17 декабря 2015

                 ZX Spectrum in Czechoslovakia
                          by Ellvis

At the beginning of 80's people started to bring first ZX80 and
ZX81 computers from abroad. It wasn't anyhow easy and it was 
pretty rare, because it was not easy to travel to the west, it
was expensive plus the payments on the borders (that was
advantage of firstSinclair's computers, they've been small so
easier to bring without border police to notice:). It wasn't
really possible to buy a computer in Czechoslovakia at that
time, they've been sold just to schools and companies (and
produced in very small series).

In the middle of the 80's there was already huge community of
8bit computers users. It was possible to buy them in"Tuzex" -
those were special shops where you had to use something like
coupons instead of money, they were expensive. People were
bringing more and more computers from abroad (mainly
ZX Spectrum, but also Atari, C64, Sharp and others). Some 
computers started to be produced also in Czechoslovakia - PMD85
and IQ151 ( 8080 based), SAPI ( Z80 based) and so on. But they
were usually impossible to buy for home use (and expensive).

Small companyDidaktik (they produced educational stuff for
schools as rulers, tables and so on) started to produce
computers. At first, it was Didaktik Alfa and Beta, which were
intended for schools (they were compatible with PMD85, so 8080
based).

In 1987 they started to produce Didaktik Gama - ZX Spectrum
clone. It had original Sinclair ULA, U880D ( Z80 clone from
eastern Germany) and was in fact a modified Issue 3 of
ZX Spectrum. It had fixed some ROM bugs, added centronics 
drivers for printers, 8OkB of RAM (2 banks of 32kB) and i8255 as
a parallel interface. First version was quite buggy (it was
marked always by the year of production, so it was Didaktik Gama
'87, '88, '89 had different charset and finally '90 ) but they 
improved and it is pretty good computer even today. It is 99,99%
compatible with ZX Spectrum including perfect timing (port 127
is used for switching the memory) and pretty reliable.

Didaktik Gama ended in 1990 and Didaktik M was the follower. It 
had just 48kB of memory and used PLA (or ULA1 ) instead of
original ULA /maybe that was a kind of TЗЧVG1 from USSR - Ed./.
Compatibility was worse - the timing is different (no contended
memory), but it had nice case and quite good keyboard. The PCB
is of bad quality. Production of those ended in 1993.

The last computer fromDidaktik was Didaktik Kompakt, that one
was Didaktik M with disk drive (D80) in one case. Everything
ended in 1994 (I think).

Except computers,Didaktik was producing also some peripherals.
One of the first was Didaktik Melodik, it was AY interface for
48k Spectrums (including Didaktiks). It had small reproductor
and 3,Smm jack as output (in ACB stereo).

Next interface was Didaktik M/P, which was parallel interface
for ZX Spectrum and Didaktik M (it contained i8255 and ROM with
printer drivers so it was not working with Didaktik Gama ).

The very famous was Didaktik 40 and Didaktik 80. Those were
diskette drives with own operating system (1ЧkB ROM and 2kB
RAM). It was most used disk system in Czechoslovakia. Didaktik
40 used 5,25" diskettes formatted to 3бOkB (DS/DD) and Didaktik 
80 used 3,5" diskettes. Operating system was calledMDOS 
(developed out ofSINDOS ), it was possible to connect 2 disk
drives and all 2 versions existed. /Later version 3 appeared./
It was based on WD2797 (later replaced by another version
causing some compatibility problems) and contained also i8255
as a parallel interface.

Lot of various interfaces for ZX Spectrum were produced around
the whole Czechoslovakia including disk drive "Dataputer Quick".
This one was interesting by emulation of D40/D80 system, but it
used also it's own native system.
/There were also a couple of schemes for CP/M support: LEC 
Memory Extension (1987) and Sinsoft's scheme (late 80's), but 
his mentionedSINDOSwas not CP/M compatible: 
http://retrocip.cz/uplne-alternativni-spectrum/ /

At the beginning of 1989, home made clone Mistrum was published
in a popular electronic magazine. It was pretty complicated and
had different timing, but it was something possible to build at
home. It was clone of Spectrum 48k.

Economic situation was a bit different then in USSR. It was even
possible to buy "valyuta", but with some complications and not
in big amounts. As I wrote already, there was a network of
"Tuzex" shops that were selling stuff from abroad for a coupons
called "Bony". It was very expensive.

As for electronic parts, they've been normally sold to people in
electronic shops. But often some of them were hard to get
(oscillators, some integrated circuits and so on).

All this ended in 1990 were Czechoslovakia transformed into
capitalistic country.

An article about this is here:
http://hackaday.com/2014/12/15/
home-computers-behind-the-iron-curtain/
but I don't agree with it for 100%.

                             * * *

WhatFactorб wrote:

According former Czechoslovakia, the most common setup in the
80s was a 48K Speccy with a tape recorder and maybe a joystick
interface (and a living-room telly or a small b/w telly). No
128Ks, no AYs, no disk drives. After fall of communism borders
opened and 128K Spectrums appeared, but in very tiny amount. As
well as other computers, so many people (these with money)
skipped 128K and went to Amiga/ST/PC. Didaktik was making their
very humble Speccy 48 clones since 1987. Then, in about 1991
they introduced a disk drive D40 (incompatible with 128K
Spectrums as showed up later) and Melodik - an AY ACB stereo
interface. So noone including me even knew about 128K and AY
till early 1990s. There were lucky ones like Fuxoft or Busy that
they got a 128K earlier in the 80's, but it was kinda exception.

I understand that Speccy was considered as a low-end but here it
was different in the 80s. There wasn't any chance to import
computers legally so everything was black market (until Didaktik
and their low quality ZX clones). The Spectrum was a name and
its ownership guaranteed a feed of software (in 99% pirated).
Who had a different machine, was an outsider, including C64 -
there were too few C64 people around here. There was wide Atari
XL/XE user base, much bigger than C64.

http://www.pouet.net/topic.php?post=506396





    

    

            
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