<s>
The	O
British	B-Device
Broadcasting	I-Device
Corporation	I-Device
Microcomputer	I-Device
System	I-Device
,	O
or	O
BBC	B-Device
Micro	I-Device
,	O
is	O
a	O
series	O
of	O
microcomputers	B-Architecture
and	O
associated	O
peripherals	O
designed	O
and	O
built	O
by	O
Acorn	O
Computers	O
in	O
the	O
1980s	O
for	O
the	O
BBC	B-Device
Computer	I-Device
Literacy	I-Device
Project	I-Device
.	O
</s>
<s>
Designed	O
with	O
an	O
emphasis	O
on	O
education	O
,	O
it	O
was	O
notable	O
for	O
its	O
ruggedness	O
,	O
expandability	O
,	O
and	O
the	O
quality	O
of	O
its	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
After	O
the	O
Literacy	O
Project	O
's	O
call	O
for	O
bids	O
for	O
a	O
computer	O
to	O
accompany	O
the	O
TV	O
programmes	O
and	O
literature	O
,	O
Acorn	O
won	O
the	O
contract	O
with	O
the	O
Proton	O
,	O
a	O
successor	O
of	O
its	O
Atom	B-Device
computer	O
prototyped	O
at	O
short	O
notice	O
.	O
</s>
<s>
Renamed	O
the	O
BBC	B-Device
Micro	I-Device
,	O
the	O
system	O
was	O
adopted	O
by	O
most	O
schools	O
in	O
the	O
United	O
Kingdom	O
,	O
changing	O
Acorn	O
's	O
fortunes	O
.	O
</s>
<s>
Acorn	O
later	O
employed	O
the	O
machine	O
to	O
simulate	O
and	O
develop	O
the	O
ARM	B-Architecture
architecture	I-Architecture
.	O
</s>
<s>
While	O
nine	O
models	O
were	O
eventually	O
produced	O
with	O
the	O
BBC	O
brand	O
,	O
the	O
phrase	O
"	O
BBC	B-Device
Micro	I-Device
"	O
is	O
usually	O
used	O
colloquially	O
to	O
refer	O
to	O
the	O
first	O
four	O
(	O
Model	O
A	O
,	O
B	O
,	O
B+64	O
and	O
B+128	O
)	O
;	O
subsequent	O
BBC	O
models	O
are	O
considered	O
part	O
of	O
the	O
BBC	B-Device
Master	I-Device
and	O
Acorn	B-Device
's	I-Device
Archimedes	I-Device
series	O
.	O
</s>
<s>
During	O
the	O
early	O
1980s	O
,	O
the	O
BBC	O
started	O
what	O
became	O
known	O
as	O
the	O
BBC	B-Device
Computer	I-Device
Literacy	I-Device
Project	I-Device
.	O
</s>
<s>
The	O
project	O
was	O
initiated	O
partly	O
in	O
response	O
to	O
an	O
ITV	O
documentary	O
series	O
The	O
Mighty	O
Micro	O
,	O
in	O
which	O
Christopher	O
Evans	O
of	O
the	O
UK	O
's	O
National	O
Physical	O
Laboratory	O
predicted	O
the	O
coming	O
microcomputer	B-Architecture
revolution	O
and	O
its	O
effect	O
on	O
the	O
economy	O
,	O
industry	O
,	O
and	O
lifestyle	O
of	O
the	O
United	O
Kingdom	O
.	O
</s>
<s>
The	O
BBC	O
wanted	O
to	O
base	O
its	O
project	O
on	O
a	O
microcomputer	B-Architecture
capable	O
of	O
performing	O
various	O
tasks	O
which	O
they	O
could	O
then	O
demonstrate	O
in	O
the	O
TV	O
series	O
The	O
Computer	O
Programme	O
.	O
</s>
<s>
The	O
list	O
of	O
topics	O
included	O
programming	B-General_Concept
,	O
graphics	O
,	O
sound	O
and	O
music	O
,	O
teletext	O
,	O
controlling	O
external	O
hardware	O
,	O
and	O
artificial	B-Application
intelligence	I-Application
.	I-Application
</s>
<s>
It	O
developed	O
an	O
ambitious	O
specification	O
for	O
a	O
BBC	B-Device
computer	I-Device
,	O
and	O
discussed	O
the	O
project	O
with	O
several	O
companies	O
including	O
Acorn	O
Computers	O
,	O
Sinclair	O
Research	O
,	O
Newbury	O
Laboratories	O
,	O
Tangerine	O
Computer	O
Systems	O
,	O
and	O
Dragon	O
Data	O
.	O
</s>
<s>
The	O
introduction	O
of	O
a	O
specific	O
microcomputer	B-Architecture
to	O
a	O
more	O
general	O
computer	O
literacy	O
initiative	O
was	O
a	O
topic	O
of	O
controversy	O
,	O
however	O
,	O
with	O
criticism	O
aimed	O
at	O
the	O
BBC	O
for	O
promoting	O
a	O
specific	O
commercial	O
product	O
and	O
for	O
going	O
beyond	O
the	O
"	O
traditional	O
BBC	O
pattern	O
"	O
of	O
promoting	O
existing	O
information	B-Architecture
networks	I-Architecture
of	O
training	O
and	O
education	O
providers	O
.	O
</s>
<s>
Accusations	O
were	O
even	O
levelled	O
at	O
the	O
Department	O
of	O
Industry	O
for	O
making	O
the	O
BBC	O
"	O
an	O
arm	B-Architecture
of	O
Government	O
industrial	O
policy	O
"	O
and	O
using	O
the	O
Computer	O
Literacy	O
Project	O
as	O
a	O
way	O
of	O
"	O
funding	O
industry	O
through	O
the	O
back	O
door	O
"	O
,	O
obscuring	O
public	O
financial	O
support	O
on	O
behalf	O
of	O
a	O
government	O
that	O
was	O
ostensibly	O
opposed	O
to	O
subsidising	O
industry	O
.	O
</s>
<s>
The	O
Acorn	O
team	O
had	O
already	O
been	O
working	O
on	O
a	O
successor	O
to	O
their	O
existing	O
Atom	B-Device
microcomputer	B-Architecture
.	O
</s>
<s>
Known	O
as	O
the	O
Proton	O
,	O
it	O
included	O
better	O
graphics	O
and	O
a	O
faster	O
2MHz	O
MOS	B-General_Concept
Technology	I-General_Concept
6502	I-General_Concept
central	B-General_Concept
processing	I-General_Concept
unit	I-General_Concept
.	O
</s>
<s>
Although	O
BBC	O
expected	O
a	O
computer	O
with	O
the	O
Zilog	B-General_Concept
Z80	I-General_Concept
CPU	B-Device
and	O
CP/M	B-Application
operating	I-Application
system	I-Application
,	O
not	O
the	O
Proton	O
's	O
6502	B-General_Concept
CPU	B-Device
and	O
proprietary	O
operating	B-General_Concept
system	I-General_Concept
,	O
the	O
Proton	O
was	O
the	O
only	O
machine	O
to	O
match	O
the	O
BBC	O
's	O
specification	O
;	O
it	O
also	O
exceeded	O
the	O
specification	O
in	O
nearly	O
every	O
parameter	O
.	O
</s>
<s>
Based	O
on	O
the	O
Proton	O
prototype	O
the	O
BBC	O
signed	O
a	O
contract	O
with	O
Acorn	O
as	O
early	O
as	O
February	O
1981	O
;	O
by	O
June	O
the	O
BBC	B-Device
Micro	I-Device
's	O
specifications	O
and	O
pricing	O
were	O
decided	O
.	O
</s>
<s>
As	O
a	O
concession	O
to	O
the	O
BBC	O
's	O
expectation	O
of	O
"	O
industry	O
standard	O
"	O
compatibility	O
with	O
CP/M	B-Application
,	O
apparently	O
under	O
the	O
direction	O
of	O
John	O
Coll	O
,	O
the	O
Tube	B-Device
interface	I-Device
was	O
incorporated	O
into	O
the	O
design	O
,	O
enabling	O
a	O
Z80	B-General_Concept
second	O
processor	B-Device
to	O
be	O
added	O
.	O
</s>
<s>
An	O
Acorn	O
representative	O
admitted	O
that	O
the	O
BBC	B-Device
Model	I-Device
B	I-Device
would	O
not	O
be	O
competitive	O
throughout	O
the	O
term	O
of	O
the	O
renewed	O
contract	O
and	O
that	O
a	O
successor	O
would	O
emerge	O
.	O
</s>
<s>
The	O
OS	O
ROM	B-Device
v1.0	O
contains	O
the	O
following	O
ASCII	O
credits	O
string	O
(	O
code	O
)	O
:	O
</s>
<s>
(	O
C	O
)	O
1981	O
Acorn	O
Computers	O
Ltd.Thanks	O
are	O
due	O
to	O
the	O
following	O
contributors	O
to	O
the	O
development	O
of	O
the	O
BBC	B-Device
Computer	I-Device
(	O
among	O
others	O
too	O
numerous	O
to	O
mention	O
)	O
:	O
-	O
David	O
Allen	O
,	O
Bob	O
Austin	O
,	O
Ram	B-Architecture
Banerjee	O
,	O
Paul	O
Bond	O
,	O
Allen	O
Boothroyd	O
,	O
Cambridge	O
,	O
Cleartone	O
,	O
John	O
Coll	O
,	O
John	O
Cox	O
,	O
Andy	O
Cripps	O
,	O
Chris	O
Curry	O
,	O
6502	B-General_Concept
designers	O
,	O
Jeremy	O
Dion	O
,	O
Tim	O
Dobson	O
,	O
Joe	O
Dunn	O
,	O
Paul	O
Farrell	O
,	O
Ferranti	O
,	O
Steve	O
Furber	O
,	O
Jon	O
Gibbons	O
,	O
Andrew	O
Gordon	O
,	O
Lawrence	O
Hardwick	O
,	O
Dylan	O
Harris	O
,	O
Hermann	O
Hauser	O
,	O
Hitachi	O
,	O
Andy	O
Hopper	O
,	O
ICL	O
,	O
Martin	O
Jackson	O
,	O
Brian	O
Jones	O
,	O
Chris	O
Jordan	O
,	O
David	O
King	O
,	O
David	O
Kitson	O
,	O
Paul	O
Kriwaczek	O
,	O
Computer	O
Laboratory	O
,	O
Peter	O
Miller	O
,	O
Arthur	O
Norman	O
,	O
Glyn	O
Phillips	O
,	O
Mike	O
Prees	O
,	O
John	O
Radcliffe	O
,	O
Wilberforce	O
Road	O
,	O
Peter	O
Robinson	O
,	O
Richard	O
Russell	O
,	O
Kim	O
Spence-Jones	O
,	O
Graham	O
Tebby	O
,	O
Jon	O
Thackray	O
,	O
Chris	O
Turner	O
,	O
Adrian	O
Warner	O
,	O
Roger	O
Wilson	O
,	O
Alan	O
Wright	O
.	O
</s>
<s>
Additionally	O
,	O
the	O
last	O
bytes	B-Application
of	O
the	O
BASIC	O
ROM	B-Device
