<s>
A	O
BBC	B-Device
Micro	I-Device
expansion	I-Device
unit	I-Device
,	O
for	O
the	O
BBC	B-Device
Micro	I-Device
is	O
one	O
of	O
a	O
number	O
of	O
peripherals	O
in	O
a	O
box	O
with	O
the	O
same	O
profile	O
and	O
styling	O
as	O
the	O
main	O
computer	O
.	O
</s>
<s>
Only	O
one	O
second	O
processor	O
unit	O
could	O
be	O
connected	O
at	O
a	O
time	O
to	O
a	O
BBC	B-Device
Micro	I-Device
,	O
although	O
a	O
Master	O
128	O
could	O
also	O
have	O
a	O
co-processor	O
fitted	O
internally	O
at	O
the	O
same	O
time	O
.	O
</s>
<s>
The	O
terminology	O
of	O
second	O
processor	O
was	O
slightly	O
misleading	O
,	O
since	O
connected	O
and	O
switched	O
on	O
,	O
the	O
system	O
worked	O
on	O
a	O
"	O
host-parasite	O
"	O
model	O
,	O
with	O
the	O
processor	O
in	O
the	O
external	O
unit	O
taking	O
control	O
while	O
the	O
6502	O
in	O
the	O
"	O
main	O
"	O
computer	O
simply	O
took	O
on	O
responsibility	O
for	O
I/O	B-General_Concept
.	O
</s>
<s>
The	O
6502	O
Second	O
Processor	O
(	O
using	O
a	O
65C02	B-General_Concept
)	O
was	O
clocked	O
at	O
3MHz	O
,	O
a	O
full	O
50%	O
faster	O
than	O
the	O
6502	O
inside	O
a	O
BBC	B-Device
Model	I-Device
B	I-Device
,	O
and	O
also	O
had	O
64KB	O
of	O
RAM	B-Architecture
,	O
of	O
which	O
typically	O
30	O
–	O
44KB	O
was	O
free	O
for	O
application	O
data	O
(	O
compared	O
to	O
as	O
little	O
as	O
8.5KB	O
on	O
an	O
unexpanded	O
Model	O
B	O
in	O
graphics	O
mode	O
,	O
or	O
only	O
5.75KB	O
with	O
the	O
disc	O
interface	O
)	O
.	O
</s>
<s>
A	O
version	O
of	O
BBC	B-Language
BASIC	I-Language
II	I-Language
,	O
called	O
Hi-BASIC	O
,	O
was	O
delivered	O
on	O
ROM	O
with	O
this	O
processor	O
together	O
with	O
a	O
DNFS	O
ROM	O
containing	O
the	O
latest	O
versions	O
of	O
the	O
disc	O
filing	O
system	O
(	O
DFS	O
)	O
and	O
Econet	B-Device
network	O
filing	O
system	O
(	O
NFS	O
)	O
.	O
</s>
<s>
The	O
Bitstik	O
CAD	O
system	O
,	O
originally	O
developed	O
by	O
Robocom	O
for	O
the	O
Apple	O
II	O
,	O
was	O
offered	O
as	O
an	O
accessory	O
for	O
the	O
6502	O
Second	O
Processor	O
,	O
also	O
requiring	O
dual	O
80-track	O
floppy	B-Device
drives	I-Device
.	O
</s>
<s>
The	O
Bitstik	O
system	O
itself	O
was	O
introduced	O
with	O
a	O
price	O
of	O
around	O
£375	O
,	O
which	O
combined	O
with	O
floppy	B-Device
drives	I-Device
estimated	O
at	O
£500	O
,	O
the	O
second	O
processor	O
at	O
£199	O
,	O
the	O
cost	O
of	O
the	O
BBC	B-Device
Micro	I-Device
itself	O
at	O
£399	O
,	O
and	O
the	O
price	O
of	O
a	O
colour	O
monitor	O
(	O
Acorn	O
recommending	O
their	O
own	O
RGB	O
monitor	O
)	O
,	O
the	O
total	O
investment	O
was	O
