80-Bus News

  

November-December 1983, Volume 2, Issue 6











Page 56 of 67











56

of the data, so that any delays in the data will cause similar delays in the recovered clock signal, hence everything stays in step.

With the ‘Packet Radio’ concept, the data rate is comparatively slow, 1200 BAUD or thereabouts, so clock recovery could be in software, and all functions could be controlled by software and not expensive beasts like the Zilog 28530 SCC device. Of course, the data recovery is not the whole story. What about the routing and address information? Well this forms another rather nice feature of ‘Packet Radio’. The International Standards Organisation (ISO) have developed a model network structure in a truly generalised form. It’s a hierarchical thing with seven layers from the low level primitives which form the sending and receiving part through to the final high level controllers and routing protocols. All clever stuff, and I don’t understand half of it – yet!

But whereas, in the last issue, I was thinking of playing with AMTOR, perhaps I’ll change my mind and have a go at this instead. With the amateur radio regulations in the state they are, and the very woolly UK definitions regarding data transmission, it should be alright on 2 metres or 70 cms.

Nascom News

Since Lucas took over Nascom, I sometimes wonder what’s been happening. In the last two years, Nascom have got the disk system out of the door, rewritten all the manuals, brought out a Nascom 2 in a box, called the Nascom %, have produced a colour card, made their Nasdos based network work, and bought a lot of software that no-one seems to want. Although this represents a lot of consolidation of the Nascom range, in real terms, it’s not a lot. Well Lucas seem to be getting concerned about the lot of nothing which seems to be happening in Warwick. A few heads have rolled and a general shake up seems to be taking place. Work seems to have been happening, and they have a very nice (no, excellent is a better word) piece of software running under CP/M called LOTTI. LOTTI is a CAD package (CAD stands for Computer Aided Design) using the Nascom AVC to full advantage. Coupled to a multicolour chart plotter it is capable of A2 and A3 drawing of considerable complexity. The name Nascom seems to be in the decline however, it’s now Lucas Microcomputers, with Nascom being a model name within the range. There’s a new range of machines called the LX (looking suspiciously like the Quantum 2000 although with different cards fitted), two printers carrying Lucas badges, and a couple of monitors also carrying Lucas badges. The future of kit Nascoms seems a little doubtful, as the emphasis is now on built, ready to go machines.

Letters and things

A couple more letters have come my way. So lets’ have a look at them. The first from A. M. Davies of Tewkesbury encloses two programs written for RP/M or CP/M which appear elsewhere in this issue, he also raises a couple of points. Firstly the topic of DISKPEN VG:1 and GEMPEN VG:1. As most readers are aware, these are almost identical products. The confusion arises from DISKPEN VG:3, this is so much of a revision of DISKPEN VG:1 as to be considered as an entirely new product. With version VG:1, distribution was through Gemini, hence the greater number of GEMPEN’s around. With DISKPEN VG:3, distribution is through the majority of Gemini dealers, but the product originates from the authors rather than Gemini. Mr. Davies asks, why, having returned the registration form, he was not informed of the enhancements to his DISKPEN/GEMPEN VG:1 (he does not say which). Well this is difficult to answer, if he owns a DISKPEN, then he may have been, as about 50% of DISKPEN owners have been circularized with the remainder to follow in December. If he owns


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