Could not create activity /svn/repo/!svn/act/9526cf2d-4893-4b35-a843-4c0f2d9f8bc6. [500, #0]
could not open dbm files. [500, #120022]
Can't open activity db: APR does not understand this error code [500, #120022]

What did help was:

mkdir repo.new
svnadmin create repo.new
svnadmin dump repo | svnadmin load repo.new
mv repo repo.old
mv repo.new repo

Binary files repo.old/dav/activities and repo/dav/activities differ
diff -rw repo.old/db/current repo/db/current
1c1
< 59 r9 1
---
> 62 ra 1
Only in repo/db/revprops: 60
Only in repo/db/revprops: 61
Only in repo/db/revprops: 62
diff -rw repo.old/db/revs/10 repo/db/revs/10
4c4
< id: aq.0.r10/17
---
> id: e1.0.r10/17
6c6
< pred: aq.0.r8/1443323
---
> pred: e1.0.r8/1443490
16c16
< dir b0.0.r8/1443476
---
> dir av.0.r8/1443643

I don't feel very good about changes, but repository was created with newer version from backports, and this time we used version from etch (thus downgrading from 1.4.6 to 1.4.2).

The whole point of this post is to help some random Google user with downgrade of subversion. So, here you have it!]]> http://blog.rot13.org/2008/06/subversion_downgrade_and_permission_errors.html http://blog.rot13.org/2008/06/subversion_downgrade_and_permission_errors.html howto subversion Tue, 03 Jun 2008 13:25:49 +0100 GROUP BY in my shell pipes. So I wrote one groupby.pl.

Aside from fact that it somewhat looks like perl golfing (which I'm somewhat proud of), let's see how does it look:

dpavlin@llin:~/private/perl$ ps axv | ./groupby.pl 'sum:($6+$7+$8),10,count:10,min:($6+$7+$8),max:($6+$7+$8)' | sort -k1 -nr | head -10 | align
440947 /usr/lib/iceweasel/firefox-bin        1 440947 440947
390913 /usr/sbin/apache2                    11  22207  39875
180943 /usr/bin/X                            1 180943 180943
135279 /usr/bin/pinot-dbus-daemon            1 135279 135279
122254 mocp                                  2  25131  97123
 84887 pinot                                 1  84887  84887
 78279 postgres:                             5  10723  21971
 70030 /usr/bin/perl                         6   6959  15615
 50213 /bin/bash                             7   6351   7343
 49266 /usr/lib/postgresql/8.2/bin/postgres  2  24631  24635

So, let's move to another example, this time for OpenVZ. Let's see how much memory is each virtual machine using (and get number of processes for free):

$ vzps -E axv --no-headers | ./groupby.pl 'sum:($7+$8+$9*1024),1,count:1'
2209504127 0 265
611768242 212024 38
162484775 212037 19
170797534 212052 38
104853258 212226 26
712007227 212253 21

$ vzps -E axv --no-headers | ./groupby.pl 'sum:($7+$8+$9*1024),1,count:1' --join 'sudo vzlist -H -o veid,hostname' --on 2                                 
2146263206 0 259
675835528 saturn.ffzg.hr 40
162484775 arh.rot13.org 19
170797534 koha-dev.rot13.org 38
104853258 koha.ffzg.hr 26
712011323 zemlja.ffzg.hr 21

$ vzps -E axv --no-headers | ./groupby.pl 'sum:($7+$8+$9*1024),1,count:1' --join 'sudo vzlist -H -o veid,hostname' --on 2 | sort -rn | align | ./sum.pl -h
0                  260   2105M OOOOOOOOOOOOOOOOOOO                  2105M
zemlja.ffzg.hr      21    679M OOOOOO-------------------            2784M
saturn.ffzg.hr      35    512M OOOO--------------------------       3296M
koha-dev.rot13.org  38    162M O------------------------------      3459M
arh.rot13.org       19    154M O--------------------------------    3614M
koha.ffzg.hr        26     99M ----------------------------------   3714M

