EMerlin Repeater Station PC (RPC) P. Burgess, Jodrell Bank Observatory 05/Feb/2004 (V1.3) Last Revision: 2008-10-13 v2.0 new OS 1.Introduction. The Repeater PC is a straightforward ‘minimal’ PC for monitoring eMerlin fibre- optic repeater stations. It is intended normally to be accessed by dial-up modem. A local keyboard and display is provided. The unit operates under the Linux operating system. This document provides sufficient information to rebuild a system from scratch, although normally it will be provided set up. 2. Design Requirements: • Support Linux and dial-up modem, plus additional serial ports. • Provide simple on-site display and keyboard • Low cost and maintenance • Sustainable upgrade path to hardware changes These requirements may be met by a simple combination of off-the-shelf motherboard, CPU and memory components. Although very small single-board PCs are available, space is not at a premium, so a commercial 4Ux19in. rack mount case has been chosen. This case includes a keyboard and VGA (640x480) colour display. The additional cost of this hardware (most of the cost of the complete unit in fact) is justified by convenience and robustness. Jodrell VLBI has experience with Asus motherboards and AMD CPUs and finds them well-supported. We have attempted to select devices with known Linux compatibility. Choice of Modem: There is a problem using internal modems under Linux. Most internal cards are now so-called ‘Winmodems’, i.e. they have minimal (or no) controller hardware, and requires Windows to replace it. There are a small number of devices which do have internal hardware, usually known as ‘Linmodems’,which have drivers, or may be configured, for Linux. After a series of tests we found the Sitecom DC-015 56kbps internal V92 (www.sitecom.com) modem to be reliable. 3. Software Requirements The requirement is for both operating system and user software to be maintainable by ourselves at minimum cost. At the moment Jodrell has adopted the Linux system for its outstation control work as it is open-sourced, robust and predictable and does not incur license fees. There are numerous ‘distributions’ of Linux available with quite widely varying levels of detail changes. We require a simple, easily-maintainable one that is likely to be around in some form in the future. The Debian system was selected for its long- term stability, easy package installation, and familiarity. Current release is 'Etch'. 4. Component Specifications Rack Case 4U - Wordsworth EC-1040BATX/832AP wit DM64T display and Main Board - Asus A7N266VME-SE skt A incl. Ethernet Realtek 8201 PHY Nvidia AGP graphics CPU - AMD XP-1800+fan Memory - 256 Mbyte generic DDR SDRAM module Modem - ‘Sitemodem’ DC-015 internal PCI card Hard Drive - 40Gb Maxtor IDE in rack carrier module Cdrom - Samsung internal IDE OEM 5. General Assembly The ATX motherboard installs directly in the rack case. Our version had a slight misalignment between the rear panel opening and the metal plate insert supplied with the motherboard, fixed by slicing one end off the panel. The DM640T (TFT) colour display is designed to fit directly into the left side of the front panel. The supplied VGA cable is used to pass the display connector to the lower rear panel. The connection between the VGA input and and the motherboard video output is completed by a JB-made 15-to-15 way VGA-D connector about 30cm long. The hard drive was installed in a low-cost sliding module rack (Samcheer SC27) in the upper 5-1/4 drive bay space, connected to IDE 0 (master). The cdrom then fits in the middle bay (connect to IDE1), leaving the lowest bay free. The drive jumper should be set to ‘CS’ (Cable Select) for both units – default. (nb some units may be configured with the CD as ‘master’ and the drive as ‘slave’ – check if changing the drives). The modem is located in PCI Slot 2 (centre white slot) The Vscom serial card should be in Slot 3 (outer / furthest from PSU). Slot 1 (nearest PSU) and the brown AGP slot are unused. The integral keyboard and ‘mouse’ touchplate are connected via included mini-DIN (PS/2 style) connectors to the motherboard at the rear panel. There may be a couple of spare ‘sensor’ cables in the case: they may be tied out of the way. Some units were later fitted with a third 9-pin serial port connector on one of the previously-unused card slots, which allows access to the second onboard Com port (Com2/ttyS1). The 25-connector is not used, but could be internally reconnected in place of the 9-pin if needed. 6. Initial Testing Power-up should be performed, checking for correct fan operation and display illumination. The display will normally attempt to configure itself but there is an auto/ manual option on its menu. Check that the BIOS detects the hard drive,floppy drive (if fitted) and cdrom correctly. Power-down again. 