Savel brain dump in English!

There is special term- memory leak. What it is? Looks similar to brain leak, or that old joke from old zombie movie: brains brains…!

In real world, the bug in memory management is described as memory leak. Every program use some memory (RAM, Video RAM, virtual RAM) to store some data. In modern operating system, program must request from OS for some memory. After using it, the program must release the memory. But there are bugs in software, and sometimes requested memory is a bit more than released. There is not a big problem, if the program is working for a short time- after the termination of process, all allocated memory is released (unless the OS have memory leak itself). But some software is running all the time computer is on. Especially in servers, where uptime is calculated in days, months and even years.

So, one buggy piece of software is Bittorrent client. Here is the result after running it for some days…

This image is more informative… 1.3Gbytes (!) of RAM is quite many for background file transfer.

I was forced to build some VPN (virtual private network)… I examined all my available documentation, did all RTFM and consulted with some gurus from local unix newsgroup.

I selected first available VPN type: PPTP. I am using Linux Debian stable on local servers. As server is running for a long time, the system was “old” stable version. So simple command “apt-get install pptd” didn’t work. There were lots of problems and missing components. So I selected other method- in some trash I picked up old Fujitsu Siemens computer. It very small, pizza box size computer with Pentium III cpu with integrated video, lan, sound and etc. I added two additional realtek ethernet boards to make “router” look cooler. If everything will be working fine, I’ll transfer stuff to real server.

Here are just illustration: screenshots of WindowsXP VPN configuration screens.

I downloaded and installed latest stable Debian. It was “etch”. All devices were installed without any problem. I installed only “base system” as I like to install all needed stuff by myself.

apt-get install mc iptraf lynx ssh

I like these programs, so I installed them. Especially “mc” as I love old style, norton-alike file manager.
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From time to time I repair computer. Sometimes it is just software problems, sometimes- hardware. But some times it is dust problems. Dust full computer appears on my workbench very often, but I don’t have my digital camera nearby to take a picture. Sometimes I open computer cases at client’s home and I don’t want to take pictures…

But here is few pictures of real computer I repaired and short description of the problem:

This computer “was running quite fine, only few sudden reboots in a day”. But when weather temperature raised because it is summer now, computer’s reboot become irritating and owner brought it to me.

This video card was working fine. No reboots or freezes. But how much dust it need to collect to stall GPU fan?

This Athlon sometimes freezes the computer. Especially when encoding video. Do you know why?

This video card (Radeon X800) was big secret for owner. He can’t start video games. Few months ago all games were working fine, but after some time he could not start any game. In “2D” mode, you can use computer for weeks! We tried newest video card drivers, chipset patches, even reinstalled windows few times… I only removed dust clog and everything is working.

I was browsing in Internet for some information about LCD programming. It was regular web page about some bugs in LCD software. Suddenly I noticed that my CPU fan is running very fast, case rear fan started too I and can feel hot air passing from my computer. I tested CPU load and noticed full load from internet explorer! As my system is with dual core, the whole load was only 50%, but it is too high for simple web page with three (!) animated gifs. Here is the URL to this strange web page:http://www.lcdstudio.com/forum/viewtopic.php?t=10684

I have special utility to read date from my APC UPS. According to it (see the screen shots), my computer consumes about 267W of energy when showing simple animated gifs. On the right side image there is snapshot of “idle” computer- only Outlook express, Photoshop and other background stuff. So Microsoft is using up to 76W just for displaying some animated gif! BTW, firefox didn’t use any extra watt for this web page- the CPU load is zero.

(Two images on one place.)

Here is screen shot of idle computer (google webpage display):

And here is mystical load when looking to animated gifs. I have dual core, so one core is idle. I tested this page at my workplace and single core computers were loaded to 100%.

Maybe Bill will fix it? I have some reports that new Vista windows have same bug. If you want to test this page, please set that this web page is displayed with all images visible, IE windows active. Please wait for a while to get full result- CPU load grows after some time.

I disassembled few batteries from notebook computers. There we some “economical” versions among them. Such “lite” versions are typical for “sales” version of computers- when the price is in matter. In notebook datasheet all working times are for normal batteries and with “no load” situations. When you buy computer on “sales” event, you’ll receive “light” version of batteries. Here is few photos of open “lite” versions of batteries with small description.

Here is the 14.8V, 2000mAh version. Normal version in same box is 14.8V, 4000mAh. The capacity is halved. 30Wh versus 60Wh.

Here another version of lite cells. Our days the notebook computer’s hardware can work from “any” voltage. Switching power supply can drain power from any type of source. So, here is another version of lite batteries. User may learn to calculate capacity in mAh, but energy is stored in Wh. So we can leave SAME capacity, but reduce voltage a bit. In the top: 11.1V, 4000mAh battery. This means only 44Wh versus normal 60Wh.

Lower one is typical low capacity version with reduced Lion cells. Here is only some mystical high precision capacity 2000 v.s. 2150. The 7.5% means many when counting length of … but when it is capacity, this means nothing. They use special plastic tube spacers to reduce Li-ion cell wobbling in battery.

Both batteries have identical bodies. The marking on the battery is good. The manufacturer didn’t lie here.