80-Bus News


July–August 1984 · Volume 3 · Issue 4

Page 20 of 43


The 172 – 178K Ramdisk capacity now available from the GM862 is just about large enough for ‘serious’ applications requiring lots of data transfer, where its fast and silent operation is a definite asset. Also, using the Ramdisk as the working drive, having first loaded the appropriate software, helps prevent real disks becoming cluttered with all sorts of rubbish in less important applications. The single GM802 Ramdisk with its limited 52 – 58K capacity may not be of so much ‘real’ use, but is quite a good educational toy, enabling techniques to be developed and casual remarks about having 128K of memory aboard to be dropped to flatten Scrotum and Beeblbox braggarts. I intend, sometime, to arrange for SIMON to be switched out of the memory map on completion of the CP/M boot so as to enable entire 64K, rather than 60K, pages to be selected. However memory space will still be occupied by the Ramdisk directory and ‘common area’ needed by Page Mode so the actual gain in capacity will be modest.

The Final Word

Although the Gemini GM862 is relatively expensive compared say with some 96 t.p.i. disk drives, it is attractive to Galaxy and Multiboard users, who can fully exploit its more advanced features. Nascom users looking to upgrade in the future, but who need Ramdisk now, should also consider this board. Used GM802 boards, sometimes available at about half their original price, offer a way for the amateur to get into Ramdisk (and go on the Rampage).

A Review of the Microcode BP14C Backplane

by D. G. Richards

Way, way back in May of ’84, my faithful old Nascom-1 crashed (again). At the time I was using a database program which was up-dating a very large data file; needless to say, all data was lost forever. Now it’s things like this that get me real peeved, so after doing the rounds of all the local sources of electrical interference, e.g. the fridge, CB rigs, etc, I went next door and gave their cat a good kicking, just to be on the safe side (thanks for the warning about cats, Dr Dark!).

When all the above proved fruitless, I decided it was time to take a close look at my Nascom, you know the old saying, “When you’ve eliminated everything you can think of, whatever’s left is probably to blame.” The only thing left that I hadn’t checked was my computer. Was my Nascom at fault (shock, horror, probe)?

The answer to the above was – NO. My Nascom checked out OK, as did the ether boards in the system, except for the motherboard. Now, my motherboard is of the Vero-board type (when I started expanding my system back in ’81, this board was considered hi-tech) and over the years I’d done some really horrible things to it, like adding 1,000 uF capacitors to the power rails, and soldering 16 SWG copper wire onto the power rails in an attempt to make my fast failing 3 Amp PSU last just a little while longer.

The result of all this soldering on my motherboard was that instead of it being flat, it was more banana shaped, and, infact, it was a real ‘mother’. The time had come to put my dear old motherboard out to grass (no, no, I said “out to grass” not “onto grass”, twit).

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