I serien med intervjuer av folk i
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It take all kind of contributions to create a Linux distribution +like Debian Edu / Skolelinux, +and this time I lend the ear to Justin B. Rye, who is listed as a big +contributor to the +Debian +Edu Squeeze release manual. -
Hvem er du, og hva driver du med til daglig?
+Who are you, and how do you spend your days?
-Jeg heter Olav Dahlum, og er frilans oversetter, tester, -prosjektleder og bruker av fri og åpen programvare som -LibreOffice. Jeg er også et av styremedlemmene i FRISK.
+I'm a 44-year-old linguistics graduate living in Edinburgh who has +occasionally been employed as a sysadmin.
-Hvordan kom du i kontakt med Skolelinux-prosjektet?
+How did you get in contact with the Skolelinux/Debian Edu +project?
-Jeg kom i kontakt med prosjektet i 2009, da jeg ble ansatt i -stiftelsen à pne kontorprogram på norsk for å oversette og teste den -norske utgaven av OpenOffice.org. Arbeidet har hele tiden vært -koordinert sammen med Skolelinux, og mange av de samme menneskene er -involvert, så på den måten ble jeg en del av den utvidede -familien.
+I'm neither a developer nor a Skolelinux/Debian Edu user! The only +reason my name's in the credits for the documentation is that I hang +around on debian-l10n-english waiting for people to mention things +they'd like a native English speaker to proofread... So I did a sweep +through the wiki for typos and Norglish and inconsistent spellings of +"localisation".
-Hva er fordelene med Skolelinux slik du ser det?
+What do you see as the advantages of Skolelinux/Debian +Edu?
-Skolelinux handler i likhet med utdanningssektoren om å dele -kunnskap med andre, og det er dette som er hovedstyrken til -prosjektet. Selv om Skolelinux hovedsaklig er involvert i utvikling -av programvare, er det også et sted der man kan utfolde seg uavhengig -av bakgrunn og ferdigheter.
+What do you see as the disadvantages of Skolelinux/Debian +Edu?
-Hva er ulempene med Skolelinux slik du ser det?
+These questions are too hard for me - I don't use it! In fact I +had hardly any contact with I.T. until long after I'd got out of the +education system.
-Liten utbredelse og manglende støtte fra leverandører som leverer -pedagogisk programvare til skolebruk. Kunne kanskje hatt flere -verktøy som letter administrasjonen ytterligere, slik at også mindre -erfarne databrukere kan utføre lett vedlikehold og rutinejobber.
+I can tell you the advantages of Debian for me though: it soaks up +as much of my free time as I want and no more, and lets me do +everything I want a computer for without ever forcing me to spend +money on the latest hardware.
-Hvilken fri programvare bruker du til daglig?
+Which free software do you use daily?
-Jeg er nesten forpliktet til å si at jeg bruker LibreOffice... Jeg -bruker forøvrig frie og åpne operativsystemer basert på -operativsystemkjernen Linux, for tiden openSUSE 12,1 med KDE4. Men -hvis jeg skal dra fram noen flere eksempler så er nok Mozilla Firefox -og Thunderbird to av de jeg bruker mest. I tillegg er jeg en flittig -bruker av OpenSSH, Irssi, Midnight Commander, Git, Subversion, -Translation Toolkit og Super Maryo Chronicles (litt gøy skal man ha, -og med to håndkontroller liggende er det ikke til å unngå).
+I've been using Debian since Rex; popularity-contest says the +software that I use most is xinit, xterm, and xulrunner (in other +words, I use a distinctly retro sort of desktop).
-Hvilken strategi tror du er den rette å bruke for å få -skoler til å ta i bruk fri programvare?
+Which strategy do you believe is the right one to use to +get schools to use free software?
-Vi må få leverandører av pedagogisk programvare med på laget, men -også utvikle vår egen tilpasset det norske markedet. Det er også -mulig å involvere utdanningssektoren direkte i arbeidet, for eksempel -gjennom studentprosjekter der elevene selv er med å utforme -programvare direkte eller indirekte gjennom aktive bidrag. Dette gjør -ikke bare samarbeidet tettere, men fokuset på standarder og friheten -til å velge sin egen løsning vil kanskje stimulere interessen for -framtidig deltakelse i bransjen. Vi som driver med fri og åpen -programvare ønsker oss ikke rene konsumenter, men tenkende og -selvstendige individer som kan være med å skape sin egen fremtid.
+Well, I don't know. I suppose I'd be inclined to try reasoning +with the people who make the decisions, but obviously if that worked +you would hardly need a strategy.
Once in a while my home server have disk problems. Thanks to Linux -Software RAID, I have not lost data yet (but -I was -close this summer :). But once a disk is starting to behave -funny, a practical problem present itself. How to get from the Linux -device name (like /dev/sdd) to something that can be used to identify -the disk when the computer is turned off? In my case I have SATA -disks with a unique ID printed on the label. All I need is a way to -figure out how to query the disk to get the ID out.
- -After fumbling a bit, I -found -that hdparm -I will report the disk serial number, which is -printed on the disk label. The following (almost) one-liner can be -used to look up the ID of all the failed disks:
- -- --for d in $(cat /proc/mdstat |grep '(F)'|tr ' ' "\n"|grep '(F)'|cut -d\[ -f1|sort -u); -do - printf "Failed disk $d: " - hdparm -I /dev/$d |grep 'Serial Num' -done -
Putting it here to make sure I do not have to search for it the -next time, and in case other find it useful.
