80-Bus News


November–December 1983 · Volume 2 · Issue 6

Page 65 of 67

Random Rumours (& Truths?)

By S. Monger

This is where they are.

In my last bit, in Vol. 2 Iss. 3, I asked the whereabouts of several products that had been announced, but at that time had not actually materialised. We are now six months further on, and so what is the current position? Well, the Sinclair Microdrive has appeared and is NOT a disk, but a continuous loop tape – consequently the person that I’d mentioned who intended to try to interface one to his 80-BUS machine has long since abandoned the idea. I believe that Lucas now have Winchesters available, and understand that if you open them up (the units, not the Winchesters !) and look inside you’ll find a Gemini GM829 FDC/​SASI board! The Gemini GM818 serial board has now materialised, but beware! The GM818 is now a daughter board for the GM816 I/O board, and contains two 8250 type UARTs – the originally announced synchronous board has been redesignated the GM848 and is still some weeks away from availability. IO Research’s Palletteis now available, for those that can afford it, and for those that can’t the Mini Pallette is a meagre £300ish ‘cheap’ lower spec alternative. Still no sign of IO-Net.

Other New Products.

One item that was sneaked out without my prior knowledge was the Belectra Arithmetic Co-Processor board, but this was covered in some depth in the last issue by David Parkinson. Another co-processor board has also been announced, but no delivery date has yet been given. The Gemini GM886 will contain an iAPX186 (otherwise known as 80186 – i.e. a super GT 8088/8086) and a ‘large’ amount of RAM (256K?) as well as a socket for the 8087 (ultra high speed, ultra high price number cruncher). As already mentioned, the board will be added to an 80-BUS system as a co-processor board. i.e. the existing Z80 system will continue to handle all keyboard, screen, printer and disk requirements, whilst the 186 will be capable of running CP/M86, Concurrent CP/M and MS-DOS (Gemini are vague as to which they will be making available).

Much more imminently available is the Gemini GM832 SVC (Super Video Controller) board. This is a considerably enhanced GM812 IVC. For a start the 4MHz Z80A has been replaced with a 6MHz Z80B, and consequently, along with the effects of a number of other hardware and software changes, the board is much faster. The programmable character set has been extended to all 256 displayable characters and so the board becomes much more suitable for supporting foreign languages (as well as being more flexible for ‘Space Invader’ type applications!). Character attributes are also available – half-intensity, blinking and inverse characters, and half-tone backgrounds, plus combinations of these (although different attributes cannot be used on different character cells at the same time). A buzzer is also fitted. But to many the most interesting addition will be the graphics mode, providing a 256x256 bit-mapped display, with graphics primitives of line and circle drawing, polygon fill etc being included in the on-board monitor program. It is here that the Z80B comes into its own, and the plotting speed is very impressive. Estimated price is £195 (+VAT), with availability from 2Q84.

And Finally.

Mention has been made in the last couple of these rags of alleged infringement of copyright of Gemini’s CP/M BIOS. Partially because of this, and partially because of Gemini’s policy of constantly adding further facilities to their BIOS anyway, I understand that BIOS Version 3.0 is almost upon us, and that this will provide some ‘interesting’ facilities. More importantly (for existing customers), it will be made available as an upgrade at a ‘very reasonable’ price. Watch this page for further details.

Page 65 of 67