80-Bus News

  

September-October 1983, Volume 2, Issue 5











Page 46 of 67











46

of various I/O cards are available from Gemini, E V, Nascom and IO Research, whilst battery backed RAM IS available from Microcode. A full implementation TEEE488 card is available from EB V and a High Speed Arithmetic Processor is now available from Belectra. The already broad range covers most needs and the main problem appears to be finding out about the various expansion facilities on offer. Also a number of new cards will be added before the end of this year.

Network System

One of the more impressive features of the Gemini is the Network system, which can be installed retrospectively into a Galaxy. Essentially the Gemini MultiNet network system consists of a file server and up to 31 stations. The file server is based on a standard Galaxy 2 but substitutes a 5 or 10 MB Winchester drive in place of floppy in drive A. A small Network controller card is connected to the PIO on the CPU card and thence to an additional three pin connector on the back panel. Each station appears to the user as a separate disk based CP/M computer of very similar specification to the Galaxy 2 using the Winchester disk of the file server for disk access. Although the file server is normally supplied as a complete entity it is possible to up-grade an existing Galaxy into a Network file server by feeding an external Winchester sub-system (GM835) and an internal Network card (GM836UPG) and, of course, the necessary software. Gemini supply workstations for use on the Network which are similar in style to the Galaxy, but physically smaller, as they do not require an on-board disk. As with the file server the Galaxy 2 can be converted for use as a workstation with the advantage of retaining a local floppy disk capability. Gemini Dealers are able to carry out either conversions.

In use the Network is extremely reliable and the software is delightfully "bug" free. The speed is surprising; when only one station is requiring access the workstation actually responds faster than the normal Galaxy 2 due to the 250K baud network data rate and use of RAM spooling puffers on the file server. Naturally, the reponse times get longer with heavy usage. However, a 10 station Network is not markedly slower than a normal disk system. In terms of cost a Network becomes viable at about four systems, being cheaper than four separate Galaxy machines.

Conclusions

Over all the Gemini Galaxy is a complete machine from a number of angles. Complete in the respect that it can be purchased and plugged in and it will go. Complete in the respect that the machine is robust enough and with enough expansion capability to be of serious use as a development tool from both the hardware and software aspects. Complete in that would appeal to the serious business user and the computing enthusiast alike. All in all, a very capable all rounder with only a small number of niggles and at a very realistic price.

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Page 46 of 67