PostgreSQL database size

dpavlin@llin:~$ pg_size dellstore2 | grep -v sql_
4890624 customers 20000
3153920 orderlines 60350
2678784 cust_hist 60350
991232 products 10000
966656 orders 12000
450560 inventory 10000
8192 categories 16
0 reorder 0

Nice console graphs

dpavlin@llin:~$ COLUMNS=80 pg_size dellstore2 | grep -v sql_ | sum.pl -h
customers 20000    4776k OOOOOOOOOOOOOOOO                                 4776k
orderlines 60350   3080k OOOOOOOOOO-----------------                      7856k
cust_hist 60350    2616k OOOOOOOOO---------------------------               10M
products 10000      968k OOO-------------------------------------           11M
orders 12000        944k OOO----------------------------------------        12M
inventory 10000     440k O-------------------------------------------       12M
categories 16      8192b ---------------------------------------------      12M
reorder 0              0 ---------------------------------------------      12M

Let's take another example (if you are still reading this and not interested in PostgreSQL database size). Let's see how much traffic did pppd transfer over very slow GPRS link on 8-day vacation:

dpavlin@llin:~$ grep 'pppd.*: Sent' /var/log/messages | awk '{ print $7 + $10 " " $1 " " $2 }' | sum.pl -h
May 5         0                                                               0
May 5       39k                                                             39k
May 5     7512k OO                                                        7551k
May 6     6352b --                                                        7558k
May 6       20k --                                                        7579k
May 6     1183k ---                                                       8762k
May 8     6869k OO---                                                       15M
May 8       70k -----                                                       15M
May 9     3596k O------                                                     18M
May 9     1998k -------                                                     20M
May 10      32M OOOOOOOOOOOO--------                                        53M
May 10      13k --------------------                                        53M
May 11      44M OOOOOOOOOOOOOOOOO--------------------                       98M
May 12      12M OOOO--------------------------------------                 111M
May 13    7120k OO-------------------------------------------              118M
May 13      20M OOOOOOO----------------------------------------------      139M

As I get only few comments on my blog, if you find this useful, leave one. I have few other examples, like the one which shows top 5 memory eaters on my system:

dpavlin@llin:~$ ps v | awk '{ print $8 " " $9 " " $10 }' | sort -rn | ~/private/perl/sum.pl | head -5
# RSS %MEM COMMAND
10.6 /usr/lib/iceweasel/firefox-bin 165092 OOOOOOOOOOOOOO                165092
4.3 perl                             67240 OOOOOO---------------         232332
0.5 awesome                           8504 ---------------------         240836
0.4 irssi                             6632 ----------------------        247468
0.3 vi                                5888 ----------------------        253356

Because my time is limited, I would like to work in user-land if at all possible, and since wpa_supplicant can work on unmodified kernels, it would be nice to have that level of support for OLPC mash also. After a lot of browsing (and reading few really great wifi hacking sites), I concluded that only hope is radiotap which is more-or-less supported on every pcmcia wifi card that I have (prism based 802.11b card and rt2500). I had also found simpliest possible code which uses radiotap to start with.

Now, I would just need another OLPC to save some network traces and start experimenting :-)

Aside from that, I switched totally to OLPC for this week, and amazingly enough, I didn't miss my Eee PC one tiny bit. Although a bit slower than Eee, OLPC screen is bigger (and better in black and write mode on sunlight) which helps a lot with web pages. Browser performance is amazing, so I have little doubt that we will be able to support most of web sites on OLPC without much problem. OOH, I did notice a couple of excessive round-tips on one of my web sites, while surfing on it, but that's for best anyway :-)