(	O
v2	O
and	O
v4	O
)	O
include	O
the	O
word	O
"	O
Roger	O
"	O
,	O
which	O
is	O
a	O
reference	O
to	O
Sophie	O
Wilson	O
whose	O
name	O
at	O
the	O
time	O
was	O
Roger	O
Wilson	O
.	O
</s>
<s>
The	O
machine	O
was	O
released	O
as	O
the	O
BBC	B-Device
Microcomputer	I-Device
on	O
1	O
December	O
1981	O
,	O
although	O
production	O
problems	O
pushed	O
delivery	O
of	O
the	O
majority	O
of	O
the	O
initial	O
run	O
into	O
1982	O
.	O
</s>
<s>
Nicknamed	O
"	O
the	O
Beeb	O
"	O
,	O
it	O
was	O
popular	O
in	O
the	O
UK	O
,	O
especially	O
in	O
the	O
educational	O
market	O
;	O
about	O
80%	O
of	O
British	O
schools	O
had	O
a	O
BBC	B-Device
microcomputer	I-Device
.	O
</s>
<s>
BYTE	B-Application
called	O
the	O
BBC	B-Device
Micro	I-Device
Model	O
B	O
"	O
a	O
no-compromise	O
computer	O
that	O
has	O
many	O
uses	O
beyond	O
self-instruction	O
in	O
computer	O
technology	O
"	O
.	O
</s>
<s>
It	O
called	O
the	O
Tube	B-Device
interface	I-Device
"	O
the	O
most	O
innovative	O
feature	O
"	O
of	O
the	O
computer	O
,	O
and	O
concluded	O
that	O
"	O
although	O
some	O
other	O
British	O
microcomputers	B-Architecture
offer	O
more	O
features	O
for	O
a	O
given	O
price	O
,	O
none	O
of	O
them	O
surpass	O
the	O
BBC	O
...	O
in	O
terms	O
of	O
versatility	O
and	O
expansion	O
capability	O
"	O
.	O
</s>
<s>
As	O
with	O
Sinclair	O
Research	O
's	O
ZX	B-Operating_System
Spectrum	I-Operating_System
and	O
Commodore	O
International	O
's	O
Commodore	O
64	O
,	O
both	O
released	O
the	O
following	O
year	O
,	O
in	O
1982	O
,	O
demand	O
greatly	O
exceeded	O
supply	O
.	O
</s>
<s>
The	O
involvement	O
of	O
the	O
BBC	O
in	O
microcomputing	B-Architecture
also	O
initiated	O
tentative	O
plans	O
by	O
the	O
independent	O
television	O
companies	O
of	O
the	O
ITV	O
network	B-Architecture
to	O
introduce	O
their	O
own	O
initiative	O
and	O
rival	O
computing	O
system	O
,	O
with	O
a	O
CP/M	B-Application
-based	O
system	O
proposed	O
by	O
Transam	O
Computers	O
under	O
consideration	O
for	O
such	O
an	O
initiative	O
by	O
the	O
Independent	O
Television	O
Companies	O
Association	O
at	O
a	O
late	O
1983	O
meeting	O
.	O
</s>
<s>
The	O
proposed	O
machine	O
would	O
have	O
been	O
priced	O
at	O
£399	O
,	O
matching	O
that	O
of	O
the	O
BBC	B-Device
Model	I-Device
B	I-Device
,	O
and	O
was	O
reported	O
as	O
offering	O
64KB	O
of	O
RAM	B-Architecture
,	O
a	O
disc	O
interface	O
,	O
and	O
serial	B-Protocol
and	O
parallel	B-Device
interfaces	I-Device
,	O
itself	O
being	O
a	O
"	O
low-cost	O
development	O
"	O
of	O
an	O
existing	O
machine	O
,	O
the	O
Transam	O
Tuscan	O
,	O
which	O
included	O
dual	O
floppy	B-Device
drives	I-Device
and	O
cost	O
£	O
1,700	O
.	O
</s>
<s>
However	O
,	O
not	O
all	O
ITV	O
franchise	O
holders	O
were	O
equally	O
enthusiastic	O
about	O
scheduling	O
programmes	O
related	O
to	O
microcomputing	B-Architecture
or	O
about	O
pursuing	O
a	O
computer	O
retailing	O
strategy	O
.	O
</s>
<s>
In	O
one	O
deployment	O
in	O
Lowell	O
,	O
Massachusetts	O
valued	O
at	O
$177	O
,	O
000	O
,	O
138	O
BBC	B-Device
Micros	I-Device
were	O
installed	O
in	O
eight	O
of	O
the	O
27	O
schools	O
in	O
the	O
city	O
,	O
with	O
the	O
computer	O
's	O
networking	O
capabilities	O
,	O
educational	O
credentials	O
,	O
and	O
the	O
availability	O
of	O
software	O
with	O
"	O
high	O
education	O
quality	O
"	O
accompanied	O
by	O
"	O
useful	O
lesson	O
plans	O
and	O
workbooks	O
"	O
all	O
given	O
as	O
reasons	O
for	O
selecting	O
Acorn	O
's	O
machine	O
in	O
preference	O
to	O
the	O
competition	O
from	O
IBM	O
,	O
Apple	O
and	O
Commodore	O
.	O
</s>
<s>
Another	O
deployment	O
in	O
Phoenix	O
,	O
Arizona	O
valued	O
at	O
$	O
174,697	O
saw	O
175	O
BBC	B-Device
Micros	I-Device
installed	O
,	O
with	O
the	O
local	O
Acorn	O
dealer	O
predicting	O
sales	O
worth	O
in	O
the	O
following	O
two	O
years	O
,	O
of	O
which	O
around	O
85	O
to	O
90	O
percent	O
would	O
be	O
made	O
into	O
education	O
,	O
the	O
remainder	O
going	O
to	O
the	O
small	O
business	O
market	O
.	O
</s>
<s>
In	O
early	O
1984	O
,	O
Acorn	O
claimed	O
a	O
US	O
network	B-Architecture
of	O
more	O
than	O
1,000	O
dealers	O
.	O
</s>
<s>
In	O
October	O
1984	O
,	O
while	O
preparing	O
a	O
major	O
expansion	O
of	O
its	O
US	O
dealer	O
network	B-Architecture
,	O
Acorn	O
claimed	O
sales	O
of	O
85	O
per	O
cent	O
of	O
the	O
computers	O
in	O
British	O
schools	O
,	O
and	O
delivery	O
of	O
40,000	O
machines	O
per	O
month	O
.	O
</s>
<s>
The	O
New	O
York	O
Times	O
considered	O
the	O
inclusion	O
of	O
local	B-General_Concept
area	I-General_Concept
networking	I-General_Concept
to	O
be	O
of	O
prime	O
importance	O
to	O
teachers	O
.	O
</s>
<s>
The	O
success	O
of	O
the	O
machine	O
in	O
the	O
UK	O
was	O
due	O
largely	O
to	O
its	O
acceptance	O
as	O
an	O
"	O
educational	O
"	O
computer	O
–	O
UK	O
schools	O
used	O
BBC	B-Device
Micros	I-Device
to	O
teach	O
computer	O
literacy	O
,	O
information	O
technology	O
skills	O
.	O
</s>
<s>
Intending	O
to	O
avoid	O
"	O
re-inventing	O
the	O
wheel	O
"	O
,	O
such	O
efforts	O
adopted	O
the	O
BBC	B-Device
Micro	I-Device
in	O
order	O
to	O
take	O
immediate	O
advantage	O
of	O
the	O
extensive	O
range	O
of	O
software	O
already	O
developed	O
under	O
the	O
United	O
Kingdom	O
's	O
own	O
literacy	O
initiative	O
,	O
proposing	O
that	O
software	O
tailored	O
for	O
local	O
requirements	O
would	O
ultimately	O
also	O
be	O
developed	O
.	O
</s>
<s>
A	O
clone	O
of	O
the	O
BBC	B-Device
Micro	I-Device
was	O
produced	O
by	O
Semiconductor	O
Complex	O
Limited	O
and	O
named	O
the	O
SCL	O
Unicorn	O
.	O
</s>
<s>
Another	O
Indian	O
computer	O
manufacturer	O
,	O
Hope	O
Computers	O
Pvt	O
Ltd	O
,	O
made	O
a	O
BBC	B-Device
Micro	I-Device
clone	O
called	O
the	O
Dolphin	O
.	O
</s>
<s>
Unlike	O
the	O
original	O
BBC	B-Device
Micro	I-Device
,	O
the	O
Dolphin	O
featured	O
blue	O
function	B-Application
keys	I-Application
.	O
</s>
<s>
Production	O
agreements	O
were	O
made	O
with	O
both	O
SCL	O
in	O
India	O
and	O
distributor	O
Harry	O
Mazal	O
in	O
Mexico	O
for	O
the	O
assembly	O
of	O
BBC	B-Device
Micro	I-Device
units	O
from	O
kits	O
of	O
parts	O
,	O
leading	O
to	O
full-scale	O
manufacturing	O
,	O
with	O
SCL	O
also	O
planning	O
to	O
fabricate	O
the	O
6502	B-General_Concept
CPU	B-Device
under	O
licence	O
from	O
Rockwell	O
.	O
</s>
<s>
The	O
initial	O
strategy	O
for	O
the	O
BBC	O
's	O
computer	O
literacy	O
endeavour	O
involved	O
the	O
marketing	O
of	O
the	O
"	O
Acorn	O
Proton-based	O
BBC	B-Device
microcomputer	I-Device
for	O
less	O
than	O
£200	O
"	O
.	O
</s>
<s>
Acorn	O
anticipated	O
total	O
sales	O
to	O
be	O
around	O
12,000	O
units	O
,	O
but	O
eventually	O
more	O
than	O
1.5	O
million	O
BBC	B-Device
Micros	I-Device
were	O
sold	O
.	O
</s>
<s>
The	O
cost	O
of	O
the	O
BBC	O
Models	O
was	O
high	O
compared	O
to	O
competitors	O
such	O
as	O
the	O
ZX	B-Operating_System
Spectrum	I-Operating_System
and	O
the	O
Commodore	O
64	O
,	O
and	O
from	O
1983	O
on	O
Acorn	O
attempted	O
to	O
counter	O
this	O
by	O
producing	O
a	O
simplified	O
but	O
largely	O
compatible	O
version	O
intended	O
for	O
home	O
use	O
,	O
complementing	O
the	O
use	O
of	O
the	O
BBC	B-Device
Micro	I-Device
in	O
schools	O
:	O
the	O
32K	O
Acorn	B-Device
Electron	I-Device
.	O
</s>
<s>
A	O
key	O
feature	O
of	O
the	O
BBC	B-Device
Micro	I-Device
's	O
design	O
is	O
the	O
high-performance	O
RAM	B-Architecture
it	O
is	O
equipped	O
with	O
.	O
</s>
<s>
A	O
common	O
design	O
note	O
in	O
6502	B-General_Concept
computers	O
of	O
the	O
era	O
was	O
