mechanical incompatiblity between 8″ and 5.25″ disks. Further, unfortunately,
there is lack of standardization between the various 5.25″ disk systems
themselves. Usually these varying standards have been chosen with care for very
valid technical reasons concerned with available disk space. However, it does
mean that whilst the programs are compatible, the disks on which programs and
data are stored may not be directly transferable from one machine to another.
On the brighter side, these various disk standards do not present much of
a problem to software suppliers who are capable of supplying software in almost
any disk standard. However, an obscure standard, in an unpopular format is less
likely to be attractive to a software supplier, meaning investment in copying
software is likely to show a lesser return for the effort involved compared with
the popular formats, suggesting that the prices for software in unpopular formats
are likely to be a little higher than those in the more popular formats. But
usually software houses offset the higher cost of unpopular formats against the
more popular formats, and charge a standard price for a given piece of software.
Likewise differing formats do not usually present a problem to end users
except where several different CP/M based machines are in use in one situation.
In this instance, the machine supplier is often in a position to supply the
necessary interchange software and hardware to allow the various machines to be
interconnected. In this way only one set of software need be purchased for
several machines, assuming the software licences allow multiple copies to be
To sum up then, CP/M itself remains transparent to the user, being solely
concerned with the efficient handling of the transfer of data and programs to and
from the disks. The BIOS handles all the communications with the outside world,
which it does to a greater or lesser degree of effectiveness depending upon the
ability of the manufacturer of the machine in question. (The effectiveness of the
BIOS is a good guide to the quality of support that may be expected from a
manufacturer.) The main benefit is the vast choice of standard software available
at reasonable prices, brought about by the compatibility that CP/M has introduced
throughout the small business system and system development markets.
Nascom 1 cased, PSU, Cottis Blandford cassette, Stuart colour board, Smart 1
puffer/32K RAM (with memory plague – no
instruments/knowledge to fix). £170 ONO.
Nascom 2 cased with 48K, Nas-Sys 3 and graphics.
printer, Hobbit digital
cassette system. Zeap, Nas-Dis, Debug, Sargon chess. Many games, spare cassettes,
books, magazines, manuals. Family circumstances force sale at £590.
Tel. Keith Brown, Colchester (____) ______
Teletype KSR 33. RS232 i/f fitted. Can be seen working on Nascom 2. Excellent
condition. £50. Keyboard with 80 good quality keys and case. £6.
Tel. Crowthorne ____.