Update: According to message on libertas-dev mail list there is effort to use kernel's 802.11s implementation which makes my effort in supporting OLPC variant obsolete.]]> http://blog.rot13.org/2008/04/state_of_linux_wifi_first_week_with_olpc.html http://blog.rot13.org/2008/04/state_of_linux_wifi_first_week_with_olpc.html hack-of-the-week linux olpc wifi Wed, 30 Apr 2008 00:17:37 +0100 OLPC Croatia in spreading a word and intention of this project. Yesterday we had great presentation in Varaždin and they are interested in pilot project. With news like this it seems that we are fighting windmills. I hope that we are not wrong to invest time and effort into this since my first day of experience with little green thing is very positive. For a start let me clear some doubts: it is slow machine. Keyboard is really different (much worse than Eee PC for example), but if you don't press it harder than needed (which was my problem) it's actually O.K. It's also heavier than Eee PC (which somehow I noticed carrying it around) but other than that it great machine. Having said that, I had problems with associating to my AP (so I used scripts for that), but as a real Linux user, I decided to take a look at it. From that point on, things improved: first i noticed very nice upgrade mechanism with allowed me to upgrade to build 703 which works great. This build is not final, so it comes without any Actions (think of them as applications installed on OLPC), but installation of Action pack from USB stick is really easy (it's also possible to upgrade system using USB stick if you don't have network). The only show-stopper problem that I now have is how to buy OLPC? I don't even know if we can order just 2000 units for pilot program, but I would really love to have ability to buy device for me and other interested developers in CARNet. Having said that, if you do have OLPC which you are not using, it can find new home with interested developer. Aside from that, hi-res black and white screen is just beautiful, machine performs extremely well if you have in mind that it's basically 430Mhz pentium machine with 256Mb or RAM and 1Gb of flash. It seems like too little, but if you use OLPC as network connected digital notebook (with sharing!) it works beautifully. It best mobile device I had since palm back in last century. Every little thing of this machine is designed great: kudos do development team. One small thing is that you can rotate screen in both directions (Toshiba, take note of this!). Hardware keys on both sides of display actually make usage a joy (and decrease a need to touch keyboard). If we from moment move on from hardware to Sugar, it really great user interface which I would love to see on other laptops (before you ask, I did try it on Debian and it does work, I will take another look after I will have to return laptop). I really hope that this project will live on and enable us to deploy units to elementary schools and hopefully achieve some benefit for students (which I'm somehow sure we'll have :-)]]> http://blog.rot13.org/2008/04/first_day_with_olpc.html http://blog.rot13.org/2008/04/first_day_with_olpc.html personal olpc Wed, 23 Apr 2008 16:52:24 +0100 first ever Croatian perl workshop. Thanks to all the people who showed up, we had attendance of about ten. Organizing a workshop event turned out to be much more work then I anticipated, and various other tasks stopped me from preparing for it as good as I should. Also, small number of people force me to re-consider my lectures about perl. On one hand, I really, really, tried to spread perl (and had good fortune of being at right place at right time to get Zagreb.pm off the ground), but with such low attendance, I must conclude that perl is used only by about 20 people in Zagreb. This seems somehow disturbing. Comparing size of Zagreb with Moscow turned out to show about same proportion, so I was just overly optimistic. I also gave half an hour presentation about Jifty, based on Building a Jifty app in a jiffy by Kevin Falcone and showed some examples of my jifty apps (I actually didn't talk about last one, just mentioned it as integration of external javascript -- CodePress in this example). I also have to thank to Andrew Shitov from Moscow.pm who have managed to prepare several very interesting topics which, in my opinion, made this event worthwhile. If it wasn't free I would ask my money back :-\]]> http://blog.rot13.org/2008/04/first_croatian_perl_workshop.html http://blog.rot13.org/2008/04/first_croatian_perl_workshop.html personal Zagreb.pm perl personal Tue, 15 Apr 2008 23:57:41 +0100 existing cpu emulators) and implemented Orao, Galaksija and Galeb using it. Various machines are in different stage of usability. Orao emulation is working (without tape support), Galaksija is too slow to be useful (also doesn't have tape) and Galeb doesn't have keyboard or tape support. I would be very grateful for hardware information about those machines if you can spare some time writing them. I'm somewhat hope that source code of this emulators might serve as historic reference how this machines where constructed. Lately, I have also found mess project, but soon after that I also noticed that I need about six times as much to implement changes in it. C is just not my language, so actually only hope for preservation of those computers is good documentation (which is something mess community is striving also). On the other hand, currently CPU emulation library is not license compatible with GPL so I won't probably push this to CPAN any time soon but I would love to find another implementation (PowerPC anyone?) and basically create thin layer of perl code which can express different architectures. Having written all that now it's time to show you how to compile dam thing!

