<s>
The	O
Nascom	B-Operating_System
1	O
and	O
2	O
were	O
single-board	B-Device
computer	I-Device
kits	O
issued	O
in	O
the	O
United	O
Kingdom	O
in	O
1977	O
and	O
1979	O
,	O
respectively	O
,	O
based	O
on	O
the	O
Zilog	B-General_Concept
Z80	I-General_Concept
and	O
including	O
a	O
keyboard	B-Device
and	O
video	O
interface	O
,	O
a	O
serial	B-Protocol
port	I-Protocol
that	O
could	O
be	O
used	O
to	O
store	O
data	O
on	O
a	O
tape	B-Device
cassette	I-Device
using	O
the	O
Kansas	B-Device
City	I-Device
standard	I-Device
,	O
and	O
two	O
8-bit	O
parallel	O
ports	O
.	O
</s>
<s>
At	O
that	O
time	O
,	O
including	O
a	O
full	O
keyboard	B-Device
and	O
video	O
display	O
interface	O
was	O
uncommon	O
,	O
as	O
most	O
microcomputer	O
kits	O
were	O
then	O
delivered	O
with	O
only	O
a	O
hexadecimal	O
keypad	O
and	O
seven-segment	B-General_Concept
display	I-General_Concept
.	O
</s>
<s>
To	O
minimize	O
cost	O
,	O
the	O
buyer	O
had	O
to	O
assemble	O
a	O
Nascom	B-Operating_System
by	O
hand-soldering	O
about	O
3,000	O
joints	O
on	O
the	O
single	O
circuit	O
board	O
.	O
</s>
<s>
Later	O
on	O
,	O
a	O
pre-built	O
,	O
cased	O
machine	O
named	O
Nascom	B-Operating_System
3	O
was	O
available	O
;	O
this	O
used	O
the	O
Nascom	B-Operating_System
2	O
board	O
.	O
</s>
<s>
Model	O
Nascom	B-Operating_System
1	O
Nascom	B-Operating_System
2	O
Introduced	O
December	O
1977	O
December	O
1979	O
MSRP	O
(	O
price	O
)	O
£197.50	O
£225	O
CPU	O
( µP	O
)	O
Zilog	B-General_Concept
Z80	I-General_Concept
Zilog	B-General_Concept
Z80A	I-General_Concept
CPU	O
speed	O
2	O
MHz	O
2	O
or	O
4	O
MHz	O
(	O
switch	O
on	O
main	O
board	O
)	O
Monitor/OS	O
*	O
NAS-BUG	O
1	O
(	O
1	O
KB	O
EPROM	O
)	O
NAS-SYS	O
1	O
,	O
most	O
were	O
shipped	O
with	O
NAS-SYS	O
3	O
(	O
2	O
KB	O
ROM	O
)	O
RAM	O
2	O
KB	O
(	O
1	O
KB	O
used	O
for	O
display	O
)	O
,	O
exp	O
.	O
</s>
<s>
to	O
1	O
MB	O
Dimensions	O
8	O
"	O
x	O
10	O
"	O
(	O
main	O
board	O
)	O
8	O
"	O
x	O
12	O
"	O
(	O
main	O
board	O
)	O
Discontinued	O
1979	O
1983	O
*	O
A	O
debug	B-General_Concept
monitor	I-General_Concept
and	O
simple	O
operating	B-General_Concept
system	I-General_Concept
(	O
OS	O
)	O
was	O
included	O
with	O
the	O
devices	O
.	O
</s>
<s>
CP/M	B-Application
versions	O
1.4	O
,	O
2.2	O
and	O
3.0	O
were	O
also	O
available	O
later	O
.	O
</s>
<s>
The	O
history	O
of	O
Nascom	B-Operating_System
starts	O
with	O
the	O
history	O
of	O
John	O
A	O
.	O
Marshall	O
.	O
</s>
<s>
Pitman	O
was	O
the	O
marketing	O
manager	O
for	O
Mostek	O
,	O
which	O
had	O
recently	O
become	O
a	O
second	O
source	O
for	O