to	O
run	O
the	O
RAM	B-Architecture
at	O
twice	O
the	O
clock	O
rate	O
as	O
the	O
CPU	B-Device
.	O
</s>
<s>
This	O
allows	O
a	O
separate	O
video	B-General_Concept
display	I-General_Concept
controller	I-General_Concept
to	O
access	O
memory	O
while	O
the	O
CPU	B-Device
is	O
busy	O
processing	O
the	O
data	O
just	O
read	O
.	O
</s>
<s>
In	O
this	O
way	O
,	O
the	O
CPU	B-Device
and	O
graphics	O
driver	O
can	O
share	O
access	O
to	O
RAM	B-Architecture
through	O
careful	O
timing	O
.	O
</s>
<s>
The	O
BBC	O
machine	O
,	O
however	O
,	O
was	O
designed	O
to	O
run	O
at	O
the	O
faster	O
CPU	B-Device
speed	O
,	O
2MHz	O
,	O
double	O
that	O
of	O
these	O
earlier	O
machines	O
.	O
</s>
<s>
In	O
this	O
case	O
,	O
bus	B-Architecture
contention	I-Architecture
is	O
normally	O
an	O
issue	O
,	O
as	O
there	O
is	O
not	O
enough	O
time	O
for	O
the	O
CPU	B-Device
to	O
access	O
the	O
memory	O
during	O
the	O
period	O
when	O
the	O
video	O
hardware	O
is	O
idle	O
.	O
</s>
<s>
Some	O
machines	O
of	O
the	O
era	O
accept	O
the	O
inherent	O
performance	O
hit	O
,	O
as	O
is	O
the	O
case	O
for	O
the	O
Amstrad	B-Device
CPC	I-Device
,	O
Atari	B-Device
8-bit	I-Device
family	I-Device
,	O
and	O
to	O
a	O
lesser	O
extent	O
the	O
ZX	B-Operating_System
Spectrum	I-Operating_System
.	O
</s>
<s>
Others	O
,	O
like	O
the	O
MSX	B-Operating_System
systems	O
,	O
use	O
entirely	O
separate	O
pools	O
of	O
memory	O
for	O
the	O
CPU	B-Device
and	O
video	O
,	O
slowing	O
access	O
between	O
the	O
two	O
.	O
</s>
<s>
Furber	O
believed	O
that	O
the	O
Acorn	O
design	O
should	O
have	O
a	O
flat	B-General_Concept
memory	I-General_Concept
model	I-General_Concept
and	O
allow	O
the	O
CPU	B-Device
and	O
video	O
system	O
to	O
access	O
the	O
bus	O
without	O
interfering	O
with	O
each	O
other	O
.	O
</s>
<s>
To	O
do	O
so	O
,	O
the	O
RAM	B-Architecture
has	O
to	O
allow	O
four	O
million	O
access	O
cycles	O
per	O
second	O
.	O
</s>
<s>
The	O
National	O
Semiconductor	O
81LS95	O
multiplexer	B-Protocol
is	O
needed	O
for	O
the	O
high	O
memory	O
speed	O
.	O
</s>
<s>
And	O
a	O
million	O
and	O
a	O
half	O
BBC	B-Device
Micros	I-Device
later	O
it	O
was	O
still	O
working	O
and	O
I	O
still	O
did	O
n't	O
know	O
why	O
"	O
.	O
</s>
<s>
Another	O
mystery	O
was	O
the	O
6502	B-General_Concept
's	O
data	B-General_Concept
bus	I-General_Concept
.	O
</s>
<s>
The	O
prototype	O
BBC	B-Device
Micro	I-Device
exceeded	O
the	O
CPU	B-Device
's	O
specifications	O
,	O
causing	O
it	O
to	O
fail	O
.	O
</s>
<s>
Acorn	O
put	O
a	O
resistor	O
pack	O
across	O
the	O
data	B-General_Concept
bus	I-General_Concept
,	O
which	O
Furber	O
described	O
as	O
the	O
engineer	O
's	O
finger	O
 '	O
and	O
again	O
,	O
we	O
have	O
no	O
idea	O
why	O
it	O
's	O
necessary	O
,	O
and	O
a	O
million	O
and	O
a	O
half	O
machines	O
later	O
it	O
's	O
still	O
working	O
,	O
so	O
nobody	O
asked	O
any	O
questions	O
"	O
.	O
</s>
<s>
The	O
Model	O
A	O
shipped	O
with	O
16KB	O
of	O
user	O
RAM	B-Architecture
,	O
while	O
the	O
Model	O
B	O
had	O
32KB	O
.	O
</s>
<s>
The	O
machines	O
includes	O
three	O
video	O
ports	O
,	O
one	O
with	O
an	O
RF	O
modulator	O
sending	O
out	O
a	O
signal	O
in	O
the	O
UHF	O
band	O
,	O
another	O
sending	O
composite	O
video	O
suitable	O
for	O
connection	O
to	O
computer	B-Device
monitors	I-Device
,	O
and	O
a	O
separate	O
RGB	O
video	O
port	O
.	O
</s>
<s>
The	O
separate	O
RGB	O
video	O
out	O
socket	O
was	O
an	O
engineering	O
requirement	O
from	O
the	O
BBC	O
to	O
allow	O
the	O
machine	O
to	O
directly	O
output	O
a	O
broadcast	O
quality	O
signal	O
for	O
use	O
within	O
television	O
programming	B-General_Concept
;	O
it	O
is	O
used	O
on	O
episodes	O
of	O
The	O
Computer	O
Programme	O
and	O
Making	O
the	O
Most	O
of	O
the	O
Micro	O
.	O
</s>
<s>
The	O
computer	O
includes	O
several	O
input/output	B-General_Concept
interfaces	O
:	O
serial	B-Protocol
and	O
parallel	B-Device
printer	I-Device
ports	I-Device
,	O
an	O
8-bit	O
general	O
purpose	O
digital	O
I/O	B-General_Concept
port	O
,	O
a	O
port	O
offering	O
four	O
analogue	O
inputs	O
,	O
a	O
light	B-Device
pen	I-Device
input	O
,	O
and	O
an	O
expansion	O
connector	O
(	O
the	O
"	O
1	O
MHz	O
bus	O
"	O
)	O
that	O
enables	O
other	O
hardware	O
to	O
be	O
connected	O
.	O
</s>
<s>
An	O
Econet	B-Device
network	B-Architecture
interface	O
and	O
a	O
disk	B-Device
drive	I-Device
interface	O
were	O
available	O
as	O
options	O
.	O
</s>
<s>
All	O
motherboards	O
have	O
space	O
for	O
the	O
electronic	O
components	O
,	O
but	O
Econet	B-Device
is	O
rarely	O
installed	O
.	O
</s>
<s>
Additionally	O
,	O
an	O
Acorn	O
proprietary	O
interface	O
named	O
the	O
"	O
Tube	B-Device
"	O
allows	O
a	O
second	O
processor	B-Device
to	O
be	O
added	O
.	O
</s>
<s>
Three	O
models	O
of	O
second	O
processor	B-Device
were	O
offered	O
by	O
Acorn	O
,	O
based	O
on	O
the	O
6502	B-General_Concept
,	O
Z80	B-General_Concept
and	O
32016	B-Device
CPUs	B-Device
.	O
</s>
<s>
The	O
Tube	B-Device
is	O
used	O
for	O
third-party	O
add-ons	O
,	O
including	O
a	O
Z80	B-General_Concept
board	O
and	O
hard	B-Device
disk	I-Device
drive	I-Device
from	O
Torch	O
that	O
allows	O
the	O
BBC	O
machine	O
to	O
run	O
CP/M	B-Application
programs	O
.	O
</s>
<s>
Separate	O
pages	O
,	O
each	O
with	O
a	O
codename	O
,	O
are	O
used	O
to	O
control	O
the	O
access	O
to	O
the	O
I/O	B-General_Concept
:	O
</s>
<s>
The	O
Tube	B-Device
interface	I-Device
allowed	O
Acorn	O
to	O
use	O
BBC	B-Device
Micros	I-Device
with	O
ARM	B-Architecture
CPUs	B-Device
as	O
software	O
development	O
machines	O
when	O
creating	O
the	O
Acorn	B-Device
Archimedes	I-Device
.	O
</s>
<s>
This	O
resulted	O
in	O
the	O
ARM	B-Architecture
development	O
kit	O
for	O
the	O
BBC	B-Device
Micro	I-Device
in	O
1986	O
,	O
priced	O
at	O
around	O
£4000	O
.	O
</s>
<s>
From	O
2006	O
,	O
a	O
kit	O
with	O
an	O
ARM7TDMI	O
CPU	B-Device
running	O
at	O
64MHz	O
,	O
with	O
as	O
much	O
as	O
64MB	O
of	O
RAM	B-Architecture
,	O
was	O
released	O
for	O
the	O
BBC	B-Device
Micro	I-Device
and	O
Master	O
,	O
using	O
the	O
Tube	B-Device
interface	I-Device
to	O
upgrade	O
the	O
8-bit	O
micros	O
into	O
32-bit	O
RISC	B-Architecture
machines	O
.	O
</s>
<s>
Among	O
the	O
software	O
that	O
operated	O
on	O
the	O
Tube	B-Device
are	O
an	O
enhanced	O
version	O
of	O
the	O
Elite	B-Application
video	O
game	O
and	O
a	O
computer-aided	B-Application
design	I-Application
system	O
that	O
requires	O
a	O
second	O
6502	B-General_Concept
CPU	B-Device
and	O
a	O
3-dimensional	O
joystick	B-Device
named	O
a	O
"	O
Bitstik	O
"	O
.	O
</s>
<s>
Users	O
wishing	O
to	O
operate	O
Model	O
B	O
software	O
need	O
to	O
add	O
the	O
extra	O
RAM	B-Architecture
and	O
the	O
user/printer	O
MOS	B-Device
Technology	I-Device
6522	I-Device
VIA	O
(	O
which	O
many	O
games	O
use	O
for	O
timers	O
)	O
and	O
snip	O
a	O
link	O
,	O
a	O
task	O
that	O
can	O
be	O
achieved	O
without	O
soldering	O
.	O
</s>
<s>
Variations	O
in	O
the	O
Acorn	B-Operating_System
OS	I-Operating_System
exist	O
as	O
a	O
result	O
of	O
home-made	O
projects	O
and	O
modified	O
machines	O
can	O
still	O
be	O
bought	O
on	O
internet	O
auction	O
sites	O
such	O
as	O
eBay	B-Application
as	O
of	O
2011	O
.	O
</s>
<s>
The	O
BBC	B-Device
Model	I-Device
A	I-Device
was	O
phased	O
out	O
of	O
production	O
with	O
the	O
introduction	O
of	O
the	O
Acorn	B-Device
Electron	I-Device
,	O
with	O
chairman	O
Chris	O
Curry	O
stating	O
at	O
the	O
time	O
that	O
Acorn	O
"	O
would	O
no	O
longer	O
promote	O
it	O
"	O
(	O
the	O
Model	O
A	O
