Hardware expansion is made standard by the use of NASBUS.
This is a bus standard, and this means that the signals
between all different expansion boards will meet this
standard. Note that the new NASCOM 2 computer plugs directly
into NASBUS, without the need for a buffer board, which is
an improvement. The NASCOM 2 still has the same screen
formatting and the same Z80 CPU, so it is highly compatible
with NASCOM 1.
(b) SOFTWARE – MONITORS
I hope that the
article on monitors
(later in this newsletter)
explaining the development which has resulted in NAS-SYS, has
answered many questions. Here is a brief summary. The
following group of monitors are all highly compatible.
NASBUG T1: This was replaced by T2, and no one has a NASBUG T1
any longer. (We hope!)
NASBUG T2: Standard 1K monitor.
B-BUG: 2K monitor, fully compatible with T2. It will run
all programs written for T2, without modification. It can read
and write tapes in LOAD/DUMP format, like T2, or in READ/WRITE
format. This monitor is not a NASCOM product.
NASBUG T4: 2K monitor, improved version of B-BUG. Same comments
apply as for B-BUG, One tiny difference – SRLOUT routine was
moved by one byte.
NAS-SYS 1 This new monitor is not directly compatible with
the earlier monitors. It is called NAS-SYS, meaning NASCOM
OPERATING SYSTEM, and has in fact been designed to provide for
easy upward compatibility in the future. Quite a few earlier
programs have been converted to NAS-SYS, (even including the
8K Basic!), and it has proved very easy in every case. When
NAS-SYS and its full documentation and listing are available,
I am sure it will be generally agreed that any inconvenience
is made worth while by the enormous improvements. If a user
has a large number of old programs, an old monitor can always
be plugged in to run them. In fact, even NASCOM 2 could be run
under NASBUG T2, if you really want to do this! In the future,
all programs will be NAS-SYS compatible, and there won’t be any
(c) SOFTWARE – TINY BASIC FROM NASCOM
The 2K Tiny Basic runs under NASBUG T2, B-BUG or NASBUG T4.
If NASBUG T2 is in use, programs are saved on cassette using
LOAD/DUMP format. If B-BUG or T4 are plugged in, then the
Basic automatically uses READ/WRITE format, which is, of course,