80-Bus News


January–March 1982, Volume 1, Issue 1

Page 14 of 55



<P et Se ey te ee

This is a program that runs on a Nascom 2 under CP/M, and pretends to be an improved version of Nas-Sys. The improvements consist of additional routines to move sections of the memory to disk, and read them back. The details of how to do this have appeared in the second issue of Micropower, a Magazine that says quite kind things about this magazine. As quite a lot of typing is needed, I will repeat here the offer I made in the Micropower article. Anyone who wants a copy of MONITOR.COM should send a disk, initialised for their system, plus a pound for postage, packing and not a lot of profit! Frankly, if you have no desire to use all the programs you wrote before you had your disk drive/s, or have a hardware way of switching to Nas-Sys, you don’t need this, so there! As an aside, I should mention that the rather primitive disk read and write routines I have written for the program don’t work for files longer than 16K. There, saved you the effort of writing to tell me!

For those who have lost INMC80-3, my name and address is: Chris Blackmore, 31 Herne Rise, Ilminster, Somerset, TA19 OHH


I just converted my EPROM Naspen to use the somewhat altered screen addressing of my system, in a RAM version loaded from disk by MONITOR.COM, and am rather pleased with myself! I wanted Diskpen, but there was no more cash to hand, so that was that, for a while. See later in the episode for details of another editor.

Of course, the files produced by my rather clumsy modifications are not quite CP/M compatible, having only Carriage Returns where there should also be Line Feeds. I get round this slight problem by using another program, whose function is to grab the Naspen file left in memory by the converted Naspen, add line feeds to it and store it as a CP/M file on disk. They can then be edited again with CP/M compatible editors, if necessary, though I keep my working copy on tape, ready to send in for publication.

Meanwhile, here for your interest, if any, are the changes to Naspen needed if the VDU RAM in your system is at F800H:

Address Change this To this B869 11 DO OB 11 DO FB B8A2 11 09 08 11 09 F8 B9IC 11 EA OB 11 EA FB B94D 21 8A OB 21 8A FB B953 11 4A OB 11 4A FB, | BB98 21 80 OA 21 80 FA BBD3 21 8A OB 21 8A FB BBEL 11 8A OB 11 8A FB BBF5 21 8B OB 21 8B FB BCO2 21 90 OB 21 90 FB BEB6 11 E3 OB ll E3 FB

One slightly unexpected problem I had during the conversion of Naspen was that the board I was reading it from, a Merseyside Nascom Users Group EPROM board, doesn’t seem to send out a RAMDIS signal. Filling the RAM addresses concerned with FF’s enabled me to copy the program to an area that wasn’t duplicated by more than one board. You may well ask how much RAM there is on the new system... I hardly like to go on about this, but it is a certain manufacturer’s 64K page mode job, and what was memory plague, anyway? I should know better than to write that, as I am proposing to reassemble the venerable Marvin soon, so that I can play at Nascom 1/2 system games.

This is an OCR’d version of the scanned page and likely contains recognition errors.

Page 14 of 55