Projects on the Move
Total Page:16
File Type:pdf, Size:1020Kb
Free Software Projects COMMUNITY An up-to-date look at free software and its makers PROJECTS ON THE MOVE Although a couple of scratches are visible, you can read from the backup CD. The question is, for how long? Cdck measures the sector access times to give you an idea. Have you overwritten the bootloader on your disk? Super Grub Disk to the rescue! BY PETER KREUSSEL AND MARTIN LOSCHWITZ Ds and DVDs use optical struc- If you have a big collection of CDs, Depending on the quantity of data de- tures of approximately 100 nano- like the program’s author, Alexey Seme- stroyed by the scratch, the drive has to Cmeters to store data. Even tiny noff, and do not want to create backups read farther ahead to reconstruct the scratches can destroy large numbers of of all your CDs and DVDs but still want data. It takes longer to retrieve the data data bits, without the user even noticing to avoid losing critical data, you need a for a block, even in the case of modern at first. Data redundancy and error-cor- tool that can check the state of your drives with cache memory. Semenoff’s recting techniques, such as cross-inter- disks for you. statistical observations provide empirical leaved Reed-Solomon code, support Semenoff’s program, cdck [1], does a evidence that read errors typically occur error-free data reading, despite damage low-level read of the media and mea- in sectors for which access times were to parts of the disk. Even newly burned sures how long it takes to get the data, high in previous measurements. media might not be free of errors: de- block by block. Error-correction tech- pending on how well (or how badly) niques for optical media work in such a Detailed Test Report your burning device supports your way that the time it takes to access data After testing a medium, cdck displays a choice of media, the disks could have is a metric for the number of read errors report. CD overall lists hard read errors, unreadable sectors right from the outset. that need correcting. Correction tech- which are indicative of data loss. If data niques use a combination of parity bits loss has not yet occurred, the CD Timing Disk Check and interleaving, which is the distribu- values are of interest. Cdck lists the min- It would be nice to know how much of tion of successive bits across the surface imum, maximum, and average access the existing redundancy has already of the CD. If the data bits were stored times for reading CD or DVD sectors. been used up, or how grave the danger sequentially on the disk, parity checks To let non-experts interpret the report, of imminent data loss is. The test func- would not serve any useful purpose. Be- cdck sums up the output with a clear tions that many burning tools use for cause of the minuteness of the recesses message: CD is excellent (for read times media verification are not a big help. on the disk, scratches would always of less than 0.1 seconds throughout), CD The functions only check whether the destroy contiguous bits, which is not is satisfactory (between 0.1 and 1 sec- filesystem is legible after applying error- typically the case when data is scattered ond), or CD is unstable (access times correction techniques. across the disk. greater than 1 second). Setting the -p WWW.LINUX - MAGAZINE.COM ISSUE 78 MAY 2007 91 COMMUNITY Free Software Projects Super Grub The Installer team has done desktop Disk’s prowess is users a big favor by providing a GUI. Al- not restricted to though the graphical installation process temporary fixes. is far removed from tools like YaST2, the The tool will rein- framebuffer methods it implements give stall Grub and less experienced users the option of LILO, both in the clicking to install, rather than relying on Master Boot Re- the keyboard. cord and in the Also, a number of minor bugs that be- boot sector on came apparent after the release of Sarge certain partition have been removed from the Debian types. Besides Installer in the normal course of the re- Figure 1: Red bars in the graphic indicate CD or DVD sectors with this, the live disk lease cycle and version update. above-average read times. Data loss is probable. can help you solve issues, such Secure APT option tells the tool to create a logfile, as setting the boot flag for the primary Users and administrators alike have been which you can visualize in Gnuplot [2] partition, that occur when booting Win- looking forward to Debian APT validat- (Figure 1). dows. Super Grub Disk can boot Win- ing package sources for quite awhile. Up The red bars in the graphic represent dows with Grub’s chainloader option, or until the Sarge release, malevolent hack- sectors with unusually long access by writing a generic entry to the Master ers could manipulate