olpa, OSS developer

Probably there is no need to switch from CVS to subversion, but I’m starting to forget the options of the cvs command, therefore decided to migrate. Unfortunately, there is no button “convert” on the site, therefore I had to find how to do it manually.

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I need to get utf-8 (unicode) data instead of 8-bit from a Microsoft Access database (ODBC connection). It seems I’ve finally found the answer:

It’s impossible.

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To my surprise, symbolic and hard links are partially supported even by windows 2000. Here is a small summary:

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The blog is the place to remember what I always forget. Here is a note how to record a mp3 on my system.

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Picasaweb is a Google’s service for publishing web photo albums. The mainA drawback of this service is that under Linux you have to upload each image manually. The evil empire (not microsoft) knows about the problem, but has’t released even a temporary solution. Fortunately, I managed to find a workaround:
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Those who
* know what is literate programming,
* the ideas and the technical implementation behind it, and
* think this metodology doesn’t work,
can find this fragment funny (Documented LaTeX sources (.dtx files), emphasis by me):
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Many conferences create and share the list off all the participants. Before, I had a problem: I was not able to make an use of this list, and was not able to through it away (too valuable resource). And now I know what to do. I scan the list, find those who communicated with me, and create connections on linkedin. Fine. By the way, here is my profile.

After lots of trials and errors, found: to capture from webcam:

spcaview

To get a video:

mencoder -fps 6 tv:// -tv driver=v4l:width=320:height=240:\
fps=6:device=/dev/video0:hue=-40:saturation=-40:contrast=-40 \
-ovc lavc -o test.mpg

To view the result:

mplayer -fps 3 test.mpg

I still have to find how to set correct fps on input and output, and to tune brightness parameters.

After spending a lot of time to make sound working, I found how to create /dev/dsp. In my case (00:1b.0 Audio device: Intel Corporation 82801H (ICH8 Family) HD Audio Controller (rev 02)), it’s just:

modprobe snd-hda-intel

Based on experience of XML Prague 2007 and GTTSE’2007, I’ve updated conference checklist. The main addition is the section “before departure” and especially the item “switch off all the alarm clocks”.

For a few days, smtp.gmail.com has a bad SSL certificate. As result, some well-behaved mail clients and transfer agents can’t send mail to and from GMail. Quite possible, it’s the answer for a report that messages from HotMail to GMail are not delivered.

First, I was going to increment a string using this construction:

s = s + "xx...xxx"

s = "%sxx...xxx" % (s, ...)

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I’ve spent at least an hour tracking down an error in integration of my software with another software. Finally, I’ve found that Windows (ok, command.com/cmd.exe) command chdir isn’t so easy. If one wants to go to a directory on another drive, the flag /D must be used, otherwise nothing happens. Did you know it?

Just like the most of pseudo-XML tools, many RSS generators are buggy. For example, many just put the text into a CDATA section, without checking if it contains the sequence “]]>”. As result, the feed might become invalid.

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In a Scheme program, I need to distinguish infinities and NaN values. In Guile, it’s simple, it’s just the functions inf? and nan?. But when I took another implementation, I got troubles. I spent a lot of time and tried everything — =, eq?, equal?, but nothing helped. Fortunately, after a break, I found a simple universal solution.

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For long time, I’m thinking about a generative Scheme R5RS implementation. It means that if I need Scheme for a platform XXX, then I take the implementation, adapt a small bootstrap core to the platform XXX, and automatically have got the full Scheme. CPSCM seems fit to this description.

I’ve just answered on a question if it worth having a forum on a shareware site. Yes. Here is why:

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I’ve caught yet another libxml2/libxslt bug: Bug 407731.

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I need to generate S-expressions like:

(let ((val "datum")) val)

The actual expressions are more complex, the value “datum” is dynamic, therefore the special Scheme feature “quasiquote” should be used:

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One of the unit testing tools (Testeez, to be more precise) is a bit too verbose. It displays not only the failed tests, but also the passed tests. When the number of the tests is big, it’s hard to find the failed one. Therefore, I decided to highlight them in red.

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