80-Bus News


Summer 1985, Volume 4, Issue 2

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with DIAL, one for PRESTEL itself with the 14 character ID, and one without the ID for other Viewdata services. (I don’t want to give other people my sign-on and passwords.) Never mind, what’s on offer is one of the most effective and complete ‘comms’ packages I’ve seen for any machine.


Always on the lookout for something new, and browsing through the down-load section of the CBBS London West Bulletin Board, I happened across a revised version of UKM7 call UKM720. Again written by David Back, this one is two generations younger than UKM7, and is put together rather differently.

Instead of one huge source file, UKM720 has an uninitialised .COM file, and an installation program for a number of computers ranging from Gemini GM811/813 cards through Tandy TRS80 to Epson portables. The source file of the installation data file is also provided so you can add routines for any that aren’t in the list, and of course the GM870 is too new for the list. Actually, there’s a small problem here, the install program offers only 10 options, one of which is Gemini. If you want to install something else, then you must delete one from the installation data source and substitute the new. I didn’t want to do this, as everything there was useful to someone, and anyway, it looks greedy to have two Gemini options. I opted to make the two Gemini options conditional, enclosed in an ‘IF – ELSE’ assembler directive, and you reassemble for either option. The modified source for the GM870 bit is published here, but remember, if you do down load this from CBBSLW, then the source will also require an equate somewhere to indicate which MODEM source to assemble. Sorry about the 8080 mnemonics, I did shove the thing through TRANSLAT to convert it to Z80, but it wouldn’t assemble, so rather than spend half an evening mucking about to find out why, I simply added my bit in 8080 mnemonics.

This proves the advantage of having the sources in the GM870 manual, as it was a straight copy job to include it. The bit tests are done differently to the manual, but there were 10 other examples in the source showing how to do it, so no problems.

Since then I’ve had trouble with a couple of the more local bulletin boards which are supposed to auto select 1200/75 or 300 baud, they just don’t seem to work. My first suspicion was the software, but that was exonerated by trying different software, which pointed to the MODEM card, but as similar results happen with a WS2000 MODEM, I guess the bulletin boards are at fault. DISTEL does say (at 300 baud) that the auto select is experimental, so there you go! [Ed. — I have used the Gemini GM870 MODEM on an ‘auto-select’ bulletin board, and am pleased to say that it worked at either rate. Unfortunately I can’t remember which board!]

Enough for this session about MODEMs, they’re fun but tough on the pocket. Unlike yacking on the phone, you don’t tend to be aware that the minutes are ticking away. Now there’s another idea, reprogram the Gemini SVC/IVC to tick away in money rather than minutes at the top of the screen, it could pick up the charges for the phone call from DIAL. That would show just how bad on the pocket it really is.

Another New Goodie — Gemini BIOS V3.2

Another new goodie has appeared from Gemini, and not too tough on the wallet, all things considered. BIOS 3.2. Those who remember SYS will remember one of its features was the ability to run with a selection of drives. You know, Gemini DDDS on drive A and RML on drive B. Or, substituting Teac TD55-F (double sided 80 track) for the standard Gemini arrangement of the time of Micropolis 1015-V (single sided 80 track) drives. A lot of SYS’es saw use for just this purpose, limited though the feature was. BIOS 3.2, which is only eighteen months late, supercedes and exceeds SYS for this purpose.

Over a period of time, Gemini have gone through four disk formats, GEMSDSS, GEMDDDS, GEMQDSS and GEMQDDS; at the same time less significant features of the BIOSes has been improved, changed, added or just done away with. One such improvement is again associated with drives. Early Gemini BIOSes know nothing about RAM-disks, later versions you hand patch to turn them on, and the latest finds out for itself what’s there and turns it on for you. Likewise, if you upgrade your drives, to a different format, the BIOS has to be changed to suit. Gemini would always do this for you, but the number of permutations is getting out of hand. All arguments for a different way of doing things, hence BIOS 3.2.

BIOS 3.2 consists of a full feature BIOS, (one or more of several versions being supplied depending on your current CP/M or system, one called BIOSF.SYS (for the floppy drive only version), a BIOSFW.SYS (for a floppy as the boot drive plus Winchester drivers, BIOSW.SYS (for the winnie and floppy version), and BIOSN.SYS for MultiNet systems), a system configuration file, a serialized CP/M core with the Gemini version of CCPZ, and a CP/M constructor called GENSYS. The system

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