Zilog	O
's	O
Z80	B-General_Concept
processor	O
.	O
</s>
<s>
Pitman	O
put	O
Marshall	O
in	O
touch	O
with	O
a	O
design	O
consultant	O
named	O
Chris	O
Shelton	O
and	O
,	O
in	O
the	O
Spring	O
of	O
1977	O
,	O
Marshall	O
commissioned	O
Shelton	O
Instruments	O
to	O
design	O
the	O
Nascom	B-Operating_System
1	O
.	O
</s>
<s>
Most	O
of	O
the	O
details	O
of	O
the	O
Nascom	B-Operating_System
design	O
were	O
described	O
in	O
a	O
series	O
of	O
articles	O
by	O
Pitman	O
that	O
appeared	O
in	O
Wireless	O
World	O
between	O
November	O
1977	O
and	O
January	O
1979	O
.	O
</s>
<s>
On	O
Saturday	O
,	O
26	O
November	O
1977	O
,	O
Lynx	O
Electronics	O
launched	O
the	O
Nascom	B-Operating_System
1	O
at	O
their	O
"	O
Home	O
Microcomputer	O
Symposium	O
"	O
at	O
Wembley	O
Conference	O
Centre	O
,	O
London	O
.	O
</s>
<s>
The	O
event	O
included	O
a	O
raffle	O
for	O
a	O
Nascom	B-Operating_System
1	O
computer	O
kit	O
.	O
</s>
<s>
photograph	O
for	O
that	O
issue	O
(	O
though	O
not	O
with	O
the	O
final	O
keyboard	B-Device
)	O
.	O
</s>
<s>
Ltd	O
)	O
described	O
the	O
origins	O
and	O
history	O
of	O
the	O
Nascom	B-Operating_System
1	O
design	O
.	O
</s>
<s>
In	O
January	O
1978	O
,	O
the	O
Lynx	O
Electronics	O
advert	O
in	O
Practical	O
Electronics	O
listed	O
the	O
Nascom	B-Operating_System
1	O
in	O
addition	O
to	O
their	O
traditional	O
list	O
of	O
electronic	O
components	O
.	O
</s>
<s>
By	O
February	O
1978	O
and	O
thereafter	O
the	O
whole	O
of	O
their	O
advert	O
was	O
devoted	O
to	O
the	O
Nascom	B-Operating_System
1	O
.	O
</s>
<s>
The	O
launch	O
price	O
for	O
the	O
Nascom	B-Operating_System
1	O
was	O
£197.50	O
plus	O
8%	O
VAT	O
,	O
in	O
kit	O
form	O
.	O
</s>
<s>
The	O
kit	O
included	O
keyboard	B-Device
and	O
sockets	O
for	O
some	O
(	O
but	O
not	O
all	O
)	O
of	O
the	O
ICs	O
.	O
</s>
<s>
By	O
July	O
1978	O
,	O
The	O
Micronics	O
Company	O
was	O
advertising	O
a	O
cased	O
,	O
built	O
and	O
tested	O
Nascom	B-Operating_System
1	O
(	O
with	O
power	O
supply	O
)	O
for	O
£399	O
+	O
VAT	O
.	O
</s>
<s>
The	O
advert	O
does	O
not	O
name	O
the	O
machine	O
as	O
a	O
Nascom	B-Operating_System
1	O
but	O
the	O
specification	O
is	O
identical	O
.	O
</s>
<s>
By	O
January	O
1979	O
,	O
Lynx	O
Electronics	O
had	O
appointed	O
multiple	O
dealers	O
in	O
the	O
UK	O
and	O
were	O
advertising	O
as	O
Nascom	B-Operating_System
Microcomputers	O
,	O
with	O
the	O
"	O
nm	O
"	O
logo	O
.	O
</s>
<s>
In	O
September	O
1979	O
,	O
PCW	O
reported	O
that	O
Grovewood	O
Securities	O
had	O
invested	O
£	O
500,000	O
in	O
Nascom	B-Operating_System
.	O
</s>
<s>
