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Re-making a gear for tape memory

2017-09-24 01:47:52,  In: DIY, Electronics

A long time ago I acquired a microcomputer-grade tape recorder produced by Polish factory: MK-450. The problem with this device and a few other tape drives (like Mera one for large cassettes) and even consumer-grade decks (MK-250) was a poor quality of its gears prone to breakage. Usually, during seeking or playback, a loud crack is heard and tape is pulled into recorder or forward seeking stops working while motor is still heard. Recently I got a possibility to print something with 3D printer, so I decided to experiment with it. In this post I'll show how to re-produce the existing, physical gear into computer model. To quickly show things, the result is nice:

   But... why does it fail?

The plastic used to make these two specific gears (in MK450) is different than polymer used in other gears. It degrades into white, crumbling powder with atmospheric contact and probably...

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Installing adNauseam on PaleMoon and the new malware problem

2017-09-02 13:30:12,  In: Hack, Other

Recently PaleMoon developer decided to blacklist adNauseam extension, so here is a quick method of re-enabling it:
1. Go to about:config
2. Set extensions.blocklist.level to 3.
3. Install addon, go to Tools -> Extensions and turn it on there. Remember that it takes the function of adblocker so will collide with most Adblocks.
4. Watch your addons as this may allow to install uncertain ones in the future (currently only adNauseam has this level). If you want to know, the list is online-updated and is maintained in blocklist.xml in your profile directory. Configuring adNauseam, if your workflow involves visiting only a set of trusted sites you should turn on exception for non-tracking ads.
And small explanation what is it.
The add-on fights with unfair malware-delivering companies (today re-defined as "advertisement") by hitting their collaborators - website authors. Then, according to ideology called "free market", authors should change malware...

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Curiosities: Inside a lab-grade power supply from 1970s

2017-08-22 01:17:11,  In: Electronics, Curiosities

Some time ago I was looking for an used adjustable power supply unit. Finally I had a possibility to purchase a 300W adjustable (0.1-30V, 10A max) power supply unit for a relatively lower price. The only thing about it was that it was a unit from early 1970s, transformer-based, 25kg of hardware. I finally got it, brought home and decided to restore it.

It is a ZTR-1/71 power suply unit made by Inco in Poland. In 70s and 80s, Inco (Full name: Zaklad Produkcyjny Aparatury Elektronicznej INCO) was known manufacturer of measurement devices, lab equipment and all "special" production e.g. for military, intelligence or security offices (also devices for communication, location of radio stations or radar applications), so I expected quite interesting things inside. It is still possible to get their old catalog on Silesian...

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Memory usage of different desktops in Linux (UPDATE: 32-bit)

2017-08-02 14:02:11,  In: Linux, Debian

While installing Linux on older machines a very popular question is "What desktop environment should I use?". With older machines, usually the biggest bottleneck is not a CPU, but RAM. Too small memory causes swapping, and it slows Linux even more. On the other hand, more free RAM makes system run faster. I decided to install Debian 9 (Jessie) in different configurations to measure memory usage of different desktop environments. All measures have been made on stock installation offered by Debian installer, by installing on virtual machine.

   Linux and memory

There is a large difference between memory reported by "free" and "htop" programs. It is coming from the method of using memory in Linux. The main rule here is that unused memory is wasted memory, so Linux uses free memory for buffers and caches, making system faster. While "free" shows buffers and caches memory as used, htop doesn't, only shows buffers on memory usage bar in blue/green color, while number indicator shows amount of RAM actually...

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Eee PC 900 as ultra-portable computer

2017-05-03 17:38:06,  In: Linux, Debian, Retrocomputing

Few weeks ago I bought a damaged Asus Eee PC, model with widescreen and Celeron processor. These computers were sold about 10 years ago as "netbooks", which were a transition between notebooks and tablets, when companies were not so sure that they will force users only to consume ad-filled "content" from the Internet. The computer has been repaired and now it works. I decided to make some use of it. Let's look what is inside:
- Intel Celeron processor at 900MHz
- 1GB of RAM in DDR2 SODIMM stick
- 4GB on-board SSD disk
- 16GB SSD disk using proprietary connector.
- Wi-fi, sound, Intel GMA950 video card, SD card reader and battery - all which modern laptop should have.



Previously, the computer had Windows XP installed, in its Home edition. There is a sticker for it so someone bought a license. Unfortunately, even fresh install of Windows XP on this machine works terribly, it is slow, overuses hard disk and suffers of few-second freezes. I decided to go with Linux as these...