estimated	O
to	O
be	O
between	O
£1500	O
to	O
£2000	O
depending	O
on	O
any	O
particular	O
customer	O
's	O
existing	O
equipment	O
and	O
preferences	O
.	O
</s>
<s>
Various	O
CAD	O
programs	O
were	O
able	O
to	O
take	O
advantage	O
of	O
the	O
6502	O
Second	O
Processor	O
,	O
as	O
was	O
the	O
second	O
processor-specific	O
version	O
of	O
Elite	B-Application
.	O
</s>
<s>
The	O
Z80	B-General_Concept
Second	O
Processor	O
featured	O
a	O
Z80B	B-General_Concept
CPU	O
running	O
at	O
6MHz	O
accessing	O
64KB	O
of	O
RAM	B-Architecture
.	O
</s>
<s>
It	O
required	O
the	O
floppy	B-Device
disc	I-Device
upgrade	O
and	O
,	O
being	O
aimed	O
at	O
business	O
,	O
enabled	O
the	O
BBC	O
system	O
to	O
run	O
CP/M	B-Application
programs	O
.	O
</s>
<s>
As	O
noted	O
in	O
one	O
review	O
,	O
with	O
reference	O
to	O
the	O
intended	O
appeal	O
of	O
the	O
BBC	B-Device
Micro	I-Device
to	O
the	O
home	O
,	O
education	O
and	O
business	O
markets	O
,	O
with	O
the	O
Z80	B-General_Concept
second	O
processor	O
"	O
Acorn	O
have	O
completed	O
the	B-Device
BBC	I-Device
Microcomputer	I-Device
system	I-Device
as	O
originally	O
planned	O
"	O
.	O
</s>
<s>
The	O
product	O
was	O
launched	O
in	O
mid-1984	O
at	O
a	O
price	O
of	O
£299	O
and	O
included	O
an	O
estimated	O
£3000	O
worth	O
of	O
bundled	O
software	O
that	O
included	O
the	O
CP/M	B-Application
2.2	O
operating	B-General_Concept
system	I-General_Concept
itself	O
(	O
with	O
GSX	O
graphics	O
)	O
,	O
CIS	O
Cobol	O
and	O
utilities	O
from	O
Microfocus	O
,	O
the	O
Memo	O
Plan	O
,	O
Graph	O
Plan	O
and	O
File	O
Plan	O
office	O
applications	O
from	O
Chang	O
Laboratories	O
,	O
the	O
Accountant	O
and	O
Nucleus	O
packages	O
from	O
Compact	O
Accounting	O
Services	O
,	O
and	O
two	O
BASIC	O
implementations	O
:	O
Z80	B-General_Concept
BBC	B-Language
BASIC	I-Language
and	O
Mallard	O
Professional	O
BASIC	O
.	O
</s>
<s>
Despite	O
"	O
a	O
policy	O
of	O
continuous	O
improvement	O
"	O
,	O
Acorn	O
apparently	O
abandoned	O
plans	O
to	O
update	O
the	O
software	O
bundle	O
in	O
mid-1986	O
due	O
to	O
a	O
review	O
of	O
the	O
CP/M	B-Application
market	O
.	O
</s>
<s>
Other	O
suppliers	O
continued	O
to	O
support	O
the	O
Z80	B-General_Concept
,	O
delivering	O
Z80	B-General_Concept
second	O
processor	O
hardware	O
and	O
software	O
bundles	O
,	O
such	O
as	O
the	O
Task-Master	O
which	O
combined	O
an	O
externally	O
connected	O
second	O
processor	O
,	O
compatible	O
with	O
the	O
BBC	B-Device
Model	I-Device
B	I-Device
,	O
B+	O
and	O
Master	O
,	O
and	O
a	O
suite	O
of	O
software	O
including	O
a	O
CP/M	B-Application