The	O
same	O
article	O
reported	O
that	O
PAL	B-Language
full-colour	O
support	O
would	O
arrive	O
for	O
the	O
Nascom	B-Operating_System
by	O
"	O
the	O
new	O
year	O
"	O
.	O
</s>
<s>
In	O
September	O
1979	O
,	O
the	O
Nascom	B-Operating_System
2	O
(	O
kit	O
)	O
was	O
announced	O
with	O
a	O
list	O
price	O
of	O
£295	O
+	O
VAT	O
.	O
</s>
<s>
Then	O
,	O
Nascom	B-Operating_System
were	O
hit	O
by	O
a	O
shortage	O
of	O
Mostek	O
MK4118	O
1Kx8	O
RAM	O
devices	O
.	O
</s>
<s>
10	O
devices	O
were	O
required	O
per	O
Nascom	B-Operating_System
2	O
(	O
1	O
each	O
for	O
video	O
RAM	O
and	O
workspace	O
RAM	O
respectively	O
,	O
8	O
for	O
user	O
RAM	O
)	O
but	O
Nascom	B-Operating_System
were	O
only	O
able	O
to	O
source	O
5,000	O
parts	O
.	O
</s>
<s>
By	O
November	O
1979	O
Nascom	B-Operating_System
had	O
decided	O
to	O
relaunch	O
the	O
product	O
with	O
a	O
16Kbyte	O
DRAM	O
board	O
and	O
NASBUS	O
interconnect	O
but	O
to	O
keep	O
the	O
price	O
at	O
£295	O
+	O
VAT	O
.	O
</s>
<s>
This	O
arrangement	O
only	O
required	O
2	O
MK4118	O
devices	O
,	O
allowing	O
Nascom	B-Operating_System
to	O
ship	O
2,500	O
systems	O
.	O
</s>
<s>
By	O
December	O
1979	O
,	O
PCW	O
reported	O
that	O
the	O
first	O
deliveries	O
of	O
the	O
Nascom	B-Operating_System
2	O
were	O
going	O
out	O
.	O
</s>
<s>
On	O
23	O
May	O
1980	O
,	O
Nascom	B-Operating_System
reported	O
that	O
it	O
had	O
asked	O
Grovewood	O
Securities	O
Ltd	O
to	O
appoint	O
a	O
receiver	O
after	O
it	O
had	O
been	O
unable	O
to	O
secure	O
further	O
investment	O
.	O
</s>
<s>
Nascom	B-Operating_System
continued	O
to	O
trade	O
in	O
receivership	O
.	O
</s>
<s>
In	O
July	O
1981	O
,	O
PCW	O
reported	O
that	O
Nascom	B-Operating_System
had	O
been	O
bought	O
by	O
Lucas	O
Industries	O
;	O
the	O
same	O
issue	O
contained	O
a	O
full-page	O
advert	O
under	O
the	O
name	O
"	O
Nascom	B-Operating_System
Microcomputers	O
.	O
</s>
<s>
In	O
December	O
1981	O
,	O
the	O
Nascom	B-Operating_System
3	O
was	O
launched	O
.	O
</s>
<s>
This	O
was	O
basically	O
a	O
cased	O
Nascom	B-Operating_System
2	O
with	O
some	O
expansion	O
boards	O
.	O
</s>
<s>
In	O
June	O
1984	O
,	O
the	O
final	O
issue	O
of	O
the	O
Nascom	B-Operating_System
Newsletter	O
was	O
published	O
.	O
</s>
<s>
In	O
January	O
1985	O
,	O
PCW	O
published	O
a	O
letter	O
from	O
Lucas	O
Nascom	B-Operating_System
stating	O
that	O
,	O
while	O
the	O
Nascom	B-Operating_System
1	O
had	O
been	O
discontinued	O
,	O
the	O
Nascom	B-Operating_System
2	O
and	O
Nascom	B-Operating_System
3	O
were	O
still	O
in	O
production	O
.	O
</s>
<s>
A	O
