fun. some light control with About my dogs: They are two Lhasa- ODROID’s :) Apso. Meg is the older, she’s 6 years old now.Junior is the last born of her mother, Do you have any per- he’s 4 years old now. Laika and Res were sonal projects that my very first dogs. They are the couple you’re working on using that gave birth to all of my current dogs. ODROIDs? Unfortunately, Laika passed away early Yes, ambient light last year due to complications of a sur- control. It’s using a gery to remove stones on her bladder. Res U3+Shield board to sadly passed away a couple months later. control the light on my Laika died at age 7 ,and Res died at age 9. ODROID MAGAZINE 42