)	O
.	O
</s>
<s>
Early	O
BBC	B-Device
Micros	I-Device
use	O
linear	O
power	O
supplies	O
at	O
the	O
insistence	O
of	O
the	O
BBC	O
which	O
,	O
as	O
a	O
broadcaster	O
,	O
was	O
cautious	O
about	O
electromagnetic	O
interference	O
.	O
</s>
<s>
There	O
are	O
five	O
developments	O
of	O
the	O
main	O
BBC	B-Device
Micro	I-Device
circuit	O
board	O
that	O
addressed	O
various	O
issues	O
through	O
the	O
models	O
production	O
,	O
from	O
'	O
Issue	O
1	O
 '	O
through	O
to	O
'	O
Issue	O
7	O
 '	O
with	O
variants	O
5	O
and	O
6	O
not	O
being	O
released	O
.	O
</s>
<s>
The	O
1985	O
'	O
BBC	B-Device
Microcomputer	I-Device
Service	O
Manual	O
 '	O
from	O
Acorn	O
documents	O
the	O
details	O
of	O
the	O
technical	O
changes	O
.	O
</s>
<s>
Per	O
Watford	O
Electronics	O
comments	O
in	O
their	O
'	O
32K	O
Ram	B-Architecture
Board	O
Manual	O
 '	O
:	O
</s>
<s>
Two	O
export	O
models	O
were	O
developed	O
:	O
one	O
for	O
the	O
US	O
,	O
with	O
Econet	B-Device
and	O
speech	O
hardware	O
as	O
standard	O
;	O
the	O
other	O
for	O
West	O
Germany	O
.	O
</s>
<s>
From	O
June	O
1983	O
the	O
name	O
was	O
always	O
spelled	O
out	O
completely	O
–	O
"	O
British	B-Device
Broadcasting	I-Device
Corporation	I-Device
Microcomputer	I-Device
System	I-Device
"	O
–	O
to	O
avoid	O
confusion	O
with	O
Brown	O
,	O
Boveri	O
&	O
Cie	O
in	O
international	O
markets	O
,	O
after	O
warnings	O
from	O
the	O
Swiss	O
multinational	O
not	O
to	O
market	O
the	O
computer	O
with	O
the	O
BBC	O
label	O
in	O
West	O
Germany	O
,	O
thus	O
forcing	O
Acorn	O
to	O
relabel	O
"	O
hundreds	O
of	O
machines	O
"	O
to	O
comply	O
with	O
these	O
demands	O
.	O
</s>
<s>
US	O
models	O
include	O
the	O
BASIC	O
III	O
ROM	B-Device
chip	I-Device
,	O
modified	O
to	O
accept	O
the	O
American	O
spelling	O
of	O
COLOR	O
,	O
but	O
the	O
height	O
of	O
the	O
graphics	O
display	O
was	O
reduced	O
to	O
200	O
scan	B-Algorithm
lines	I-Algorithm
to	O
suit	O
NTSC	O
TVs	O
,	O
severely	O
affecting	O
applications	O
written	O
for	O
British	O
computers	O
.	O
</s>
<s>
In	O
October	O
1984	O
,	O
the	O
Acorn	B-Device
Business	I-Device
Computer	I-Device
(	O
ABC	O
)	O
/Acorn	O
Cambridge	O
Workstation	O
range	O
of	O
machines	O
was	O
announced	O
,	O
based	O
primarily	O
on	O
BBC	O
hardware	O
.	O
</s>
<s>
In	O
mid-1985	O
,	O
Acorn	O
introduced	O
the	O
Model	O
B+	O
which	O
increased	O
the	O
total	O
RAM	B-Architecture
to	O
64KB	O
.	O
</s>
<s>
The	O
extra	O
RAM	B-Architecture
in	O
the	O
Model	O
B+	O
is	O
assigned	O
as	O
two	O
blocks	O
,	O
a	O
block	O
of	O
20KB	O
dedicated	O
solely	O
for	O
screen	O
display	O
(	O
so-called	O
shadow	B-General_Concept
RAM	I-General_Concept
)	O
and	O
a	O
block	O
of	O
12KB	O
of	O
special	O
sideways	B-General_Concept
RAM	I-General_Concept
.	O
</s>
<s>
The	O
B+128	O
,	O
introduced	O
towards	O
the	O
end	O
of	O
1985	O
,	O
comes	O
with	O
an	O
additional	O
64KB	O
(	O
4	O
×	O
16KB	O
sideways	B-General_Concept
RAM	I-General_Concept
banks	O
)	O
to	O
give	O
a	O
total	O
RAM	B-Architecture
of	O
128KB	O
.	O
</s>
<s>
The	O
B+	O
is	O
incapable	O
of	O
operating	O
some	O
original	O
BBC	B-Device
B	I-Device
programs	O
and	O
games	O
,	O
such	O
as	O
the	O
very	O
popular	O
Castle	B-Application
Quest	I-Application
.	O
</s>
<s>
A	O
particular	O
problem	O
is	O
the	O
replacement	O
of	O
the	O
Intel	O
8271	O
floppy-disk	B-Device
controller	I-Device
with	O
the	O
Western	B-Device
Digital	I-Device
1770	I-Device
:	O
not	O
only	O
was	O
the	O
new	O
controller	O
mapped	O
to	O
different	O
addresses	O
,	O
it	O
is	O
fundamentally	O
incompatible	O
and	O
the	O
8271	O
emulators	B-Application
that	O
existed	O
were	O
necessarily	O
imperfect	O
for	O
all	O
but	O
basic	O
operation	O
.	O
</s>
<s>
Software	O
that	O
use	O
copy	B-Application
protection	I-Application
techniques	O
involving	O
direct	O
access	O
to	O
the	O
controller	O
do	O
not	O
operate	O
on	O
the	O
new	O
system	O
.	O
</s>
<s>
Acorn	O
attempted	O
to	O
alleviate	O
this	O
,	O
starting	O
with	O
version	O
2.20	O
of	O
the	O
1770	O
DFS	B-Application
,	O
via	O
an	O
8271-backward	O
-	O
compatible	O
++	O
option	O
.	O
</s>
<s>
There	O
is	O
also	O
a	O
long-running	O
problem	O
late	O
in	O
the	O
B/B	O
+'s	O
commercial	O
life	O
infamous	O
amongst	O
B+	O
owners	O
,	O
when	O
Superior	B-Device
Software	I-Device
released	O
Repton	B-Application
Infinity	I-Application
,	O
which	O
did	O
not	O
run	O
on	O
the	O
B+	O
.	O
</s>
<s>
During	O
1986	O
,	O
Acorn	O
followed	O
up	O
with	O
the	O
BBC	B-Device
Master	I-Device
,	O
which	O
offers	O
memory	O
sizes	O
from	O
128KB	O
and	O
many	O
other	O
refinements	O
which	O
improves	O
on	O
the	O
1981	O
original	O
.	O
</s>
<s>
It	O
has	O
essentially	O
the	O
same	O
6502-based	O
BBC	O
architecture	O
,	O
with	O
many	O
of	O
the	O
upgrades	O
that	O
the	O
original	O
design	O
intentionally	O
makes	O
possible	O
(	O
extra	O
ROM	B-Device
software	O
,	O
extra	O
paged	O
RAM	B-Architecture
,	O
second	O
processors	O
)	O
now	O
included	O
on	O
the	O
circuit	O
board	O
as	O
internal	O
plug-in	O
modules	O
.	O
</s>
<s>
The	O
BBC	B-Device
Micro	I-Device
platform	O
amassed	O
a	O
large	O
software	O
base	O
of	O
both	O
games	O
and	O
educational	O
programs	O
for	O
its	O
two	O
main	O
uses	O
as	O
a	O
home	O
and	O
educational	O
computer	O
.	O
</s>
<s>
Notable	O
examples	O
of	O
each	O
include	O
the	O
original	O
release	O
of	O
Elite	B-Application
and	O
Granny	B-Application
's	I-Application
Garden	I-Application
.	O
</s>
<s>
Programming	B-General_Concept
languages	O
and	O
some	O
applications	O
were	O
supplied	O
on	O
ROM	B-Device
chips	I-Device
to	O
be	O
installed	O
on	O
the	O
motherboard	O
.	O
</s>
<s>
These	O
load	O
instantly	O
and	O
leave	O
the	O
RAM	B-Architecture
free	O
for	O
programs	O
or	O
documents	O
.	O
</s>
<s>
Although	O
appropriate	O
content	O
was	O
little-supported	O
by	O
television	O
broadcasters	O
,	O
telesoftware	O
could	O
be	O
downloaded	O
via	O
the	O
optional	O
Teletext	B-Device
Adapter	I-Device
and	O
the	O
third-party	O
teletext	O
adaptors	O
that	O
emerged	O
.	O
</s>
<s>
The	O
built-in	O
operating	B-General_Concept
system	I-General_Concept
,	O
Acorn	B-Operating_System
MOS	I-Operating_System
,	O
provides	O
an	O
extensive	O
API	B-General_Concept
to	O
interface	O
with	O
all	O
standard	O
peripherals	O
,	O
ROM-based	O
software	O
,	O
and	O
the	O
screen	O
.	O
</s>
<s>
Features	O
specific	O
to	O
some	O
versions	O
of	O
BASIC	O
,	O
like	O
vector	O
graphics	O
,	O
keyboard	B-Device
macros	O
,	O
cursor-based	O
editing	O
,	O
sound	O
queues	O
,	O
and	O
envelopes	O
,	O
are	O
in	O
the	O
MOS	B-Operating_System
ROM	B-Device
and	O
made	O
available	O
to	O
any	O
application	O
.	O
</s>
<s>
BBC	B-Language
BASIC	I-Language
itself	O
,	O
being	O
in	O
a	O
separate	O
ROM	B-Device
,	O
can	O
be	O
replaced	O
with	O
another	O
language	O
.	O
</s>
<s>
BASIC	O
,	O
other	O
languages	O
,	O
and	O
utility	O
ROM	B-Device
chips	I-Device
reside	O
in	O
any	O
of	O
four	O
16KB	O
paged	O
ROM	B-Device
sockets	O
,	O
with	O
OS	O
support	O
for	O
sixteen	O
sockets	O
via	O
expansion	O
hardware	O
.	O
</s>
<s>
The	O
five	O
(	O
total	O
)	O
sockets	O
are	O
located	O
partially	O
obscured	O
under	O
the	O
keyboard	B-Device
,	O
with	O
the	O
leftmost	O
socket	O
hard-wired	O
for	O
the	O
OS	O
.	O
</s>
<s>
The	O
intended	O
purpose	O
for	O
the	O
perforated	O
panel	O
on	O
the	O
left	O
of	O
the	O
keyboard	B-Device
was	O
for	O
a	O
Serial	B-Protocol
ROM	B-Device
or	O
Speech	O
ROM	B-Device
.	O
</s>
<s>
The	O
paged	O