Nascom	B-Operating_System
advert	O
in	O
January	O
1980	O
claimed	O
"	O
over	O
15,000	O
systems	O
in	O
operation	O
world-wide	O
"	O
.	O
</s>
<s>
Nascom	B-Operating_System
had	O
shipped	O
over	O
35,000	O
Nascom	B-Operating_System
1	O
and	O
Nascom	B-Operating_System
2	O
systems	O
,	O
all	O
in	O
kit	O
form	O
.	O
</s>
<s>
The	O
Nascom	B-Operating_System
1	O
and	O
Nascom	B-Operating_System
2	O
were	O
supplied	O
with	O
full	O
documentation	O
including	O
circuit	O
schematics	O
,	O
construction	O
guide	O
,	O
datasheets	O
for	O
some	O
components	O
and	O
assembly	O
listing	O
for	O
the	O
ROM	O
monitor	O
.	O
</s>
<s>
An	O
annotated	O
disassembly	O
listing	O
of	O
the	O
Nascom	B-Operating_System
2	O
Microsoft	O
ROM	O
BASIC	O
was	O
published	O
and	O
the	O
code	O
was	O
subsequently	O
re-purposed	O
in	O
retrocomputing	O
projects	O
such	O
as	O
Grant	O
Searle	O
's	O
Multicomp	O
and	O
Spencer	O
Owen	O
's	O
RC2014	O
.	O
</s>
<s>
The	O
Nascom	B-Operating_System
1	O
and	O
Nascom	B-Operating_System
2	O
hardware	O
designs	O
had	O
these	O
features	O
in	O
common	O
:	O
</s>
<s>
RS232	O
terminal	O
or	O
printer	O
)	O
or	O
to	O
save	O
and	O
load	O
data	O
using	O
a	O
domestic	O
compact	B-Device
cassette	I-Device
recorder	O
.	O
</s>
<s>
An	O
LED	O
(	O
"	O
HALT	O
"	O
)	O
on	O
the	O
Z80-CPU	O
"	O
/HALT	O
"	O
output	O
,	O
to	O
provide	O
a	O
visual	O
indication	O
that	O
the	O
CPU	O
was	O
halted	O
.	O
</s>
<s>
The	O
I/O	O
address	O
map	O
was	O
common	O
between	O
the	O
Nascom	B-Operating_System
1	O
and	O
Nascom	B-Operating_System
2	O
designs	O
,	O
and	O
the	O
memory	O
address	O
map	O
of	O
the	O
Nascom	B-Operating_System
2	O
was	O
a	O
superset	O
of	O
the	O
Nascom	B-Operating_System
1	O
memory	O
address	O
map	O
;	O
this	O
allowed	O
a	O
high	O
degree	O
of	O
software	O
compatibility	O
between	O
the	O
two	O
machines	O
.	O
</s>
<s>
The	O
Nascom	B-Operating_System
1	O
was	O
implemented	O
entirely	O
using	O
off-the-shelf	O
integrated-circuits	O
and	O
other	O
electronic	O
components	O
.	O
</s>
<s>
The	O
Nascom	B-Operating_System
2	O
used	O
4	O
,	O
16-pin	O
bipolar	O
PROMs	B-General_Concept
which	O
acted	O
as	O
glue	O
logic	O
for	O
decode	O
functions	O
(	O
"	O
N2MD	O
"	O
for	O
memory	O
decode	O
,	O
"	O
N2IO	O
"	O
for	O
I/O	O
decode	O
,	O
"	O
N2V	O
"	O
for	O
video	O
decode	O
and	O
N2DB	O
"	O
for	O
data	O
bus	O
buffer	O
control	O
)	O
.	O
</s>
<s>
The	O
Nascom	B-Operating_System
2	O
had	O
these	O
additional	O
features	O
that	O
were	O
not	O
present	O
on	O
the	O
Nascom	B-Operating_System
1	O
:	O
</s>
<s>
A	O
reset-jump	O
