80-Bus News

Bits & P.C.s Basic Toolkit

Just one last item: since getting a 64k RAM card, I have been trying EPROM based software in RAM and much of it works. However, some authors cannot resist putting little “fixes” in their programs to prevent them from running in RAM. Now I may be a bit naive, but I can’t for the life of me understand why they bother, unless it is that they reckon EPROM based programs are harder to copy than RAM based programs. Anyway, the Bits & P.C.s Basic toolkit is one of these programs, and there seem to be three such “fixes”. To eliminate these, place zeroes (NOPs) in the following locations B020, B021, B23E, B23F, B247, B248. If the program starts on a different 4k boundary, change the B’s to the appropriate value.

I hope that some of the information above will be of interest to you and your readers. Good luck with the magazine.

Clive A Graham G3XIG

BASIC Mods. & Microtype Cases

As a user not used to machine code, it may seem dumb to suggest, but, how about having all the readers rewrite the BASIC by offering their optimized Z80 solutions to the comprehensive listings of the 8080 codes available in the Microsoft BASIC? It may well be that this is what Crystal has already done, but knowing how well some of my better informed friends write in M-C, I have no doubt that there has to be a better (or even best) solution to every one of the seven hundred routines of the original Nascom BASIC, as well as to the forty-odd additional general and DOS routines which I have seen added since.

If this were undertaken by a group of readers I feel sure that this would be one of the largest and most interesting projects in microcomputing undertaken in recent years.

For those of us with Microtype cases for Nascoms 1 & 2, could I suggest that someone makes an ‘extension ring’ to fit between the upper and lower halves. Together with additional connectors there seems no reason why perhaps five or six cards can not be fitted – the fan is quite large enough to cope, the only limitation being the power supply which I believe could be uprated rather than replaced.

Bert Martin

DH back again.

Yes, a nice idea, although I doubt that the whole readership would either feel competent nor want to take part. This is the sort of thing that could easily be handled within a group. It sounds like the sort of thing that NAS-TUG, the Nascom Thames Valley User Group would dearly love to have a go at (how about it Mike?). I might add that Carl Lloyd-Parker is something like half way through the job of tearing the BASIC apart, converting it to Z80 mnemonics, commenting and labelling it, so far he has 170K of commented source, and he says that’s less than half of it. Personally I doubt that the finished code would be much if any shorter as the Microsoft BASIC is the product of many man-years work and must be fairly well optimized. Optimization to Z80 codes alone does not save all that much space. If any readers feel like having a go, drop us a line. If we get more than one reply we’ll put you all in touch.

The dear old Microtype case is fairly easily adapted and the idea of producing a ‘skirt’ to fit between the top and bottom halves is a good one, if not original. A couple of years ago I remember seeing one with the top and bottom halves separated by 2″ pillars and the resulting gap filled with fine black plastic mesh apparently bought from an ironmonger.