80-Bus News |
July–August 1983 · Volume 2 · Issue 4 |
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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:
| GM802 | MAP256 | GM833 | |
|---|---|---|---|
| Max size | 192k bytes | 960k bytes | 8M bytes |
| Operation | Page-mode | MAP extended page mode | RAM-DISK |
| Size/slot | 64k | 256k | 512k |
| Expansion | 64k units | 64k units | 512k 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 removed. |
Configured system may run if board removed. |
Configured system will run if board removed. |
| Cost/64k inc VAT. | £144 | £82 | £65 |
| * 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?
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