circuit	O
that	O
allowed	O
the	O
Z80-CPU	O
to	O
start	O
execution	O
from	O
any	O
4-Kbyte	O
boundary	O
after	O
reset	O
(	O
the	O
Z80-CPU	O
usually	O
fetches	O
from	O
address	O
0	O
after	O
reset	O
)	O
.	O
</s>
<s>
Microsoft	B-Language
BASIC	I-Language
in	O
an	O
8Kbyte	O
ROM	O
.	O
</s>
<s>
Two	O
groups	O
of	O
4	O
uncommitted	O
24-pin	O
DIL	B-Algorithm
sockets	O
.	O
</s>
<s>
The	O
Nascom	B-Operating_System
1	O
used	O
DIL	B-Algorithm
sockets	O
for	O
making	O
external	O
connections	O
.	O
</s>
<s>
The	O
photo	O
shows	O
4	O
sockets	O
,	O
used	O
for	O
keyboard	B-Device
,	O
serial	O
(	O
cassette	O
and/or	O
teletype/printer	O
)	O
,	O
PIO	O
port	O
A	O
,	O
PIO	O
port	O
B	O
.	O
</s>
<s>
The	O
Nascom	B-Operating_System
keyboards	B-Device
used	O
Licon	O
solid-state	O
(	O
induction	O
transformer	O
)	O
key	O
switches	O
in	O
a	O
matrix	O
arrangement	O
which	O
was	O
scanned	O
under	O
software	O
control	O
.	O
</s>
<s>
A	O
separate	O
,	O
conventional	O
,	O
key	O
switch	O
was	O
provided	O
on	O
the	O
keyboard	B-Device
for	O
hardware	O
reset	O
.	O
</s>
<s>
The	O
Nascom	B-Operating_System
1	O
had	O
47	O
keys	O
.	O
</s>
<s>
The	O
Nascom	B-Operating_System
2	O
had	O
10	O
additional	O
keys	O
(	O
GRAPH	O
,	O
which	O
toggled	O
bit	O
7	O
,	O
CTRL	O
,	O
a	O
second	O
SHIFT	O
key	O
,	O
4	O
cursor	O
direction	O
keys	O
,	O
LF/CH	O
and	O
keys	O
for	O
[	O
and	O
]	O
)	O
.	O
</s>
<s>
The	O
Nascom	B-Operating_System
2	O
keyboard	B-Device
was	O
designed	O
to	O
be	O
mounted	O
at	O
an	O
angle	O
;	O
it	O
had	O
angled	O
key-caps	O
which	O
were	O
horizontal	O
when	O
the	O
keyboard	B-Device
itself	O
was	O
mounted	O
at	O
an	O
angle	O
.	O
</s>
<s>
The	O
key-caps	O
on	O
the	O
Nascom	B-Operating_System
1	O
were	O
not	O
angled	O
(	O
see	O
photo	O
)	O
.	O
</s>
<s>
The	O
keyboard	B-Device
was	O
always	O
supplied	O
assembled	O
,	O
even	O
when	O
the	O
rest	O
of	O
the	O
Nascom	B-Operating_System
was	O
supplied	O
as	O
a	O
kit	O
.	O
</s>
<s>
The	O
Nascom	B-Operating_System
1	O
used	O
a	O
16-pin	O
IC-style	O
DIL	B-Algorithm
socket	O
at	O
each	O
end	O
of	O
the	O
connection	O
from	O
the	O
keyboard	B-Device
to	O
the	O
computer	O
main	O
board	O
.	O
</s>
<s>
The	O
Nascom	B-Operating_System
2	O
used	O
a	O
0.1	O
"	O
2x8	O
male	O
header	O
(	O
16	O
pins	O
total	O
)	O
at	O
each	O
end	O
.	O
</s>
<s>
In	O
each	O
case	O
,	O
the	O
connectors	O
use	O
the	O
same	O
physical	O
ordering	O
of	O
signals	O
but	O
the	O
pin	O
numbers	O
do	O
not	O
correspond	O
(	O
because	O
DIL	B-Algorithm
sockets	O
and	O
IDC	O
headers	O
use	O
different	O