ROM	B-Device
system	O
is	O
essentially	O
modular	O
.	O
</s>
<s>
A	O
language-independent	O
system	O
of	O
star	O
commands	O
,	O
prefixed	O
with	O
an	O
asterisk	O
,	O
provides	O
the	O
ability	O
to	O
select	O
a	O
language	O
(	O
for	O
example	O
*	O
BASIC	O
,	O
*	O
PASCAL	B-Application
)	O
,	O
a	O
filing	O
system	O
( *	O
TAPE	O
,	O
*	O
DISC	O
)	O
,	O
change	O
settings	O
( *	O
FX	O
,	O
*	O
OPT	O
)	O
,	O
or	O
carry	O
out	O
ROM-supplied	O
tasks	O
( *	O
COPY	O
,	O
*	O
BACKUP	O
)	O
from	O
the	O
command	O
line	O
.	O
</s>
<s>
The	O
MOS	B-Operating_System
recognises	O
certain	O
built-in	O
commands	O
,	O
and	O
polls	O
the	O
paged	O
ROMs	O
in	O
descending	O
order	O
for	O
service	O
otherwise	O
;	O
if	O
none	O
of	O
them	O
claims	O
the	O
command	O
then	O
the	O
OS	O
returns	O
a	O
Bad	O
command	O
error	O
.	O
</s>
<s>
Suitable	O
ROM	B-Device
(	O
or	O
EPROM	O
)	O
images	O
could	O
be	O
written	O
and	O
provide	O
functions	O
without	O
requiring	O
RAM	B-Architecture
for	O
the	O
code	O
itself	O
.	O
</s>
<s>
Not	O
all	O
ROMs	O
offer	O
star	O
commands	O
(	O
ROMs	O
containing	O
data	O
files	O
,	O
for	O
instance	O
)	O
,	O
but	O
any	O
ROM	B-Device
can	O
"	O
hook	O
"	O
into	O
vectors	O
to	O
enhance	O
the	O
system	O
's	O
functionality	O
.	O
</s>
<s>
Often	O
the	O
ROM	B-Device
is	O
a	O
device	B-Application
driver	I-Application
for	O
mass	B-Device
storage	I-Device
combined	O
with	O
a	O
filing	O
system	O
,	O
starting	O
with	O
Acorn	O
's	O
1982	O
Disc	B-Application
Filing	I-Application
System	I-Application
whose	O
API	B-General_Concept
became	O
the	O
de	O
facto	O
standard	O
for	O
floppy-disc	O
access	O
.	O
</s>
<s>
The	O
Acorn	O
Graphics	O
Extension	O
ROM	B-Device
(	O
GXR	O
)	O
expands	O
the	O
VDU	O
routines	O
to	O
draw	O
geometric	O
shapes	O
,	O
flood	O
fills	O
,	O
and	O
sprites	O
.	O
</s>
<s>
During	O
1985	O
Micro	O
Power	O
designed	O
and	O
marketed	O
a	O
Basic	O
Extension	O
ROM	B-Device
,	O
introducing	O
statements	O
such	O
as	O
WHILE	O
,	O
ENDWHILE	O
,	O
CASE	O
,	O
WHEN	O
,	O
OTHERWISE	O
,	O
and	O
ENDCASE	O
,	O
as	O
well	O
as	O
direct	O
mode	O
commands	O
including	O
VERIFY	O
.	O
</s>
<s>
Acorn	O
strongly	O
discouraged	O
programmers	O
from	O
directly	O
accessing	O
the	O
system	O
variables	O
and	O
hardware	O
,	O
favouring	O
official	O
system	B-Operating_System
calls	I-Operating_System
.	O
</s>
<s>
This	O
was	O
ostensibly	O
to	O
make	O
sure	O
programs	O
keep	O
working	O
when	O
migrated	O
to	O
coprocessors	O
that	O
utilise	O
the	O
Tube	B-Device
interface	I-Device
,	O
but	O
it	O
also	O
makes	O
BBC	B-Device
Micro	I-Device
software	O
more	O
portable	O
across	O
the	O
Acorn	O
range	O
.	O
</s>
<s>
Whereas	O
untrappable	O
PEEKs	B-Language
and	I-Language
POKEs	I-Language
are	O
used	O
by	O
other	O
computers	O
to	O
reach	O
the	O
system	O
elements	O
,	O
programs	O
in	O
either	O
machine	O
code	O
or	O
BBC	B-Language
BASIC	I-Language
instead	O
pass	O
parameters	O
to	O
an	O
operating	B-General_Concept
system	I-General_Concept
routine	O
.	O
</s>
<s>
In	O
this	O
way	O
the	O
6502	B-General_Concept
can	O
translate	O
the	O
request	O
for	O
the	O
local	O
machine	O
or	O
send	O
it	O
across	O
the	O
Tube	B-Device
interface	I-Device
,	O
as	O
direct	O
access	O
is	O
impossible	O
from	O
the	O
coprocessor	O
.	O
</s>
<s>
Published	O
programs	O
largely	O
conform	O
to	O
the	O
API	B-General_Concept
except	O
for	O
games	O
,	O
which	O
routinely	O
engage	O
with	O
the	O
hardware	O
for	O
greater	O
speed	O
,	O
and	O
require	O
a	O
particular	O
Acorn	O
model	O
.	O
</s>
<s>
Many	O
schools	O
and	O
universities	O
employed	O
the	O
machines	O
in	O
Econet	B-Device
networks	O
,	O
and	O
so	O
networked	O
multiplayer	O
games	O
were	O
possible	O
.	O
</s>
<s>
A	O
relatively	O
late	O
but	O
well	O
documented	O
example	O
can	O
be	O
found	O
in	O
a	O
dissertation	O
based	O
on	O
a	O
ringed	O
RS-423	O
interconnect	B-General_Concept
.	O
</s>
<s>
The	O
built-in	O
ROM-resident	O
BBC	B-Language
BASIC	I-Language
programming	I-Language
language	I-Language
interpreter	B-Application
realised	O
the	O
system	O
's	O
educational	O
emphasis	O
and	O
was	O
key	O
to	O
its	O
success	O
;	O
it	O
is	O
the	O
most	O
comprehensive	O
BASIC	O
compared	O
to	O
other	O
contemporary	O
implementations	O
,	O
and	O
runs	O
very	O
efficiently	O
.	O
</s>
<s>
Advanced	O
programs	O
can	O
be	O
written	O
without	O
resorting	O
to	O
non-structured	B-Application
programming	I-Application
or	O
machine	O
code	O
.	O
</s>
<s>
Should	O
one	O
want	O
or	O
need	O
to	O
do	O
some	O
assembly	O
programming	B-General_Concept
,	O
BBC	B-Language
BASIC	I-Language
has	O
a	O
built-in	O
assembler	O
that	O
allows	O
a	O
mixture	O
of	O
BASIC	O
and	O
assembler	O
for	O
whatever	O
processor	B-Device
BASIC	O
was	O
operating	O
on	O
.	O
</s>
<s>
When	O
the	O
BBC	B-Device
Micro	I-Device
was	O
released	O
,	O
many	O
competing	O
home	O
computers	O
used	O
Microsoft	B-Language
BASIC	I-Language
,	O
or	O
variants	O
typically	O
designed	O
to	O
resemble	O
it	O
.	O
</s>
<s>
Compared	O
to	O
Microsoft	B-Language
BASIC	I-Language
,	O
BBC	B-Language
BASIC	I-Language
features	O
IF	O
...	O
THEN	O
ELSE	O
...	O
,	O
REPEAT	O
...	O
UNTIL	O
,	O
and	O
named	O
procedures	O
and	O
functions	O
,	O
but	O
retains	O
GOTO	B-Application
and	O
GOSUB	B-Device
for	O
compatibility	O
.	O
</s>
<s>
It	O
also	O
supports	O
high-resolution	O
graphics	O
,	O
four-channel	O
sound	O
,	O
pointer-based	O
memory	O
access	O
(	O
borrowed	O
from	O
BCPL	B-Language
)	O
,	O
and	O
rudimentary	O
macro	O
assembly	O
.	O
</s>
<s>
Acorn	O
had	O
made	O
a	O
point	O
of	O
not	O
just	O
supporting	O
BBC	B-Language
Basic	I-Language
but	O
also	O
supporting	O
a	O
number	O
of	O
contemporary	O
languages	O
,	O
some	O
of	O
which	O
were	O
supplied	O
as	O
ROM	B-Device
chips	I-Device
to	O
fit	O
the	O
spare	O
sideways	O
ROM	B-Device
sockets	O
on	O
the	O
motherboard	O
.	O
</s>
<s>
Other	O
languages	O
were	O
supplied	O
on	O
tape	O
or	O
disk	B-Device
.	O
</s>
<s>
Programming	B-General_Concept
languages	O
from	O
Acornsoft	O
included	O
the	O
following	O
:	O
</s>
<s>
Many	O
of	O
these	O
languages	O
were	O
also	O
provided	O
under	O
the	O
Panos	B-Operating_System
environment	O
for	O
the	O
32016	B-Device
Second	O
Processor	B-Device
.	O
</s>
<s>
As	O
the	O
Z80	B-General_Concept
Second	O
Processor	B-Device
provided	O
a	O
CP/M	B-Application
environment	O
,	O
languages	O
available	O
for	O
CP/M	B-Application
were	O
supportable	O
via	O
this	O
route	O
.	O
</s>
<s>
For	O
example	O
,	O
Turbo	B-Application
Pascal	I-Application
was	O
regarded	O
in	O
one	O
instance	O
as	O
"	O
by	O
far	O
the	O
best	O
version	O
of	O
Pascal	B-Application
"	O
for	O
a	O
BBC	B-Device
Micro	I-Device
with	O
Z80	B-General_Concept
second	O
processor	B-Device
.	O
</s>
<s>
DOS-based	O
language	O
implementations	O
such	O
as	O
Turbo	B-Application
C	I-Application
and	O
Turbo	B-Application
Pascal	I-Application
could	O
also	O
be	O
run	O
by	O
computers	O
expanded	O
with	O
the	O
Master	O
512	O
board	O
,	O
this	O
being	O
fitted	O
to	O
BBC	B-Device
Micro	I-Device
machines	O
using	O
a	O
Universal	O
Second	O
Processor	B-Device
unit	O
.	O
</s>
<s>
Torch	O
Computers	O
 '	O
Z80	B-General_Concept
expansions	O
supported	O
the	O
UCSD	B-Language
p-System	I-Language
,	O
and	O
the	O
Torch	O
Unicorn	O
expansion	O
provided	O
a	O
Unix	O
environment	O
that	O
featured	O
a	O
C	O
compiler	O
and	O
other	O
utilities	O
,	O
with	O
Pascal	B-Application
and	O
Fortran	O
77	O
