80-Bus News


July–August 1983 · Volume 2 · Issue 4

Page 40 of 55

I have used a board for some months now without being aware of any errors, and test programs I have written to exercise the RAM-DISK have run for over 48 hours continuously without finding any.

I think the parity check comes under the heading of – nice to have for peace of mind, but not essential. Statistically, the more Gemini sell, the more likely an error is to occur on one. Will you be the lucky one? (Anyone. out there won the major prize on ERNIE yet?)


The alternative way of providing a memory drive is via the normal expansion RAM boards, either the GM802 or the MAP256.

Here is a small comparison table:

Max size192k bytes960k bytes8M bytes
OperationPage-modeMAP extended page
Expansion64k units64k units512k units
Straps Solder straps to
enable page mode.
DIL switch to
select page.
Flexible, so
strapping needs
some thought.*
DIL switch
Remarks Configured system
won’t run if board
Configured system
may run if board
Configured system
will run if board
inc VAT.
* According to RB “Don’t think, you’ll only
get confused. Just follow the manual”.


The GM835 RAM-DISK is up to the usual high standard we expect from Gemini, with the usual level of documentation, and if you have applications that are disk intensive then this is the board for you. It is also close to the ideal of a ‘plug-in-and-go’ board.

It is unfortunate that the board is only available with the full 512k of RAM fitted, as the resultant £450 price tag puts it more in the court of the business user, to whom time is money. Perhaps Gemini will offer a partly populated board sometime to allow a lower cost entry to the benefits of the RAM-DISK?

Page 40 of 55