ps/2

50-line text mode on a gas-plasma screen

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I took this photo while working on the MS QuickBasic version of our benchmark (previously written in C and Assembly). The goal was to compare speed of different languages and compilers. This required me to relearn BASIC so I always needed to see online help, my BASIC code and the original C code on a single screen. Switching a screen into the VGA 80×50-character mode is invaluable in these situations.

Regarding the results: I tested all versions of our benchmark, which is mostly about integer performance and memory access (similar to compiling and XML parsing), on this IBM PS/2 P70 with a 20-MHz 386 (DX). Interpreted QuickBasic 4.5 version was used as a baseline (1x). These are the speed-ups:

  • Compiled QuickBasic = 3x
  • Borland C++ (8086 instructions) = 15x
  • Borland C++ (386 instructions) = 33x
  • Hand-tuned Assembly (386 protected mode) = 70x
  • Metaware High C/C++ (386 protected mode) = 70x

Repairing IBM PS/2 P70 before Bytefest

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I shared a photo of computers we brought to Bytefest (a vintage computer show in Czech Republic). IBM PS/2 P70 was one of those which needed fixing before the show. In this case, there were issues with an Alps floppy drive and power supply. I have to admit that this was one of the most painful disassemblies we did.

This is a dream machine for a user but total nightmare for maintenance. One example – it was necessary to disassemble a half of the unit just to connect a floppy cable back to the drive.

Bytefest 2018

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I’ve brought some of my computers to Bytefest (a big Czech vintage computer show): Apple PowerBook 100 with an external floppy drive, IBM PS/2 P70 as a cool gas-plasma-screen serial terminal, SGI O2 (used only as a hard drive cloning machine running in headless mode), SGI Octane2 with all necessary peripherals and DELL Precision M50 for sharing wireless Internet connection with my other machines (and also to show how the graphics workstation market changed in less than two years from Octane2).

Windows 3.1 on Gas-Plasma Displays

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Windows 3.1 running on IBM PS/2 P70 with the gas-plasma display. There was a special color scheme included with Windows 3.x specifically targeted for use with this type of screens (to minimize the screen burning effect).

Laptop Display Troubles

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IBM PS/2 Model P70 (1989) on the left side and Toshiba T2200SX (1991) on the right side. The IBM machine is equipped with a gas-plasma display and Toshiba has a typical side-lit passive-matrix LCD. The photo can hardly show how superior the plasma screen is. Its black is so deep that it cannot be beaten with any modern LCD. It is as fast as CRT monitors (unlike passive-matrix LCDs with 300ms response time) and as sharp as active-matrix LCDs (that were introduced a year after this machine).

There are no plasma screens in laptops today so where was the catch? It was in power consumption which was significantly higher. Typical machine with a gas-plasma display was either AC-only or with battery life usually up to one hour. Active matrix displays started to be affordable in 1992-1993 and with their color capability and lower power consumption they pushed plasma screens out of the market. Until then gas-plasma displays were the hi-end choice for many portables.

My P70 in action: https://www.youtube.com/watch?v=RaaIg8mrBkE

Kids and Old Computers

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There is a way to see many old computers running in one room in Czech Republic. It’s called Bytefest and it is probably the biggest public retrocomputing event in the country. I took about twenty computers in my car with me this year in order to show the evolution of portable computers.

There were a lot of people walking around and some of them brought their kids. It is somehow nice to see little kids trying to do something with computers that are few decades older than they are. When they grow up there is a high chance that these computers will not work anymore.