implementations	O
also	O
advertised	O
.	O
</s>
<s>
Acornsoft	O
C	O
did	O
not	O
run	O
on	O
the	O
original	O
BBC	B-Device
Micro	I-Device
models	O
,	O
requiring	O
the	O
extra	O
resources	O
provided	O
by	O
the	O
B+	O
and	O
Master	O
series	O
machines	O
.	O
</s>
<s>
Both	O
of	O
these	O
implementations	O
provided	O
compilers	O
producing	O
interpreted	O
"	O
p-code	O
"	O
as	O
opposed	O
to	O
machine	O
code	O
,	O
similar	O
to	O
Acornsoft	O
's	O
ISO	O
Pascal	B-Application
and	O
BCPL	B-Language
compilers	O
.	O
</s>
<s>
A	O
Small-C	B-Language
implementation	O
was	O
also	O
made	O
available	O
by	O
Mijas	O
.	O
</s>
<s>
For	O
a	O
BBC	B-Device
Micro	I-Device
without	O
a	O
second	O
processor	B-Device
,	O
Acornsoft	O
's	O
ISO	O
Pascal	B-Application
primarily	O
saw	O
competition	O
from	O
Oxford	O
Pascal	B-Application
.	O
</s>
<s>
A	O
Forth-based	O
Pascal	B-Application
implementation	O
from	O
HCCS	O
known	O
as	O
Pascal	B-Application
T	O
was	O
regarded	O
as	O
being	O
"	O
intended	O
primarily	O
for	O
learning	O
Pascal	B-Application
,	O
rather	O
than	O
using	O
it	O
seriously	O
"	O
,	O
putting	O
it	O
in	O
the	O
same	O
category	O
as	O
Acornsoft	O
's	O
S-Pascal	O
,	O
described	O
as	O
"	O
a	O
simple	O
subset	O
of	O
Pascal	B-Application
for	O
teaching	O
the	O
language	O
and	O
structured	O
programming	B-General_Concept
"	O
.	O
</s>
<s>
As	O
a	O
computer	O
aimed	O
at	O
the	O
education	O
market	O
,	O
the	O
BBC	B-Device
Micro	I-Device
was	O
supported	O
by	O
several	O
implementations	O
of	O
Logo	B-Device
:	O
Acornsoft	O
Logo	B-Device
competing	O
with	O
Logo	B-Device
products	O
from	O
Logotron	O
,	O
LSL	O
,	O
and	O
the	O
Open	O
University	O
.	O
</s>
<s>
These	O
products	O
provided	O
either	O
one	O
or	O
two	O
16KB	O
ROM	B-Device
chips	I-Device
for	O
fitting	O
inside	O
the	O
machine	O
,	O
although	O
the	O
Open	O
University	O
's	O
Open	O
Logo	B-Device
provided	O
a	O
second	O
processor	B-Device
implementation	O
that	O
was	O
loaded	O
from	O
disc	O
.	O
</s>
<s>
Acornsoft	O
's	O
Logo	B-Device
was	O
itself	O
written	O
in	O
the	O
BCPL	B-Language
language	I-Language
whereas	O
other	O
implementations	O
had	O
been	O
assembled	O
to	O
machine	O
code	O
.	O
</s>
<s>
Compatibility	O
with	O
Logo	B-Device
dialects	O
and	O
standards	O
varied	O
,	O
with	O
Logotron	O
Logo	B-Device
claiming	O
a	O
level	O
of	O
adherence	O
to	O
the	O
broader	O
Logo	B-Language
Computer	I-Language
Systems	I-Language
Inc	I-Language
.	I-Language
(	O
LCSI	B-Language
)	O
industry	O
standard	O
,	O
and	O
the	O
level	O
of	O
provided	O
functionality	O
differed	O
between	O
the	O
BBC	B-Device
Micro	I-Device
implementations	O
,	O
with	O
Acornsoft	O
Logo	B-Device
providing	O
the	O
most	O
comprehensive	O
set	O
of	O
primitives	O
in	O
many	O
areas	O
.	O
</s>
<s>
Support	O
for	O
various	O
peripherals	O
and	O
accessories	O
was	O
advertised	O
,	O
floor	O
turtles	O
having	O
particular	O
significance	O
,	O
but	O
hardware	O
extensions	O
offering	O
sprite	O
capabilities	O
were	O
also	O
developed	O
for	O
use	O
with	O
certain	O
implementations	O
,	O
notably	O
Logotron	O
Logo	B-Device
.	O
</s>
<s>
Logotron	O
Logo	B-Device
was	O
eventually	O
judged	O
to	O
be	O
the	O
most	O
popular	O
product	O
and	O
was	O
bundled	O
with	O
the	O
Master	O
Compact	O
by	O
Acorn	O
.	O
</s>
<s>
In	O
line	O
with	O
its	O
ethos	O
of	O
expandability	O
Acorn	O
produced	O
its	O
own	O
range	O
of	O
peripherals	O
for	O
the	O
BBC	B-Device
Micro	I-Device
,	O
including	O
:	O
</s>
<s>
For	O
example	O
,	O
companies	O
such	O
as	O
Torch	O
Computers	O
and	O
Cambridge	O
Microprocessor	O
Systems	O
offered	O
second	O
processor	B-Device
solutions	O
for	O
the	O
BBC	B-Device
Micro	I-Device
.	O
</s>
<s>
Acorn	O
produced	O
their	O
own	O
32-bit	O
Reduced	B-Architecture
Instruction	I-Architecture
Set	I-Architecture
Computing	I-Architecture
(	O
RISC	B-Architecture
)	O
CPU	B-Device
during	O
1985	O
,	O
the	O
ARM1	O
.	O
</s>
<s>
Furber	O
composed	O
a	O
reference	O
model	O
of	O
the	O
processor	B-Device
on	O
the	O
BBC	B-Device
Micro	I-Device
with	O
808	O
lines	O
of	O
BASIC	O
,	O
and	O
Arm	B-Architecture
Ltd	O
.	O
retains	O
copies	O
of	O
the	O
code	O
for	O
intellectual	O
property	O
purposes	O
.	O
</s>
<s>
The	O
first	O
prototype	O
ARM	B-Architecture
platforms	O
,	O
the	O
ARM	B-Architecture
Evaluation	O
System	O
and	O
the	O
A500	O
workstation	O
,	O
functioned	O
as	O
second	O
processors	O
attached	O
to	O
the	O
BBC	B-Device
Micro	I-Device
's	O
Tube	B-Device
interface	I-Device
.	O
</s>
<s>
Acorn	O
staff	O
developed	O
the	O
A500	O
's	O
operating	B-General_Concept
system	I-General_Concept
in	O
situ	O
through	O
the	O
Tube	B-Device
until	O
,	O
one	O
by	O
one	O
,	O
the	O
on-board	O
I/O	B-General_Concept
ports	O
were	O
enabled	O
and	O
the	O
A500	O
ran	O
as	O
a	O
stand-alone	O
computer	O
.	O
</s>
<s>
With	O
an	O
upgraded	O
processor	B-Device
this	O
was	O
eventually	O
released	O
during	O
1987	O
as	O
four	O
models	O
in	O
the	O
Archimedes	B-Device
series	O
,	O
the	O
lower-specified	O
two	O
models	O
(	O
512KB	O
and	O
1MB	O
)	O
continuing	O
the	O
BBC	B-Device
Microcomputer	I-Device
brand	O
with	O
the	O
distinctive	O
red	O
function	B-Application
keys	I-Application
.	O
</s>
<s>
Although	O
the	O
Archimedes	B-Device
ultimately	O
was	O
not	O
a	O
major	O
success	O
,	O
the	O
ARM	B-Architecture
family	I-Architecture
of	O
processors	O
has	O
become	O
the	O
dominant	O
processor	B-Device
architecture	O
in	O
mobile	O
embedded	O
consumer	O
devices	O
,	O
particularly	O
mobile	O
telephones	O
.	O
</s>
<s>
It	O
was	O
essentially	O
a	O
1MB	O
Archimedes	B-Device
back	O
in	O
a	O
single	O
case	O
form	O
factor	O
.	O
</s>
<s>
Furber	O
said	O
in	O
2015	O
that	O
he	O
was	O
amazed	O
that	O
the	O
BBC	B-Device
Micro	I-Device
"	O
established	O
this	O
reputation	O
for	O
being	O
reliable	O
,	O
because	O
lots	O
of	O
it	O
was	O
finger-in-the-air	O
engineering	O
"	O
.	O
</s>
<s>
As	O
of	O
2018	O
,	O
thanks	O
to	O
its	O
ready	O
expandability	O
and	O
I/O	B-General_Concept
functions	O
,	O
there	O
are	O
still	O
numbers	O
of	O
BBC	B-Device
Micros	I-Device
in	O
use	O
,	O
and	O
a	O
retrocomputing	O
community	O
of	O
dedicated	O
users	O
finding	O
new	O
tasks	O
for	O
the	O
old	O
hardware	O
.	O
</s>
<s>
They	O
still	O
survive	O
in	O
a	O
few	O
interactive	O
displays	O
in	O
museums	O
across	O
the	O
United	O
Kingdom	O
,	O
and	O
the	O
Jodrell	O
Bank	O
observatory	O
was	O
reported	O
using	O
a	O
BBC	B-Device
Micro	I-Device
to	O
steer	O
its	O
42ft	O
radio	O
telescope	O
in	O
2004	O
.	O
</s>
<s>
The	O
Archimedes	B-Device
came	O
with	O
65Arthur	O
,	O
an	O
emulator	B-Application
which	O
BYTE	B-Application
stated	O
"	O
lets	O
many	O
programs	O
for	O
the	O
BBC	B-Device
Micro	I-Device
run	O
"	O
;	O
other	O
emulators	B-Application
exist	O
for	O
many	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
In	O
March	O
2008	O
,	O
the	O
creators	O
of	O
the	O
BBC	B-Device
Micro	I-Device
met	O
at	O
the	O
Science	O
Museum	O
in	O
London	O
.	O
</s>
<s>
The	O
UK	O
National	O
Museum	O
of	O
Computing	O
at	O
Bletchley	O
Park	O
uses	O
BBC	B-Device
Micros	I-Device
as	O
part	O
of	O
a	O
scheme	O
to	O
educate	O
school	O
children	O
about	O
computer	B-General_Concept
programming	I-General_Concept
.	O
</s>
<s>
In	O
March	O
2012	O
,	O
the	O
BBC	O
and	O
Acorn	O
teams	O
responsible	O
for	O
the	O
BBC	B-Device
Micro	I-Device
and	O
Computer	O
Literacy	O
Project	O
met	O
for	O
a	O
30th	O
anniversary	O
party	O
,	O