numbering	O
conventions	O
)	O
.	O
</s>
<s>
The	O
Nascom	B-Operating_System
2	O
keyboard	B-Device
has	O
an	O
additional	O
"	O
sense	O
"	O
output	O
.	O
</s>
<s>
Both	O
Nascom	B-Operating_System
1	O
and	O
Nascom	B-Operating_System
2	O
main	O
boards	O
had	O
connections	O
to	O
the	O
keyboard	B-Device
connectors	O
that	O
were	O
unused	O
on	O
the	O
keyboard	B-Device
.	O
</s>
<s>
On	O
the	O
Nascom	B-Operating_System
2	O
,	O
this	O
included	O
a	O
connection	O
to	O
the	O
/NMI	O
(	O
non-maskable	O
interrupt	O
)	O
signal	O
.	O
</s>
<s>
The	O
display	O
of	O
the	O
Nascom	B-Operating_System
1	O
and	O
2	O
was	O
memory-mapped	O
and	O
consisted	O
of	O
16	O
rows	O
of	O
48	O
characters	O
.	O
</s>
<s>
Due	O
to	O
an	O
idiosyncrasy	O
of	O
the	O
video	O
memory	O
decoding	O
on	O
the	O
Nascom	B-Operating_System
1	O
(	O
which	O
was	O
then	O
retained	O
on	O
the	O
Nascom	B-Operating_System
2	O
)	O
,	O
the	O
lines	O
were	O
decoded	O
discontiguously	O
,	O
with	O
the	O
top	O
line	O
of	O
the	O
display	O
being	O
the	O
16th	O
region	O
of	O
memory	O
.	O
</s>
<s>
The	O
top	O
line	O
was	O
not	O
scrolled	O
,	O
except	O
by	O
the	O
Nascom	B-Operating_System
CP/M	B-Application
implementation	O
.	O
</s>
<s>
The	O
Nascom	B-Operating_System
1	O
used	O
a	O
MCM6576P	O
character	O
generator	O
to	O
display	O
128	O
characters	O
(	O
bit	O
7	O
of	O
the	O
memory	O
was	O
ignored	O
)	O
.	O
</s>
<s>
The	O
Nascom	B-Operating_System
2	O
used	O
an	O
identical	O
character	O
set	O
but	O
implemented	O
it	O
in	O
a	O
ROM	O
that	O
was	O
footprint	O
compatible	O
with	O
a	O
2716	O
2Kbyte	O
device	O
.	O
</s>
<s>
The	O
Nascom	B-Operating_System
2	O
allowed	O
a	O
second	O
2Kbyte	O
character	O
generator	O
ROM	O
(	O
or	O
EPROM	O
)	O
to	O
be	O
fitted	O
(	O
approximate	O
price	O
£20	O
in	O
1980	O
)	O
.	O
</s>
<s>
The	O
built-in	O
Microsoft	B-Language
BASIC	I-Language
(	O
8K	O
ROM	O
)	O
interpreter	O
could	O
use	O
these	O
graphics	O
to	O
create	O
a	O
crude	O
,	O
blocky	O
96×48	O
graphics	O
display	O
.	O
</s>
<s>
On	O
the	O
Nascom	B-Operating_System
1	O
,	O
all	O
16	O
rows	O
of	O
the	O
character	O
were	O
displayed	O
,	O
so	O
that	O
the	O
whole	O
image	O
occupied	O
16*16	O
=	O
256	O
rows	O
.	O
</s>
<s>
On	O
the	O
Nascom	B-Operating_System
2	O
,	O
the	O
top	O
12	O
or	O
14	O
rows	O
of	O
the	O
character	O
were	O
displayed	O
(	O
controlled	O
by	O
the	O
setting	O
of	O
a	O
switch/jumper	O
on	O
the	O
main	O
board	O
)	O
.	O
</s>
<s>
On	O
the	O
Nascom	B-Operating_System
1	O
this	O
gave	O
rise	O
to	O
white	O
flicker	O
on	O
the	O
screen	O
that	O
