Scor­pio News


January–March 1987 – Volume 1. Issue 1.

Page 39 of 63

run, even though similar programs written when the system was much smaller worked well. Even more interestingly (I probably mean disgustingly), the system refuses to work at all without the I/O board. I suspect that either the the motherboard affecting the I/O control signals or the address bus. I meant to replace the mother board with a decent one ages ago, as it is just Vero board, but never got round to it due to the cost of the good ones. Any dealers got a Microcode 14 slot board left? [Ed. – see the Newburn advert. They have now taken over the production of this board.]

I have read and re-read all the various manuals, and am fairly sure all the boards are set up correctly with regard to 80-BUS signals such as NASIO and DBDR, which is an exercise I recommend for anyone who wants to test their patience and comprehension. My decision, until such time as I decide to pull the system to bits for maintenance, is to ignore all these problems, and program round them. Hence the need for assembly language speed in the Prestel software, in order that all the routines will be completed before incoming data has been lost. And if the Pluto board keeps the system waiting, I suppose I will just have to get the double speed processor option fitted, even if it is a silly price.


No, it doesn’t hurt your pocket, just your head. For very little money you get a good manual, a good screen editor and a good compiler. But the language itself rivals Forth for unreadability. (I know, you can write Forth so that other people can read it, but who actually does?)

The manual contains a quite helpful tutorial section, and the editor is excellent for programming use, as it has all the handy facilities like auto indentation. It will not do justification though, or word-wrap, like your favourite word processor. The really clever bit comes when the compiler finds a mistake in your C program. It re-enters the editor at or near the error, for you to fix it. Exit from the editor, and the compiler has another try. I like this, it saves a lot of the time usually spent giving commands to the compiler and editor on other systems! (I believe the newest version of the Hisoft Pascal compiler also does this, and will let you know when I get mine updated.)

The version of C implemented has no floating point numbers at all, just integers, which is a pity. It is a surprise too, given the good floating point support in the Pascal compiler. I just hope they will be doing a version for the Belectra board, as well as an ordinary Z80 version, when they do add floats. The system as supplied, and the programs it compiles, certainly work, and I am finding them helpful in my attempts to learn yet another language, but it is not a pretty language!


Mentioned above, I am writing a Prestel program to put a display on the Pluto board, instead of using the useful ‘Pretzel II’ I bought with the MODEM which uses the SVC (or an IVC) for its display. When finished, this will have quite a few fancy facilities, which would normally make it well worth trying to market the program. However, how many people have compatible hardware? If either of them is interested in a copy, they can contact me to arrange a swap for some Pluto program of their own writing. Anything pretty, like Mandelbrot set stuff, or flight simulators, would be most acceptable...


Correspondence about any of the above can be sent either to the Editor, if you want him to do something about it, or to me. Chris Blackmore, at __ ________ ______, Taunton, Somerset, ___ ___. Sometimes I fail to answer letters. Nobody is perfect. Although I do have telephone, I actually dislike using the things to speak to people, and would prefer not to be telephoned unless it is to offer me an amazing free gift or something!

Page 39 of 63