entitled	O
"	O
Beeb	O
@30	O
"	O
.	O
</s>
<s>
This	O
was	O
held	O
at	O
Arm	B-Architecture
's	O
offices	O
in	O
Cambridge	O
and	O
was	O
co-hosted	O
by	O
the	O
Centre	O
for	O
Computing	O
History	O
.	O
</s>
<s>
Such	O
developments	O
have	O
included	O
Sprow	O
's	O
1999	O
zip	B-General_Concept
compression	B-General_Concept
utility	I-General_Concept
and	O
a	O
ROM	B-Device
Y2K	O
bugfix	O
for	O
the	O
BBC	B-Device
Master	I-Device
.	O
</s>
<s>
There	O
are	O
also	O
a	O
number	O
of	O
websites	O
still	O
supporting	O
both	O
hardware	O
and	O
software	O
development	O
for	O
the	O
BBC	B-Device
Micros	I-Device
and	O
Acorn	O
in	O
general	O
.	O
</s>
<s>
Model	O
A	O
Model	O
B	O
Model	O
B+64	O
Model	O
B+128	O
Processor	B-Device
MOS	B-Architecture
Technology	I-Architecture
6502A	B-General_Concept
at	O
2	O
MHz	O
Rockwell	O
Semiconductor	O
6512A	O
at	O
2	O
MHz	O
RAM	B-Architecture
16	O
KB	O
(	O
KB	O
is	O
more	O
clearly	O
IEC	O
defined	O
KiB	O
)	O
32	O
KB	O
64	O
KB	O
composed	O
of	O
32	O
KB	O
standard	O
memory	O
,	O
20	O
KB	O
video	O
(	O
Shadow	B-General_Concept
)	O
memory	O
and	O
12	O
KB	O
extended	O
(	O
special	O
Sideways	O
)	O
memory	O
.	O
</s>
<s>
128	O
KB	O
composed	O
of	O
32	O
KB	O
standard	O
memory	O
,	O
20	O
KB	O
video	O
(	O
Shadow	B-General_Concept
)	O
memory	O
and	O
76	O
KB	O
extended	O
(	O
Sideways	O
)	O
memory	O
.	O
</s>
<s>
ROM	B-Device
32	O
KB	O
of	O
ROM	B-Device
composed	O
of	O
a	O
16	O
KB	O
MOS	B-Operating_System
(	O
Machine	O
Operating	B-General_Concept
System	I-General_Concept
)	O
chip	O
,	O
and	O
16	O
KB	O
read-only	O
paged	O
space	O
defaulting	O
to	O
the	O
BBC	B-Language
BASIC	I-Language
chip	O
.	O
</s>
<s>
Four	O
paged	O
16	O
KB	O
ROM	B-Device
sockets	O
standard	O
,	O
expandable	O
to	O
16	O
.	O
</s>
<s>
48	O
KB	O
of	O
ROM	B-Device
composed	O
of	O
16	O
KB	O
MOS	B-Operating_System
,	O
16	O
KB	O
DFS	B-Application
,	O
and	O
16	O
KB	O
read-only	O
paged	O
space	O
defaulting	O
to	O
the	O
BBC	B-Language
BASIC	I-Language
.	O
</s>
<s>
Keyboard	B-Device
Full-travel	O
keyboard	B-Device
with	O
a	O
top	O
row	O
of	O
ten	O
red-orange	O
function	B-Application
keys	I-Application
ƒ0	O
–	O
ƒ9	O
.	O
</s>
<s>
These	O
generated	O
text	B-Data_Structure
semigraphics	I-Data_Structure
when	O
pressed	O
with	O
CTRL	O
or	O
SHIFT	O
,	O
and	O
could	O
be	O
programmed	O
with	O
keyboard	B-Device
macros	O
.	O
</s>
<s>
The	O
arrow	O
keys	O
and	O
BREAK	O
could	O
also	O
serve	O
as	O
function	B-Application
keys	I-Application
.	O
</s>
<s>
Links	O
on	O
the	O
keyboard	B-Device
PCB	O
allowed	O
users	O
to	O
select	O
the	O
behaviour	O
of	O
Shift+Break	O
,	O
and	O
Display	O
Mode	O
on	O
Power-up/Break	O
.	O
</s>
<s>
At	O
least	O
two	O
slightly	O
different	O
keyboards	B-Device
were	O
used	O
during	O
the	O
life	O
of	O
the	O
Model	O
B	O
;	O
both	O
had	O
the	O
same	O
layout	O
,	O
but	O
one	O
had	O
a	O
slightly	O
higher	O
profile	O
on	O
each	O
key	O
.	O
</s>
<s>
6-pin	O
DIN	B-Architecture
digital	O
RGB	O
connector	O
+5	O
V/0	O
V	O
,	O
1	O
V	O
p-p	O
composite	O
colour	O
or	O
monochrome	O
video	O
(	O
link	O
S39	O
)	O
and	O
built-in	O
UHF	O
(	O
PAL	B-Language
)	O
RF	O
modulator	O
.	O
</s>
<s>
Configurable	O
graphics	O
in	O
Modes	O
0	O
–	O
6	O
(	O
see	O
table	O
below	O
)	O
based	O
on	O
the	O
Motorola	B-General_Concept
6845	I-General_Concept
CRT	B-General_Concept
controller	I-General_Concept
or	O
Mode	O
7	O
,	O
a	O
special	O
Teletext	O
mode	O
,	O
based	O
a	O
Mullard	B-General_Concept
SAA5050	I-General_Concept
Teletext	O
chip	O
and	O
only	O
taking	O
1	O
KB	O
of	O
RAM	B-Architecture
.	O
</s>
<s>
Sound	O
Four	O
independent	O
sound	O
channels	O
(	O
one	O
noise	O
and	O
three	O
melodic	O
)	O
using	O
the	O
Texas	B-Device
Instruments	I-Device
SN76489	I-Device
sound	O
chip	O
.	O
</s>
<s>
Phoneme-based	O
speech	O
synthesis	O
using	O
the	O
Texas	O
Instruments	O
TMS5220	B-Application
with	O
a	O
custom	O
Acorn	O
ROM	B-Device
(	O
the	O
"	O
PHROM	O
"	O
,	O
a	O
TMS6100	O
)	O
of	O
Kenneth	O
Kendall	O
's	O
voice	O
(	O
optional	O
)	O
.	O
</s>
<s>
Tape	B-Architecture
storage	I-Architecture
Tape	O
interface	O
(	O
with	O
a	O
relay	O
operated	O
motor	O
control	O
,	O
controlled	O
via	O
2	O
pins	O
on	O
a	O
circular	O
7-pin	O
DIN	B-Architecture
connector	I-Architecture
)	O
,	O
using	O
the	O
CUTS	O
[	O
Computer	O
Users	O
 '	O
Tape	O
Standard ]	O
variation	O
of	O
the	O
Kansas	B-Device
City	I-Device
standard	I-Device
data	O
encoding	O
scheme	O
operating	O
at	O
1200	O
or	O
300	O
baud	O
.	O
</s>
<s>
Disk	B-Device
storage	I-Device
Optional	O
floppy-disk	B-Device
interface	O
based	O
initially	O
on	O
the	O
Intel	O
8271	O
controller	O
and	O
later	O
on	O
the	O
WD1770	B-Device
,	O
also	O
requiring	O
the	O
installation	O
of	O
the	O
DFS	B-Application
(	O
disc	B-Application
filing	I-Application
system	I-Application
)	O
ROM	B-Device
(	O
and	O
of	O
soldered	O
connector	O
on	O
Model	O
A	O
)	O
.	O
</s>
<s>
(	O
-inch	O
floppy	B-Device
drive	I-Device
usually	O
used	O
)	O
–	O
Densities	O
:	O
Single-Sided	O
,	O
Single	O
Density[SS/SD],	O
Single-Sided	O
,	O
Double-Density[SS/DD],	O
Double-Sided	O
,	O
Single-Density[DS/SD]	O
and	O
Double-Sided	O
,	O
Double-Density[DS/DD]	O
.	O
</s>
<s>
Floppy-disk	B-Device
controller	I-Device
based	O
on	O
the	O
Western	O
Digital	O
WD1770	B-Device
controller	O
and	O
DFS	B-Application
ROM	B-Device
as	O
standard	O
(	O
except	O
ANB51	O
,	O
ANB52	O
)	O
.	O
</s>
<s>
Hard-disk	B-Device
storage	I-Device
None	O
(	O
lack	O
of	O
memory	O
)	O
.	O
</s>
<s>
Additional	O
ADFS	B-Device
ROM	B-Device
required	O
,	O
external	O
drive	O
unit	O
connected	O
to	O
the	O
1	O
MHz	O
Bus	O
interface	O
.	O
</s>
<s>
(	O
Winchester	O
Hard	B-Device
disc	I-Device
drives	I-Device
with	O
5	O
MB	O
,	O
10	O
MB	O
or	O
20	O
MB	O
capacities	O
.	O
</s>
<s>
Serial	B-Protocol
interface	I-Protocol
Optional	O
upgrade	O
,	O
soldering	O
required	O
.	O
</s>
<s>
5-pin	O
'	O
domino'-DIN	O
RS-423	O
serial	B-Protocol
port	I-Protocol
.	O
</s>
<s>
Parallel	B-Device
interface	I-Device
Optional	O
upgrade	O
,	O
soldering	O
required	O
.	O
</s>
<s>
26-pin	O
IDC	B-Protocol
Centronics-compatible	O
parallel	B-Device
port	I-Device
.	O
</s>
<s>
20-pin	O
IDC	B-Protocol
"	O
user	O
port	O
"	O
with	O
8	O
general	O
purpose	O
digital	O
I/O	B-General_Concept
pins	O
and	O
two	O
special/trigger	O
sensitive	O
digital	O
pins	O
used	O
for	O
control	O
purposes	O
(	O
for	O
e.g.	O
</s>
<s>
a	O
turtle	O
when	O
using	O
the	O
Logo	B-Device
programming	I-Device
language	I-Device
)	O
.	O
</s>
<s>
DA15	B-Protocol
socket	O
with	O
four	O
8/12	O
bit	O
analogue	O
inputs	O
based	O
on	O
μPD7002	O
IC	O
(	O
suitable	O
for	O
two	O
joysticks	B-Device
)	O
,	O
two	O
inputs	O
suitable	O
for	O
pushbuttons	O
and	O
an	O
input	O
for	O
a	O
light	B-Device
pen	I-Device
.	O
</s>
<s>
34-pin	O
IDC	B-Protocol
connector	I-Protocol
for	O
generic	O
expansion	O
on	O
a	O
"	O
daisy-chain	O
"	O
(	O
used	O
for	O
connecting	O
hard	B-Device
disks	I-Device
,	O
sound	O
synthesisers	O
etc	O
.	O
)	O
.	O
</s>
<s>
The	O
Tube	B-Device
Optional	O
upgrade	O
,	O
soldering	O
required	O
.	O
</s>
<s>
40-pin	O
IDC	B-Protocol
connector	I-Protocol
for	O
external	O
second	O
CPU	B-Device
.	O
</s>
<s>
Options	O
included	O
a	O
second	O
6502	B-General_Concept
,	O
a	O
Zilog	B-General_Concept
Z80	I-General_Concept
,	O
the	O
ARM	B-Architecture
Evaluation	O
System	O
,	O
or	O
a	O
National	B-Device
Semiconductor	I-Device
32016	I-Device
(	O
the	O
latter	O
was	O
either	O