was	O
termed	O
"	O
snow	O
"	O
.	O
</s>
<s>
The	O
International	O
Nascom	B-Operating_System
Microcomputer	O
Club	O
(	O
INMC	O
)	O
published	O
a	O
"	O
snow	O
plough	O
"	O
design	O
that	O
reduced	O
the	O
effect	O
by	O
blanking	O
the	O
video	O
when	O
simultaneous	O
access	O
occurred	O
.	O
</s>
<s>
The	O
Nascom	B-Operating_System
2	O
used	O
a	O
slightly	O
different	O
design	O
but	O
still	O
allowed	O
contention	O
to	O
occur	O
,	O
this	O
time	O
giving	O
rise	O
to	O
black	O
flicker	O
(	O
blanking	O
)	O
on	O
the	O
screen	O
.	O
</s>
<s>
On	O
the	O
earliest	O
machines	O
with	O
limited	O
memory	O
this	O
meant	O
writing	O
Z80	B-General_Concept
assembly	B-Language
language	I-Language
on	O
paper	O
,	O
assembling	O
it	O
by	O
hand	O
and	O
then	O
using	O
the	O
monitor	O
program	O
to	O
enter	O
it	O
in	O
Hexadecimal	O
format	O
.	O
</s>
<s>
The	O
Nascom	B-Operating_System
1	O
provided	O
2	O
,	O
24-pin	O
0.6	O
"	O
-pitch	O
DIL	B-Algorithm
sockets	O
for	O
ROM	O
memory	O
,	O
each	O
wired	O
to	O
accept	O
a	O
2708	O
1Kbyte	O
device	O
.	O
</s>
<s>
The	O
first	O
monitor	O
program	O
on	O
the	O
Nascom	B-Operating_System
1	O
was	O
named	O
NAS-BUG	O
and	O
was	O
supplied	O
as	O
a	O
single	O
1Kbyte	O
2708	O
EPROM	O
.	O
</s>
<s>
The	O
Nascom	B-Operating_System
2	O
provided	O
1	O
,	O
24-pin	O
0.6	O
"	O
-pitch	O
DIL	B-Algorithm
socket	O
for	O
ROM	O
memory	O
(	O
other	O
sockets	O
on	O
the	O
Nascom	B-Operating_System
2	O
board	O
could	O
also	O
be	O
configured	O
to	O
accommodate	O
ROMs	O
)	O
,	O
wired	O
to	O
accept	O
a	O
5V	O
2716	O
2Kbyte	O
device	O
.	O
</s>
<s>
Nascom	B-Operating_System
2	O
kits	O
were	O
initially	O
provided	O
with	O
NAS-SYS	O
1	O
in	O
masked	O
ROM	O
(	O
the	O
photo	O
shows	O
that	O
at	O
least	O
2	O
date-codes	O
exist	O
for	O
these	O
ROMs	O
)	O
.	O
</s>
<s>
NAS-SYS	O
1	O
was	O
the	O
only	O
Nascom	B-Operating_System
monitor	O
ROM	O
to	O
be	O
supplied	O
as	O
masked	O
ROM	O
;	O
all	O
other	O
versions	O
were	O
supplied	O
as	O
EPROMs	O
.	O
</s>
<s>
All	O
of	O
the	O
debug	B-General_Concept
monitors	I-General_Concept
provided	O
similar	O
capabilities	O
,	O
with	O
different	O
levels	O
of	O
sophistication	O
:	O
</s>
<s>
As	O
the	O
user-base	O
grew	O
,	O
user-group	O
magazines	O
published	O
type-in	O
programs	O
either	O
in	O
assembly	B-Language
language	I-Language
or	O
as	O
hexadecimal	O
dumps	O
or	O
(	O
later	O
)	O
in	O
BASIC	O
.	O
</s>
<s>
Computing	O
magazines	O
such	O
as	O
Personal	O
Computer	O
World	O
,	O
Practical	O
Computing	O
and	O
Computing	O
Today	O
published	O
articles	O
and	O
