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D > DIDAKTIK > Gama   


This was a Slovak Spectrum clone made by Didaktik Skalica Ltd. in communism times (1987). It offered 80 KB RAM.

As all Z80A based computers, it was not possible to address more than 64k. So the Gama computers used a bank switching technique, with two 32k additional RAMs. There was even a LED on the case, which indicated if the RAM have been switched or not!

The Gama computers had a built-in paralel i8255 interface. They used the original Ferranti ULA and had russian made memory chips.

The Gama computers were not fully compatible with the original Sinclair Spectrum due to some system variables differences.

In fact several models were made.

- The first one was black and, as it was made in 1987, it is often called Gama'87. It had a bank switching bug : if you switched the banks and the RAMTOP variable was above 32768, then the computer simply crashed...

- In 1988, the Gama'88 was launched (grey case). It's main difference is that the bank switching bug was repaired.

- One year later, the Gama'89 (guess why) was released because the '88 model was still quite buggy. Some bugs in ROM were corrected and hardware was a little bit changed, so the compatibility was improved. It has only latin character set and a print routine was implemented in ROM. The Gama'99 was the last and the best model of the Gama serie, it was manufactured up to 1992.


Branislav Bekes sent us info and specs for the Gama'89 :
CPU Z80A, ROM 16k, RAM 80k bankswitched, graphic mode 256x192 with 8 colors, text mode 32x24. Two bottom lines were reserved for interpreter. Sound 1bit beeper.
I/O ports : TV OUT, VIDEO OUT, TAPE IN/OUT shared with POWER SUPPLY connector. Expansion slot and 8255 interface. Power supply is external and offers +5V and +12V.

About the Ram switching, Abraham add:
The memory banks switching in GAMA was used for "tricks", like enabling on GAMA the AY sounds and music in games designed originally for ZX 128, taking game screenshots, enhancing the copy programs and many more things.

NAME  Gama
TYPE  Home Computer
ORIGIN  Slovakia
YEAR  1987
BUILT IN LANGUAGE  Spectrum BASIC interpreter
KEYBOARD  Full-stroke keyboard, Sinclair style, 40 keys, reset button
SPEED  Unknown
RAM  80 KB (16 KB + 2 x 32 KB)
ROM  16 KB
TEXT MODES  32 columns x 24 lines
GRAPHIC MODES  256 x 192 dots
SOUND  Beeper (1 voice, 5 octaves)
SIZE / WEIGHT  27 (W) x 16.5 (D) x 3.6 (H) cm
I/O PORTS  i8255 interface, expansion bus, TV and monitor output, tape-recorder sockets
PRICE   6000,- Kcs (Kès) (1987, Czechoslovakia)

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