Letters

About software standards

1) I am writing in response to your plea for comments on Mr. O’Farrell article re:standardised extensions to Nas-Sys. I agree entirely with hie motives in providing standard calls for add-ons but I would like to suggest a few alterations to his schene

a) Graphic boards

Rather than separate SCAL calls for line, circle, etc., would it not be better to use one SCAL GRAF and load up the arguments and/or registers?

b) Floating Point Handling

Whilst floating point routines have been published in many places, they are still not widely available to everyone.

I believe extended calls to Nas-Sys should include floating point arithmetic and functions as well as perhaps extended precision integers. In doing this it will turn Sys into s ‘software bus’ onto which can be tacked all manner of language and arithmetic applications.

c) Nas-Sys (COM) Naughties

Many moons ago, in the days when Z**l’s weren’t around, there was an article in INMC (issue 5 or 6 I think) entitled ‘Nas-Sys Naughties’. The purpose of it was to ward off people making direct calls to Nas-Sys as they had done with the Nas-Bugs. May I now suggest another naughty – Direct Keyboard Scans!!!

Many games programs and certain languages, ie BASIC and BLS Pascal, scan the keyboard directly. (BLS Pascal even makes a direct call to Nas-Sys). This practice is all very well and good on a Nascom but it is perfectly possible to run Sys on a Gemini by fudging the video RAM (see Richard Beal’s program in 80-Bus News).

So, in conclusion, I would repeat my wish that Sys should act as a ‘software bus’ running the ‘hardware bus’ we all know.

R.D.E. Brown,
Landon ___

2) The proposal by Mr. O’Farrell in the Nascom Newsletter Vol.3, No.1 was a very good idea. A lot of people have already added new routines to their Nas-Sys. I know that Polydos uses its own set of new routine numbers and I think that Nasdos does the same. It would be nice if we could get some standard out of it.

But I think that there is another problem. Where in memory should these extra routines be placed? Somewhere in the top of memory most people would say, but I think that this is only half a solution. Why not place the whole monitor on another page? This is what I have done. Nas-Sys is placed on G803 EPROM board (but I think that it should be a simple matter to modify the CPU-board such that it could be paged in and out). The monitor pages itself in and out when Nas-Sys routines are