branded	O
"	O
BBC	B-Device
Microcomputer	I-Device
System	I-Device
–	O
32016	B-Device
Second	O
Processor	B-Device
"	O
or	O
"	O
Acorn	O
Computer	O
–	O
Cambridge	O
Co-Processor	O
"	O
)	O
,	O
other	O
vendors	O
added	O
6809	O
,	O
6800	O
,	O
68000	O
and	O
68008	O
.	O
</s>
<s>
A	O
10	O
MHz	O
80186	O
co-processor	O
from	O
a	O
BBC	B-Device
Master	I-Device
can	O
be	O
connected	O
through	O
a	O
co-processor	O
adapter	O
to	O
a	O
BBC	B-Device
Micro	I-Device
,	O
thus	O
enjoying	O
a	O
limited	O
degree	O
of	O
PC	O
compatibility	O
.	O
</s>
<s>
Network	B-Architecture
(	O
optional	O
extra	O
)	O
Econet	B-Device
large-scale	O
low-cost	O
networking	O
system	O
–	O
around	O
100	O
kbit/s	O
using	O
the	O
Motorola	O
68B54	O
(	O
standard	O
on	O
US	O
model	O
)	O
.	O
</s>
<s>
Secondary	O
power	O
output	O
Power	O
supply	O
for	O
external	O
disk	B-Device
drives	I-Device
,	O
6-pin	O
,	O
top	O
to	O
bottom	O
,	O
left	O
to	O
right	O
:	O
0	O
V	O
,	O
0	O
V	O
+5	O
V	O
DC	O
@	O
1.25	O
A	O
,	O
+12	O
V	O
DC	O
@	O
1.25	O
A	O
,	O
NC	O
,	O
−5	O
V	O
DC	O
@75	O
mA	O
,	O
</s>
<s>
Like	O
the	O
IBM	B-Device
PC	I-Device
with	O
the	O
contemporary	O
Color	B-Device
Graphics	I-Device
Adapter	I-Device
,	O
the	O
video	O
output	O
of	O
the	O
BBC	B-Device
Micro	I-Device
could	O
be	O
switched	O
by	O
software	O
between	O
a	O
number	O
of	O
display	O
modes	O
.	O
</s>
<s>
In	O
the	O
first	O
models	O
,	O
the	O
OS	O
and	O
applications	O
were	O
left	O
with	O
the	O
RAM	B-Architecture
left	O
over	O
from	O
the	O
display	O
mode	O
.	O
</s>
<s>
It	O
also	O
made	O
the	O
computer	O
useful	O
as	O
a	O
Prestel	B-General_Concept
terminal	O
.	O
</s>
<s>
The	O
teletext	O
characters	O
were	O
generated	O
using	O
an	O
SAA5050	B-General_Concept
chip	O
,	O
for	O
use	O
with	O
monitors	O
and	O
TV	O
sets	O
without	O
a	O
Teletext	O
receiver	O
.	O
</s>
<s>
Mode	O
7	O
used	O
only	O
1KB	O
for	O
video	O
RAM	B-Architecture
by	O
storing	O
each	O
character	O
as	O
its	O
ASCII	O
code	O
,	O
rather	O
than	O
its	O
bitmap	O
image	O
as	O
was	O
needed	O
for	O
the	O
other	O
modes	O
.	O
</s>
<s>
The	O
palette	O
could	O
be	O
freely	O
reprogrammed	O
without	O
touching	O
display	B-Algorithm
memory	I-Algorithm
.	O
</s>
<s>
Modes	O
3	O
and	O
6	O
were	O
special	O
text-only	O
modes	O
that	O
used	O
less	O
RAM	B-Architecture
by	O
reducing	O
the	O
number	O
of	O
text	O
rows	O
and	O
inserting	O
blank	O
scan	B-Algorithm
lines	I-Algorithm
below	O
each	O
row	O
.	O
</s>
<s>
All	O
modes	O
except	O
mode	O
7	O
supported	O
bitmapped	B-Algorithm
graphics	I-Algorithm
,	O
but	O
graphics	O
commands	O
such	O
as	O
DRAW	O
and	O
PLOT	O
had	O
no	O
effect	O
in	O
the	O
text-only	O
modes	O
.	O
</s>
<s>
The	O
BBC	O
B+	O
and	O
the	O
later	O
Master	O
provided	O
'	O
shadow	B-General_Concept
modes	O
 '	O
,	O
where	O
the	O
1	O
–	O
20KB	O
frame	B-Algorithm
buffer	I-Algorithm
was	O
stored	O
in	O
an	O
alternative	O
RAM	B-Architecture
bank	O
,	O
freeing	O
the	O
main	O
memory	O
for	O
user	O
programs	O
.	O
</s>
<s>
A	O
speech	O
synthesis	O
upgrade	O
based	O
on	O
the	O
Texas	O
Instruments	O
TMS5220	B-Application
featured	O
sampled	O
words	O
spoken	O
by	O
BBC	O
newscaster	O
Kenneth	O
Kendall	O
.	O
</s>
<s>
The	O
Computer	O
Concepts	O
Speech	O
ROM	B-Device
also	O
made	O
use	O
of	O
the	O
TMS5220	B-Application
speech	O
processor	B-Device
but	O
not	O
the	O
speech	O
ROMs	O
,	O
instead	O
driving	O
the	O
speech	O
processor	B-Device
directly	O
.	O
</s>
<s>
The	O
speech	O
upgrade	O
sold	O
poorly	O
and	O
was	O
largely	O
superseded	O
by	O
Superior	B-Device
Software	I-Device
's	O
software-based	O
synthesiser	O
using	O
the	O
standard	O
sound	O
hardware	O
.	O
</s>
<s>
The	O
speech	O
upgrade	O
also	O
added	O
two	O
empty	O
sockets	O
next	O
to	O
the	O
keyboard	B-Device
,	O
intended	O
for	O
16KB	O
serial	B-Protocol
ROM	B-Device
cartridges	O
containing	O
either	O
extra	O
speech	O
phoneme	O
data	O
beyond	O
that	O
held	O
in	O
the	O
speech	O
paged	O
ROM	B-Device
or	O
general	O
software	O
accessed	O
through	O
the	O
ROM	B-Device
Filing	O
System	O
.	O
</s>
<s>
The	O
cut-out	O
space	O
next	O
to	O
the	O
keyboard	B-Device
(	O
nicknamed	O
the	O
"	O
ashtray	O
"	O
)	O
was	O
more	O
commonly	O
used	O
to	O
install	O
other	O
upgrades	O
,	O
such	O
as	O
a	O
ZIF	O
socket	O
for	O
conventional	O
paged	O
ROMs	O
.	O
</s>
<s>
The	B-Device
BBC	I-Device
Domesday	I-Device
Project	I-Device
,	O
a	O
pioneering	O
multimedia	O
experiment	O
,	O
was	O
based	O
on	O
a	O
modified	O
version	O
of	O
the	O
BBC	B-Device
Micro	I-Device
's	O
successor	O
,	O
the	O
BBC	B-Device
Master	I-Device
.	O
</s>
<s>
Musician	O
Vince	O
Clarke	O
of	O
the	O
British	O
synth	O
pop	O
bands	O
Depeche	O
Mode	O
,	O
Yazoo	O
,	O
and	O
Erasure	O
used	O
a	O
BBC	B-Device
Micro	I-Device
(	O
and	O
later	O
a	O
BBC	B-Device
Master	I-Device
)	O
with	O
the	O
UMI	O
music	O
sequencer	O
to	O
compose	O
many	O
hits	O
.	O
</s>
<s>
In	O
music	O
videos	O
from	O
the	O
1980s	O
featuring	O
Vince	O
Clarke	O
,	O
a	O
BBC	B-Device
Micro	I-Device
is	O
often	O
present	O
or	O
provides	O
text	O
and	O
graphics	O
such	O
as	O
a	O
clip	O
for	O
Erasure	O
's	O
"	O
Oh	O
L'Amour	O
"	O
.	O
</s>
<s>
Other	O
bands	O
who	O
have	O
used	O
the	O
BBC	B-Device
Micro	I-Device
for	O
making	O
music	O
are	O
A-ha	O
and	O
the	O
reggae	O
band	O
Steel	O
Pulse	O
.	O
</s>
<s>
Black	O
Uhuru	O
used	O
the	O
Envelope	O
Generator	O
from	O
SYSTEM	O
software	O
(	O
Sheffield	O
)	O
running	O
on	O
a	O
BBC	B-Device
Micro	I-Device
,	O
to	O
create	O
some	O
of	O
the	O
electro-dub	O
sounds	O
on	O
Try	O
It	O
(	O
Anthem	O
album	O
1983	O
)	O
.	O
</s>
<s>
The	O
BBC	B-Device
Micro	I-Device
was	O
used	O
extensively	O
to	O
provide	O
graphics	O
and	O
sound	O
effects	O
for	O
many	O
early	O
1980s	O
BBC	O
TV	O
shows	O
.	O
</s>
<s>
These	O
included	O
,	O
notably	O
,	O
series	O
3	O
and	O
4	O
of	O
The	O
Adventure	O
Game	O
;	O
the	O
children	O
's	O
quiz	O
game	O
"	O
First	O
Class	O
"	O
(	O
where	O
the	O
onscreen	O
scoreboard	O
was	O
provided	O
by	O
a	O
BBC	B-Device
Micro	I-Device
nicknamed	O
"	O
Eugene	O
"	O
)	O
;	O
and	O
numerous	O
1980s	O
episodes	O
of	O
Doctor	O
Who	O
including	O
"	O
Castrovalva	O
"	O
,	O
"	O
The	O
Five	O
Doctors	O
"	O
,	O
and	O
"	O
The	O
Twin	O
Dilemma	O
"	O
.	O
</s>
<s>
In	O
2013	O
,	O
NESTA	O
released	O
a	O
,	O
looking	O
at	O
the	O
history	O
and	O
impact	O
of	O
the	O
machine	O
and	O
The	O
BBC	B-Device
Computer	I-Device
Literacy	I-Device
project	I-Device
.	O
</s>
<s>
The	O
BBC	B-Device
Micro	I-Device
had	O
a	O
lasting	O
technological	O
impact	O
on	O
the	O
education	O
market	O
by	O
introducing	O
an	O
informal	O
educational	O
standard	O
around	O
the	O
hardware	O
and	O
software	O
technologies	O
employed	O
by	O
the	O
range	O
,	O
particularly	O
the	O
use	O
of	O
BBC	B-Language
BASIC	I-Language
,	O
and	O
by	O
establishing	O
a	O
considerable	O
investment	O
by	O
schools	O
in	O
software	O
for	O
the	O
machine	O
.	O
</s>
<s>
Consequently	O
,	O
manufacturers	O
of	O
rival	O
systems	O
such	O
as	O
IBM	B-Device
PC	I-Device
compatibles	O
(	O
and	O
almost-compatibles	O
such	O
as	O
the	O
RM	O
Nimbus	O
)	O
,	O
the	O
Apple	O
Macintosh	O
,	O
and	O
the	O
Commodore	O
Amiga	O
,	O
as	O
well	O
as	O
Acorn	O
as	O
the	O
manufacturer	O
of	O
the	O
BBC	B-Device
Micro	I-Device
's	O
successor	O
,	O
the	O
Archimedes	B-Device
,	O
were	O
compelled	O
to	O
provide	O
a	O
degree	O
of	O
compatibility	O
with	O
the	O
large	O
number	O
of	O
machines	O
already	O
deployed	O
in	O
schools	O
.	O
</s>