7. Installation of Linux Operating System This section describes a ‘from scratch’ installation and may not be needed if an existing system can be copied (See Section 13). Currently we use Slackware Linux 9.1, requiring 2 CD’s. BIOS Settings (required) : (Hit ‘Del’ during startup) (a) ‘Audio’ on-board device set to ‘disabled’ under ‘Chip Config’ menu. (b) ‘MIDI’ port and irq disabled under IO submenu. (Frees up an irq) (c) PCI submenu: set Slot 3 (Vscom board) to IRQ 11; others on ‘auto’ (d) If the USB is not required, it may be disabled under ‘IO’ submenu. (e) Plug-and-Play OS: select ‘No’. (f) Virus Alert: Select ‘Disabled’ Download the Debian Etch Linux installation ISO CD images from a Debian mirror on the Web. The 'netinstall' CD is the best way provided a network connection is available. An ISO image will be placed on newton:/usr3/projects/Repeater. Make a CD’ using ‘Nero’ on the VLBI Windows PC or 'Brasero' (Linux) Boot the RPC with Etch netinstall in CD drive -The install is straightforward: ChooseUS english and keyboard The install should find a DHCP ip address Supply domain 'ast.man.ac.uk' Choose default 'guided' disk partitions with separate 'home' area. Choose a local mirror site (eg ftp.uk.debian.org) For System Type choose 'Standard'; deselect 'Desktop' a minimum non-X system will be installed Accept 'save grub to MBR' 7.1 Updating the Kernel With the current default kernel options, the modem control driver cannot be loaded. The image, headers and source are updated – see Appendix 3 8. Configuring Linux Debian install finds all the components, including the video and network drivers. (An 'X' system can be supported if it is installed) 8.1 TFT Display and Xwindows The unit normally runs remotely or requires only console access. A simple ‘X’ configuration could be available for a 15in. external display or the TFT, although the latter is difficult to use under ‘X’. Debian install 'gnome'. 9. Install and Configure Modem Driver 9.1 HSF Modem Driver (Conexant Chipset) Download the free ‘HSFModem’ package from linuxant.com See: http://www.linuxant.com/drivers/hsf/downloads-license.php File: hsfmodem-7.18.00.03full.tar.gz Download the Debian install package, unzip the '.deb' installer. The kernel image, headers, and extra tools must have been installed, which is easy via 'apt-get': see Appendix 3 Cd to the new directory ‘HSFmodemxxxx..’ Install the driver with 'dpkg -i hsfmodem_<version>.deb Perform the initial configuration stage (hsfconfig: UK) Check that a new device in /dev/has appeared (‘/dev/ttySHSF0’) Check for ‘modem’ link: ls –ls /dev/modem Reboot; 'lsmod' should show two or more 'hsfxxx' modules. To uninstall do ‘make unistall’ in the hsfmmodem source directory 9.2 ‘mgetty’ TTY Driver Download the latest ‘mgetty’ TTY driver for Linux (mgetty-1.1.3?) See ftp://alpha.greenie.net/pub/mgetty/source/. Installation is very easy: 'apt-get install mgetty' Make a new line in ‘/etc/inittab’ to initialise ‘mgetty’. (See Note 2 below) Reboot and use ‘ps ax’ to check an ‘mgetty’ process is active. (See Note 3) 9.3 Testing Dial-Up Test the modem by dialling and logging-in. Provided the ‘ps ax’ display is correct, this system is robust, and any problems are likely to be due to connecting cables. Any PC, laptop or PDA equipped with a standard dial-up modem may be used to test dial-up. The other PC may use either a dedicated terminal program or Windows Hyperterminal with manual dialling: see the user’s manual for the PC to be used. Notes: i. The free ‘Linuxant’ drivers are limited to 14400 baud. If 28000 baud is required it is necessary to purchase a license from Linuxant for each site (at relatively low cost). ii. Example (useable) ‘inittab’ line for ‘mgetty’: # Dialup lines: #d1:12345:respawn:/sbin/agetty -mt60 38400,19200,9600,2400,1200 ttyS0 vt100 d1:23:respawn:/usr/local/sbin/mgetty -s 115200 -p"@ login: " /dev/modem ( - the first line is an example included in the default file). There are a series of config files provided, however these are overridden by the command line parameters in the ‘inittab’ entry. The ‘sendfax’ options are not used and may safely be ignored. iii. Example ‘ps ax’ report for ‘mgetty’: 731 ? S 0:00 /usr/local/sbin/mgetty -s 115200 -p@ login: /dev/modem - once this line is present in the ‘ps ax’ output the system is usable and should be robust. iv. Linux maintains logs in /var/log: see ‘mgetty.modem’ and ‘syslog’ for relevant entries. v. The modem follows the Hayes command set, which is widely documented. It is possible to use ‘kermit’ to talk directly to it and test it if nececssary.