2.2-compatible	O
operating	B-General_Concept
system	I-General_Concept
known	O
as	O
ZCPR3	O
and	O
Borland	O
's	O
Turbo	O
Pascal	B-Application
plus	O
other	O
development	O
tools	O
.	O
</s>
<s>
Originally	O
referred	O
to	O
as	O
the	O
Gluon	O
,	O
a	O
National	B-Device
Semiconductor	I-Device
32016	I-Device
second	O
processor	O
solution	O
was	O
apparently	O
planned	O
for	O
the	O
BBC	B-Device
Micro	I-Device
and	O
for	O
other	O
8-bit	O
microcomputers	O
,	O
with	O
the	O
BBC	B-Device
Micro	I-Device
version	O
employing	O
the	O
Tube	O
interface	O
and	O
offering	O
a	O
quarter	O
of	O
a	O
megabyte	O
of	O
RAM	B-Architecture
,	O
whereas	O
the	O
"	O
Universal	O
Gluon	O
"	O
would	O
be	O
connected	O
to	O
a	O
microcomputer	O
acting	O
as	O
a	O
terminal	O
using	O
a	O
serial	O
or	O
parallel	O
interface	O
,	O
offer	O
up	O
to	O
1MB	O
of	O
RAM	B-Architecture
,	O
up	O
to	O
5MB	O
of	O
hard	O
disk	O
storage	O
,	O
and	O
either	O
a	O
minimal	O
operating	B-General_Concept
system	I-General_Concept
or	O
Unix	O
.	O
</s>
<s>
Subsequent	O
news	O
of	O
the	O
second	O
processor	O
indicated	O
the	O
renaming	O
of	O
the	O
product	O
,	O
dropping	O
the	O
Gluon	O
name	O
,	O
the	O
use	O
of	O
Acorn	O
's	O
own	O
Panos	B-Operating_System
operating	B-General_Concept
system	I-General_Concept
instead	O
of	O
Xenix	O
,	O
with	O
availability	O
in	O
1985	O
.	O
</s>
<s>
The	O
product	O
that	O
was	O
eventually	O
delivered	O
is	O
a	O
sophisticated	O
second	O
processor	O
expansion	O
sometimes	O
branded	O
as	O
"	O
Acorn	O
Cambridge	O
Co-Processor	O
"	O
with	O
an	O
Acorn	O
logo	O
,	O
and	O
sometimes	O
as	O
"	O
BBC	B-Device
Microcomputer	I-Device
System	I-Device
32016	B-Device
Second	O
Processor	O
"	O
along	O
with	O
the	O
BBC	B-Device
Micro	I-Device
's	O
owl	O
logo	O
.	O
</s>
<s>
The	O
device	O
uses	O
the	O
32016	B-Device
CPU	O
and	O
32081	O
FPU	O
running	O
at	O
6MHz	O
.	O
</s>
<s>
It	O
runs	O
the	O
non-graphical	O
Panos	B-Operating_System
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
Various	O
programming	O
languages	O
are	O
available	O
including	O
C	B-Language
,	O
FORTRAN	B-Application
,	O
Lisp	B-Language
,	O
and	O
Pascal	B-Application
,	O
in	O
addition	O
to	O
a	O
version	O
of	O
BBC	B-Language
BASIC	I-Language
.	O
</s>
<s>
Initially	O
offered	O
as	O
the	O
32016	B-Device
Second	O
Processor	O
with	O
256KB	O
of	O
RAM	B-Architecture
,	O
the	O
expansion	O
was	O
subsequently	O
delivered	O
as	O
the	O
Cambridge	O
Co-Processor	O
with	O
512KB	O
or	O
1MB	O
of	O
RAM	B-Architecture
as	O
standard	O
.	O
</s>
<s>
The	O
32016	B-Device
