80-Bus News

The Above System. Before continuing, I shall describe the system outlined above for those unfamiliar with the list of numbers given. It is a Gemini based system consisting of CPU/​RAM, IVC and FDC boards with one 800K Micropolis drive, Nascom I/O board, Gemini extended keyboard, CP/M, Compas 1, Gempen, Gemzap, Gemdebug and Comal-80.

The Article Suggestions.

1. The simple answer is ‘read the manuals’ where you will find details of all the files on the master disk. Certain ones (FORMAT.COM, BACKUP.COM, CONFIG.COM, READCAS.COM, WRITCAS.COM, SAVEKEYS.COM and SAVEKEYS.MAC) have been supplied by Gemini and will be found in the GM555 manual. The other files are all standard Digital Research CP/M files and are described in the Digital Research Manuals. These latter files will also be covered in many of the CP/M books available.

2. There really isn’t much that can be said here. The Nascom I/O board can have up to 3 Z80 PIOs, a CTC and a 6402/8017 UART. Presumably you had some application in mind when buying this board and without knowing this I can only suggest looking at the relevant device manuals. In addition you will find that the CONFIG program provided with your CP/M will allow you to use one of the PIOs as a parallel printer driver instead of the one on the GM813, and will allow you to use the 6402 UART in place of the 8250 on the GM813. This latter possibility is rather pointless as the 8250 has software selectable baud rates, data bits, stop bits, parity etc as well as handshake signals whereas the 6402 has to have its baud rate set by link selection, and other parameters can only be changed by ‘hacking’ the PCB. One item that you may find of interest is an article in 80-BUS News Vol. 2 Issue 1 on the ‘Interrupt System of the Z80’.

3. I am not aware of any specific list other than the one that your dealer will have of the software available from Gemini along with any other items that he gets from elsewhere. In addition you will find adverts in this rag from time to time. Finally, there are of course the computing monthlies, in which you will find all sorts of CP/M software packages. One thing here is to make sure that you purchase the software in the correct format – if this is not possible then a good bet is to choose IBM 3740 single density, single sided, 8″ format as this is just about the only ‘standard’ disk format around, and a number of Gemini dealers can offer a transfer service from this.

4. There are several COMAL books around. Two that I have heard of are ‘Structured Programming with COMAL’ by Roy Atherton, and ‘Beginning COMAL’ by Borge Christensen. Both are published by Ellis Horwood, but I have read neither so can comment no further.

5. No particular comments here other than applying some common sense. Always keep the disks in their sleeves when not in use, and preferably in some sort of container away from knockable over cups of coffee. Also avoid magnets. Do not smoke around the drive as the particles are nicely abrasive on those expensive disk heads. Use decent quality diskettes that will not shed their oxide all over the heads – if you do this then you should never need to use a head cleaning kit. Some of these kits do more harm than good and the ones that look like Black and Decker sanding disks shoud definitely be avoided!

Finally, with regard again to Mr Barrington’s comment about a spelling checker for Gempen, I hear that there is one of these planned for the new version of Pen, and it will be called SPeLLAID (lower case ‘e’ deliberate!). Let’s howp thet niether Dave Hunt or Mr Barrington hav anithyng too do with the dicshunary for thiss! I hope that these comments have been of use.