PMD 85

The PMD 85 was an 8-bit personal computer produced from 1985 by the companies Tesla Piešťany and Bratislava in the former Czechoslovakia.

They were deployed en masse in schools throughout Slovakia, while the IQ 151 performed a similar role in Czech part of the country.

PMD 85s were famous for their overheating problems, and were jokingly referred to as "coffee machines".

This computer was produced locally due to a lack of foreign currency with which to buy systems from the West. After the fall of socialism in 1989, production of the PMD 85 was stopped. PMD 85 was not competitive in quality or features compared to foreign PCs available at that time.

Contents 1 Specifications 2 Variants 3 See also 4 External links

Specifications

• MHB 8080A 2.048MHz CPU
• 48 KB RAM
• 4 KB ROM
• System monitor
• Tape utilities
• TV output
• 288×256 resolution
• 4 levels of grayscale or colours, changeable in 6 pixel wide stripes
• tape recorder interface
• ROM module interface. A ROM module with the BASIC programming language was a standard part of the computer, but there were more ROM modules designed and produced, containing Pascal, LOGO and more.

Variants

• The PMD 85, first version, produced by Tesla Piešťany (author was Roman Kiss), was originally in a white-coloured case and later in some other colours. It was more of a prototype and is quite rare today.
• The PMD 85, second version, produced by Tesla Bratislava, was known as "the" PMD 85, and sometimes labeled as PMD 85-1. It was made with a dark gray case, and was famous for its keyboards with extremely tough keys. Alphanumeric keys were evaluated in the moment of a key release.
• The PMD 85-2 introduced some improvements in BASIC, some in input routines (for instance, key autorepeat), and a much more ergonomic keyboard (but much less mechanically reliable). Some of the changes caused it to be not completely backward compatible.
• The PMD 85-2A used different hardware, leading to less overheating of the memory chips, an additional 8 KB RAM and more memory for BASIC, but was otherwise compatible with PMD 85-2.
• The PMD 85-2B had 64 KB memory modules instead of 16 KB
• The PMD 85-3 added colour TV output – former versions had colour output only when used with a monitor – and some more hardware changes, including mapping all the address space into RAM, which meant it could be made almost 100% compatible with previous models by loading their ROM in appropriate memory locations. Character encoding included all Czech and Slovak characters, and a Cyrillic version was also produced.

The PMD 85-2 was an inspiration for the MAŤO personal computer, also sold as a self-assembly kit. It had different hardware and very limited compatibility with PMD; its BASIC, memory structure and I/O were almost, but not completely the same, but tape format was different. It was intended as a home computer, but never really caught on.

Later, the Didaktik Alfa and Beta were produced as more reliable clones.

See also

• MAŤO

External links

• The most modern emulator by Roman Bórik & Martin Bórik - RM-TEAM

• DJ Martin Schotek's page

• PMD-85-1 Hardware emulator with TV out