packages and foist times. The figure also shows the read Boot Record and flagging the Windows them on unexperienced Debian users. speed of the drive increasing; this has partition as active for the boot process. Etch changes this – the Secure APT tool nothing to do with the quality of the me- Because Super Grub Disk gives users uses a package list with GPG signatures dium, but with the increasing angular without Linux skills the ability to install to make sure the download really is a velocity. Grub, the developers recommend the Debian package. If the package fails to tool to Windows users who need a re- validate, APT refuses to install it. Super Grub Disk placement for the less-than-flexible Win- Murphy’s Law dictates that if things can dows bootloader. Besides Windows, the Debian for Servers go wrong – like overwriting the boot- admin tool will also reanimate GNU Debian has always had an excellent rep- loader on your disk – they will go Hurd and OpenSolaris kernels. utation as a server operating system, and wrong, especially when you’re in a Of course, Super Grub Disk doesn’t ac- Etch continues in the same vein. If you hurry. Even the most experienced ad- tually do anything a system administra- install a database like MySQL or Post- ministrators want a tool to handle what tor couldn’t do manually, but the practi- greSQL, the dbconfig-common utility would otherwise be a manual task at the cal tool does save time and headaches. helps out by providing a standardized spartan Grub command line. Super Grub A footprint of just less than 3MB means front-end. The utility also supports Disk [3] is an ISO image that weighs in that Super Grub Disk will fit on any USB seamless integration of packages that at about 3MB, with its functionality stick, and thus in your pocket. need to access the database to work based on Grub. After burning the image properly, removing the need for adminis- to a CD or installing the tool on a USB Etch trators to fulfill database dependencies. stick [4], you can boot a rescue system We know that Debian 4.0 – or Etch – has The new release sees a change in the (Figure 2). now been frozen and new features are standard character set to UTF-8 and uses no longer being accepted, but we don’t udev in combination with kernel 2.6. Search, Find, Fix know whether Etch will have been re- Super Grub Disk saves you having to leased by the time this issue of Linux Pro Debian for Desktops guess the name your distribution’s ker- Magazine hits the stores. A peek at the Gustavo Franco, the Debian Desktop nel image uses on the disk. The live sys- new features in version 4.0 and what ad- project maintainer, made liberal use of tem automatically searches for the Grub ministrators and users can expect is still superlatives when referring to Etch as configuration files. a good idea [5]. the “user-friendliest” Debian of all time. Users can either specify the partition Debian has ignored the desktop market with /boot/grub, or – if you did not set Installation for far too long, which is probably one of up the system yourself – leave the tool The installation breaks with old tradi- the reasons users are moving to Ubuntu. to its own devices, without wasting any tions – the base-config script (the legacy Mark Shuttleworth’s Ubuntu team time guessing. tool for the initial system configuration) clearly targeted the desktop as the focus If the boot issue is caused by a faulty has been dropped. Instead, the develop- of development work on the distribution or missing Grub configuration file, the ers have integrated the initialization from the outset. software will alternatively check the phase with the installer to create a uni- To make Debian more accessible to /boot directory for kernel images and fied tool. This is the first version to let users, the new version adds a number of boot the images without parsing the users create encrypted partitions during changes. KDE and Gnome have both menu.lst file. the install. been customized to reflect the Debian 92 ISSUE 78 MAY 2007 WWW.LINUX - MAGAZINE.COM Free Software Projects COMMUNITY look, but without both desktops looking for example, typing debtags related zsh major battles that have accompanied the exactly the same. In contrast to Sarge, will give you the results. Etch release thus far. For example, Jörg Etch now gives users the option of se- In contrast to the former classification Schilling pushed Debian too far with lecting Gnome or KDE during the instal- in sections, or searching the package de- machinations concerning the Cdrecord lation phase and booting into the desk- scriptions, Debtags searching is efficient; license to such an extent that Debian fi- top right after completing the installa- however, not all packages have tags, so nally decided to fork an older version of tion.