80-Bus News

The choice between these three depends on your budget. You might perhaps be more inclined, as I was, toward the Gemini system as part of the whole “Multiboard” idea. I thought long and hard about these options. I also talked the whole thing over with fellow Nascom II owner. We agreed on the advantages of disks, but a definite problem emerged: Having disks opens the door to another operating system from NAS-SYS, namely CP/M. CP/M, if you didn’t know, stands for Control Program for Microcomputers. You cannot go far in computing without hearing about CP/M sooner ar later. It has many followers, particularly in America. It was written 7 years ago and there is anenormous ‘user base’ and a very efficient User Group, even in the UK. I don’t propose to go into great depths about it here but briefly it does all of the huge amount of ‘house keeping’ for you. True that NAS-DOS, DCS-DOS and POLYDOS also do the housekeeping equally as well. With D-DOS, you’d have to resort to pen and paper to record what is on your disk, and more to the point, where to find it! In my case, the final arbiter was the huge software base for CP/M.

CP/M is a good program, but it’s not NAS-SYS. We all love NAS-SYS because of its simplicity, ease of use and modification, and screen editing. Can you give that up? I didn’t want to. However, if one contemplates spending a good deal of money on a disk system, one wants to get the best out of it. CP/M has a good deal of free software in its user libraries as well as an exciting range of commercial software. Most of this expects to display output on a standard 24 x 80 VDU. Of course the Nascom display is only 16 x 48. This, in my opinion, was not on, so I considered the Gemini Video Board which gives 25 x 80. The decision to use this solved some of the operating system dilemma. There seems little point in hanging on to NAS-SYS with the video board, as they are not compatible. So I made the break to CP/M.

My choice was between the single density Henelec system and the double density Gemini as the Nascom one still hadn’t appeared at the time I actually had the money in my pocket. Had the Nascom system been around the choice would have been even more agonising. I reasoned that I would save over 100.00 if I bought the bare drives and boards and built the power supply and mountings myself. Over a week of solid full time work (in my holidays) nearly disabused me of this idea, but it worked, well almost. When built, my Nascom II, now sporting an additional 64K RAM, the Gemini IVC and FDC cards and two Pertec drives, refused to work. A good deal of time was wasted looking for non-existent faults before I finally gave up and called the supplier of the bits, Henry’s Radio. This is where I had a surprise. I imagined I was in for an arrogant rebuff; after all, I had not bought the recommended packaged system but had bought the bits and these had all been tested before sale. To my relief, they were very sympathetic. “Bring it in” they said. So I did, and they spent the best part of an entire day on it. They fixed it and it wasn’t even my fault! There was a track fault on the Nascom II under the solder resist. It hadn’t shown up before because it affected a signal (NASIO) that I had never used before. I was a happy fellow that day.

Readers of Computing Today may have read of one man’s dissatisfaction of CP/M. Much of what he says is fair comment – it isn’t easy to give up one operating environment for another, and I also mourn the loss of Debug. However, all is not lost; screen editing for example, is still possible under Gemini’s implementation of CP/M, thanks to a few familiar names like Richard Beal and Mr Parkinson.

No mention of the CP/M system is complete without a reference to its extensive software library. As there are something like 300,000 users of the system, much software has been written over the years. There is a large club in the US and they have collected a library of 51 8″ diskettes (I’d guess about ten megabytes worth!) of programs. Inevitably, not all of them appear useful. Some of the early programs have been superceded by improvements on later disks and thus there is some repetition. There are games and music programs as well as many utilities and languages. There is also a “Special Interest Group” (SIG) in the US with a wealth of interesting programs. Any of these disks are available through the UK CP/M Users Group, providing you are a