Micro­power

Now you HAVE to get down to reading the manual (several times) and it is as well to make a copy of the master disc, just in case of accidents!

First, you have to FORMAT an empty disc. This quite simple, Enter “FORMAT”, hit enter and follow the instructions as they are displayed. Put the master disc back, enter “BACKUP”, hit Enter and again follow the instructions. I then started entering my machine code files. They went in fine. The speed with which they come out is amazing. “Space Invaders” loads in about 2 seconds flat.

However, now my troubles starts, PolyDos supports a very useful disc basic system but when I tried to use it by entering “BASIC”, I got a series of “error”s flashing and nothing else. So, once again to the dealer who now said that I needed 48K of RAM and not the 32 which I had. Nothing for it but to shell out for a new RAM board with 8 new 4116s and add the 16 4116s I already had. (One 32k RAM board going begging but without the 4116s – however, I might incorporate it later)

Well, at last with the new RAM board installed (I didn’t even do the memory test) it all worked. PolyDos Disc Basic came up with “38851 bytes free”. My BASIC programs could now be entered and run. Much more important for me were the commands to set up Sequential and Random files, but here the manual failed me somewhat

For a Random Access File, it gives an example of a format descriptor string – "IS"+CHR$(36)+"S"+CHR$(48) – indicating that each record consists of an integer and 2 strings of maximum length 32 and 48. As this occupies more than one line, how can one enter it or get it to scroll over? I hope some one will tell me it is just too simple and show me how to do it.

My other problem was with Polyzap – the assembler program. Here you have to enter a “Source File Specifier” but the manual doesn’t tell you (or, at least, I couldn’t find it) now to start. However, the answer is:–

Start with a file name eg. TEST.TX
Enter EDIT TEST.TX to which the monitor responds “Press space to continue”
When you do this, the screen clears and a flashing cursor appears in the top left hand corner
Enter your program in nmemonics to be assembled, editting it as you go along
You can then assemble it by entering PZAP TEST.TX

Now, if all is well, (and it generally isn’t) “PZAP” will assemble the program and output the results to the screen or the printer. If, as generally happens, there are errors, it will tell you what they are and you can start again. Now, I may not be doing it correctly and it has certainly caused me a lot of hassle, but, I am told, it is a very powerful assembler and you can throw away your ZEAP.

All in all I am really very pleased with PolyDos. It has tremendous potential and really makes the Nascom a production machine. I should be very interested to hear from any other Nascom user who has experimented with it.