software	O
specifically	O
for	O
the	O
Nascom	B-Operating_System
computers	O
.	O
</s>
<s>
Later	O
,	O
commercial	O
software	O
was	O
made	O
available	O
either	O
on	O
cassette	B-Device
tape	I-Device
or	O
programmed	O
into	O
one	O
or	O
more	O
EPROMs	O
(	O
usually	O
1kbyte	O
2708	O
devices	O
)	O
.	O
</s>
<s>
The	O
predecessor	O
of	O
Borland	O
's	O
very	O
successful	O
Turbo	B-Application
Pascal	I-Application
compiler	B-Language
and	O
integrated	B-Application
development	I-Application
environment	I-Application
(	O
IDE	O
)	O
for	O
CP/M	B-Application
and	O
DOS	O
was	O
developed	O
by	O
Anders	O
Hejlsberg	O
of	O
Blue	O
Label	O
Software	O
for	O
the	O
Nascom	B-Operating_System
2	O
,	O
under	O
the	O
name	O
Blue	O
Label	O
Software	O
Pascal	O
,	O
or	O
BLS	O
Pascal	O
.	O
</s>
<s>
In	O
1979	O
the	O
Nascom	B-Operating_System
2	O
came	O
with	O
an	O
onboard	O
ROM	O
with	O
early	O
Microsoft	B-Language
Basic	I-Language
8k	O
interpreter	O
.	O
</s>
<s>
Nascom	B-Operating_System
defined	O
an	O
expansion	O
bus	O
,	O
named	O
NAS-BUS	O
,	O
allowing	O
many	O
other	O
cards	O
to	O
be	O
added	O
to	O
the	O
Nascom	B-Operating_System
.	O
</s>
<s>
The	O
Nascom	B-Operating_System
1	O
required	O
a	O
buffer	O
board	O
to	O
generate	O
the	O
NAS-BUS	O
;	O
the	O
buffer	O
board	O
was	O
connected	O
to	O
a	O
43-way	O
(	O
42-way	O
plus	O
polarising	O
slot	O
)	O
0.1	O
"	O
pitch	O
tinned	O
edge	O
connector	O
on	O
its	O
PCB	O
.	O
</s>
<s>
The	O
Nascom	B-Operating_System
2	O
generated	O
the	O
NAS-BUS	O
directly	O
on	O
an	O
80-way	O
(	O
79-way	O
plus	O
polarising	O
slot	O
)	O
0.1	O
"	O
pitch	O
gold-plated	O
edge	O
connector	O
on	O
its	O
PCB	O
.	O
</s>
<s>
Other	O
manufacturers	O
(	O
including	O
Gemini	O
and	O
MAP80	O
Systems	O
)	O
produced	O
their	O
own	O
80-bus	O
CPU	O
boards	O
,	O
which	O
allowed	O
an	O
entire	O
non-Nascom	O
system	O
to	O
be	O
built	O
.	O
</s>
<s>
An	O
80-bus	O
compatible	O
network	O
card	O
enabled	O
both	O
Nascom	B-Operating_System
and	O
Gemini	O
computers	O
to	O
be	O
used	O
in	O
office	O
environments	O
.	O
</s>
<s>
In	O
the	O
early	O
1980s	O
,	O
one	O
of	O
the	O
first	O
generation	O
of	O
computer	O
retailers	O
,	O
Kenilworth	O
Computers	O
,	O
released	O
a	O
version	O
of	O
the	O
Nascom	B-Operating_System
microcomputer	O
with	O
the	O
selling	O
point	O
that	O
it	O
was	O
robust	O
enough	O
to	O
be	O
used	O
by	O
agriculture	O
.	O
</s>
<s>
Movement	O
Computer	O
Systems	O
used	O
the	O
Nascom	B-Operating_System
2	O
as	O
the	O
controller	O
for	O
their	O
MCDU1	O
and	O
MCDU2	O
drum	O
machines	O
.	O
</s>