- -At the moment I have two failing disk. :(
- -- --Failed disk sdd1: Serial Number: WD-WCASJ1860823 -Failed disk sdd2: Serial Number: WD-WCASJ1860823 -Failed disk sde2: Serial Number: WD-WCASJ1840589 -
The last time I had failing disks, I added the serial number on -labels I printed and stuck on the short sides of each disk, to be able -to figure out which disk to take out of the box without having to -remove each disk to look at the physical vendor label. The vendor -label is at the top of the disk, which is hidden when the disks are -mounted inside my box.
- -I really wish the check_linux_raid Nagios plugin for checking Linux -Software RAID in the -nagios-plugins-standard -debian package would look up this value automatically, as it would -make the plugin a lot more useful when my disks fail. At the moment -it only report a failure when there are no more spares left (it really -should warn as soon as a disk is failing), and it do not tell me which -disk(s) is failing when the RAID is running short on disks.
+ +Recently I have spent time with +Skolelinux Drift AS on speeding +up a Debian Edu / Skolelinux +Lenny installation using LTSP diskless workstations, and in the +process I discovered something very surprising. The reason the KDE +menu was responding slow when using it for the first time, was mostly +due to the way KDE find application icons. I discovered that showing +the Multimedia menu would cause more than 20 000 IP packages to be +passed between the LTSP client and the NFS server. Most of these were + +NFS LOOKUP calls, resulting in a NFS3ERR_NOENT response. Because the +ping times between the client and the server were in the range 2-20 +ms, the menus would be very slow. Looking at the strace of kicker in +Lenny (or plasma-desktop i Squeeze - same problem there), I see that +the source of these NFS calls are access(2) system calls for +non-existing files. KDE can do hundreds of access(2) calls to find +one icon file. In my example, just finding the mplayer icon required +around 230 access(2) calls.
+ +The KDE code seem to search for icons using a list of icon +directories, and the list of possible directories is large. In +(almost) each directory, it look for files ending in .png, .svgz, .svg +and .xpm. The result is a very slow KDE menu when /usr/ is NFS +mounted. Showing a single sub menu may result in thousands of NFS +requests. I am not the first one to discover this. I found a +KDE bug report +from 2009 about this problem, and it is still unsolved.
+ +My solution to speed up the KDE menu was to create a package +kde-icon-cache that upon installation will look at all .desktop files +used to generate the KDE menu, find their icons, search the icon paths +for the file that KDE will end up finding at run time, and copying the +icon file to /var/lib/kde-icon-cache/. Finally, I add symlinks to +these icon files in one of the first directories where KDE will look +for them. This cut down the number of file accesses required to find +one icon from several hundred to less than 5, and make the KDE menu +almost instantaneous. I'm not quite sure where to make the package +publicly available, so for now it is only available on request.
+ +The bug report mention that this do not only affect the KDE menu +and icon handling, but also the login process. Not quite sure how to +speed up that part without replacing NFS with for example NBD, and +that is not really an option at the moment.
+ +If you got feedback on this issue, please let us know on debian-edu +(at) lists.debian.org.
New in the Squeeze version of -Debian Edu / Skolelinux is the -ability for clients to automatically configure their proxy settings -based on their environment. We want all systems on the client to use -the WPAD based proxy definition fetched from http://wpad/wpad.dat, to -allow sites to control the proxy setting from a central place and make -sure clients do not have hard coded proxy settings. The schools can -change the global proxy setting by editing -tjener:/etc/debian-edu/www/wpad.dat and the change propagate -to all Debian Edu clients in the network.
- -The problem is that some systems do not understand the WPAD system. -In other words, how do one get from a WPAD file like this (this is a -simple one, they can run arbitrary code):
- -- --function FindProxyForURL(url, host) -{ - if (!isResolvable(host) || - isPlainHostName(host) || - dnsDomainIs(host, ".intern")) - return "DIRECT"; - else - return "PROXY webcache:3128; DIRECT"; -} -
to a proxy setting in the process environment looking like this:
- -- --http_proxy=http://webcache:3128/ -ftp_proxy=http://webcache:3128/ -
To do this conversion I developed a perl script that will execute -the javascript fragment in the WPAD file and return the proxy that -would be used for -http://www.debian.org/, -and insert this extracted proxy URL in /etc/environment and -/etc/apt/apt.conf. The perl script wpad-extract work just -fine in Squeeze, but in Wheezy the library it need to run the -javascript code is no longer -able to build because the C library it depended on is now a C++ -library. I hope someone find a solution to that problem before Wheezy -is frozen. An alternative would be for us to rewrite wpad-extract to -use some other javascript library currently working in Wheezy, but no -known alternative is known at the moment.
- -This automatic proxy system allow the roaming workstation (aka -laptop) setup in Debian Edu/Squeeze to use the proxy when the laptop -is connected to the backbone network in a Debian Edu setup, and to -automatically use any proxy present and announced using the WPAD -feature when it is connected to other networks. And if no proxy is -announced, direct connections will be used instead.
- -Silently using a proxy announced on the network might be a privacy -or security problem. But those controlling DHCP and DNS on a network -could just as easily set up a transparent proxy, and force all HTTP -and FTP connections to use a proxy anyway, so I consider that -distinction to be academic. If you are afraid of using the wrong -proxy, you should avoid connecting to the network in question in the -first place. In Debian Edu, the proxy setup is updated using dhcp and -ifupdown hooks, to make sure the configuration is updated every time -the network setup changes.
- -The WPAD system is documented in a -IETF -draft and a -Wikipedia -page for those that want to learn more.
+ +About two weeks ago, I was interviewed via email about +Debian Edu and Skolelinux by +Bruce Byfield in Linux Weekly News. The result was made public for +non-subscribers today. I am pleased to see liked our Linux solution +for schools. Check out his article +Debian Edu/Skolelinux: A +distribution for education if you want to learn more.