svn co svn://svn.rot13.org/VRac/
cd VRac
perl Makefile.PL
make
make orao

IRC bot which replace human memory

• web archive with search
• irc commands: last, grep/search, stat, poll/count
• tags// in normal irc messages (tagcloud, filter by tag, export as RSS feed)
• announce /me messages to Twitter (yes, lame, but that was a year ago)
• tags are available as html links for embedding (in wikis)
• RSS feed from messages with tags (also nice for embedding)
• irssi log import (useful for recovery in case of failure of machine or service :-)
• announce new messages from RSS feeds (nice for wiki changes, blog entries or commits)

• make local copy of two upstream branches using svk (loosing original order of commits, even if we are commiting into same svk mirror copy at our side)
• install post-commit hook in upstream repository which will call (over https) svk sync at our side (I would probably use SMTP to trigger that, but our machine with svn repository doesn't accept outside e-mail)
• install local post-commit hook to send e-mail notifications

#!/bin/sh
ssh -L 13690:10.1.1.1:3690 1.2.3.4 sleep 2 &
pid=$!
SVKROOT=/home/user/.svk svk sync -a
kill $pid

svk mirror svn://127.0.0.1:13690/project/carnet-foo /project/foo
svk mirror svn://127.0.0.1:13690/project/carnet-bar /project/bar

www-data ALL=(user) NOPASSWD:/home/user/svn-pull.sh

#!/bin/sh
echo -e "Content-type: text/plain\n\r\n\r"
sudo -u user /home/user/svn-pull.sh

  <Location /upstream-svn-update>                   
        Order allow,deny
        Allow from 1.2.3.4
  </Location>

svn log -v -r $REV file://$REPOS | grep ' /carnet' 2>/dev/null \
    && wget -q -O /dev/null https://svn-ours.example.com/upstream-svn-update

cd /srv/carnet-foo
# update repository to last upstream version
svn update
# delete old .svn directories
find . -name ".svn" -exec rm -Rf {} \;
# checkout new repository
cd /srv
svn co svn://svn-ours.example.com/carnet-foo carnet-foo.new
# copy new .svn files to old repository
cd carnet-foo.new
find . -wholename "*/.svn/*" | cpio -pvd ../carnet-foo/
# cleanup
cd /srv
rm -Rf carnet-foo.new
# following shouldn't return any differences
cd carnet-foo
svn diff

...učenicima se do četvrtog razreda izgubi ta žar u očima koju imaju kada prvi pita dođu u školu...

Postojao je narod koji nije imao pismo. U jednom trenutku vođe naroda odlučile su da treba uvesti pismo, pa su uvele po jednu olovku i svaku školu. Kako to nije urodilo plodom, odlučili su u svaku školu staviti po jedan razred koji je imao po jednu olovku na svakom stolu. Naravno, svi znamo da je bolji način dati svakom učeniku olovku.

rm tmp/*
pdf2swf -p 1-20 -s insertstop magazine.pdf -o tmp/pages.swf
swfcombine -o tmp/pages+nav.swf SimpleViewer.swf viewport=tmp/pages.swf
jpeg2swf loader.jpg -o tmp/loader.swf
swfcombine -o tmp/magazine.swf PreLoader.swf loader=tmp/loader.swf movie=tmp/pages+nav.swf
cd tmp && swfdump --html magazine.swf > magazine.html
cd -

$ ls -al hda
-rwxrwxrwx 1 dpavlin root 4001292288 2008-01-20 00:59 hda

Disk hda: 0 MB, 0 bytes
255 heads, 63 sectors/track, 0 cylinders, total 0 sectors
Units = sectors of 1 * 512 = 512 bytes
Disk identifier: 0x332b332a

Device Boot      Start         End      Blocks   Id  System
  hda1              63     4819499     2409718+  83  Linux
  hda2         4819500     7775459     1477980   83  Linux
  hda3         7775460     7791524        8032+   c  W95 FAT32 (LBA)
  hda4         7791525     7807589        8032+  ef  EFI (FAT-12/16/32)

sudo mount hda 1 -o loop,offset=`expr 4819500 \* 512`