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LibreOffice base: One macro to open them all

2017-04-22 15:39:42,  In: Hack, Database

Recently I was developing a simple database application in LibreOffice Base version 4.x. This is quite slow tool, but with a few modifications and tricks complex applications can be made.
Usually, database application consists of several forms supporting several tables opened from each other or common "switchboard" form. The problem in LibreOffice base is that it is not possible to easily make the "switchboard" form with buttons launching forms for other tables. There is no "macro wizard" to make it easily and most existing databases use extensions or hard-coded macros for it.
Officially, the only way to do it is by using Switchboard extension which is not much supported in later versions. Another way is to create macros for buttons. If you have 10 buttons opening 10 forms, you will have to make 10 macros connected to them, opening different forms. As in pure Open-Source programs, the only documentation is source code. Let's do it in more universal way: I inserted a target form name in ToolTip...

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Weak passwords and weak resources

2017-03-14 20:04:31,  In: Security, Other

In the last few years, questions about password complexity emerged from time to time. There are list of common passwords, they are counted in leaked daabases, in hashed and unhashed forms. Blog entries are usually alarming about the poor complexity and length of passwords. Recently, a Password rules are bullshit post on Coding Horror blog shows how password rules are bad idea. However, they seem to be insecure in totally ignored mechanism having nothing to do with their length.

To illustrate this problem, let me tell a story about graphics card drivers. In 1997, to download a new driver to my video card, I could do the following thing:
1. Go to my card manufacturer's website
2. Click Support, then Downloads
3. Connect to FTP in "pub/drivers" directory, or select board from the list
4. Download driver for my OS. Mission accomplished, driver in my disk.

20 years later:
1. Go to my...

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A hole in the casing

2017-01-30 20:50:00,  In: DIY, Retrocomputing

Sometimes old computers come with broken plastic parts. When only cracks are present, it's easy - we can fix them with glue or staples melted into plastic using soldering iron. Even totally broken casing can be fixed this way. The bigger problem is when the casing lacks some part which cracked off. Recently I purchased an old computer with broken front panel. From photos it can be seen that damages aren't so big and two parts can be glued together, but if you look closer you will notice that a whole bottom-left corner of panel is missing. How to fix it?


I decided to try with hot-melt glue applied from pistol-type hot glue applicator. First, I found that front panel is made of porous, well-glueable plastic, so I glued broken parts together using cyanoacrylic glue. I found that this panel is painted with something similar to white acrylic paint. Next, I started to apply hot-melt glue to form a patch. The key factor here is temperature. The glue comes from the gun very hot. When hot, the glue is liquid...

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Windows 98 - fixing file operation delays

2016-12-24 04:12:59,  In: Hack, Retrocomputing, Windows

Another text from series "Notes to myself". After installation of Internet Explorer 6 in Windows 98, some weird things may start to happen. It starts when large amount of files are deleted, moved or copied. After this operation every refreshing of explorer window related to renaming, moving, copying or deleting causes a minute hang of Explorer window. This persists until restart.
This is caused by a bug in Internet Explorer 6 shell, which is totally harmless in NT-based Windows systems, while in Win9x causes hang. And although MS has been notified about this problem since 2002, they haven't released any patch. The only thing we can do is to replace the part IE introduced to Explorer using the one from previous version, version 5.5.
But we have a IE 6.0! We need to use separate DLLs for IE and Explorer shell. So let's begin:
1. Obtain Internet Explorer 5.5 in Your language, CABs version, not a downloader which doesn't work. Using WinRAR, WinZIP or any other archiver supporting CABs, extract...

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Building Ted under Debian Jessie

2016-11-25 21:30:22,  In: Linux, Debian

Ted is a Linux rich text editor which has one significant good side: It is not bloated. It is written in pure C/C++ and offers everything a simple word processor may offer: Pages and margins, choosing font, attributes (bold, italic etc.), saving to text files, RTF and even simple HTML format. But the most important thing in TED is that it is not wasting memory and CPU cycles for useless things. Editors which need GTK require few GB of libraries. AbiWord likes to pull significant part of Gnome from repo. Ted is just working on basic libraries. It is possible to have a program to write being focused on writing without gigabytes of libraries! However, the biggest problem with Ted is that it is not supported anymore in Debian, as well as in many other distributions.

Unfortunately Linux is a system for programmers, and programmers like to write code. WYSIWYG software has no chance here to be maintained. So Ted became difficult to build. In this text I'll show how to build Ted in modern Debian Jessie...

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