second	O
processor	O
is	O
also	O
present	O
as	O
part	O
of	O
the	O
Acorn	B-Device
Cambridge	I-Device
Workstation	I-Device
using	O
an	O
8MHz	O
CPU	O
and	O
4MB	O
of	O
RAM	B-Architecture
,	O
sold	O
as	O
part	O
of	O
the	O
Acorn	B-Device
Business	I-Device
Computer	I-Device
line	O
.	O
</s>
<s>
The	O
second	O
processor	O
board	O
was	O
also	O
able	O
to	O
use	O
64-kilobit	O
or	O
256-kilobit	O
RAM	B-Architecture
devices	O
,	O
thus	O
allowing	O
the	O
earlier	O
256KB	O
specification	O
to	O
be	O
upgraded	O
to	O
1MB	O
as	O
the	O
higher-density	O
devices	O
became	O
available	O
and	O
affordable	O
.	O
</s>
<s>
This	O
allowed	O
the	O
BBC	B-Device
B	I-Device
and	O
B+	O
to	O
use	O
the	O
Turbo	O
board	O
(	O
4MHz	O
65C102	O
with	O
64KB	O
of	O
RAM	B-Architecture
)	O
and	O
the	O
Master	O
512	O
board	O
(	O
10MHz	O
80186	B-Device
with	O
512KB	O
of	O
RAM	B-Architecture
)	O
,	O
by	O
fitting	O
them	O
into	O
this	O
expansion	O
unit	O
.	O
</s>
<s>
The	O
ARM	B-Architecture
Evaluation	O
System	O
was	O
announced	O
in	O
July	O
1986	O
for	O
fourth	O
quarter	O
availability	O
at	O
a	O
cost	O
of	O
£	O
4,500	O
plus	O
VAT	O
.	O
</s>
<s>
As	O
one	O
of	O
the	O
first	O
production	O
RISC	B-Architecture
processors	I-Architecture
,	O
the	O
ARM	B-Architecture
Evaluation	O
System	O
was	O
part	O
of	O
the	O
development	O
programme	O
leading	O
to	O
the	O
Acorn	B-Device
Archimedes	I-Device
and	O
its	O
early	O
Arthur	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
The	O
ARM	B-Architecture
1	O
processor	O
was	O
clocked	O
at	O
8MHz	O
,	O
and	O
was	O
fitted	O
with	O
2MB	O
or	O
4MB	O
of	O
RAM	B-Architecture
.	O
</s>
<s>
In	O
2006	O
,	O
a	O
new	O
ARM	B-Architecture
processor	I-Architecture
board	O
using	O
an	O
ARM7TDMI	O
processor	O
was	O
designed	O
and	O
sold	O
,	O
without	O
an	O
enclosure	O
but	O
able	O
to	O
fit	O
within	O
the	O
original	O
case	O
.	O
</s>
<s>
Z80	B-General_Concept
second	O
processors	O
offering	O
64KB	O
of	O
RAM	B-Architecture
and	O
CP/M	B-Application
-compatible	O
operating	B-General_Concept
systems	I-General_Concept
included	O
the	O
Multiform	O
Z80	B-General_Concept
from	O
Technomatic	O
,	O
priced	O
at	O
£299	O
,	O
and	O
several	O
products	O
from	O
Torch	O
Computers	O
such	O
as	O
the	O
Z80	B-General_Concept
Disc	O
Pack	O
(	O
ZDP	O
)	O
and	O
ZEP	O
,	O
the	O
latter	O
priced	O
at	O
around	O
£340	O
.	O
</s>
<s>
Torch	O
also	O
offered	O
the	O
Intel	O
8088-based	O
Graduate	O
running	O
MS-DOS	O
and	O
having	O
256KB	O
of	O
RAM	B-Architecture
and	O
dual	O
floppy	B-Device
drives	I-Device
,	O
priced	O
at	O
£1000	O
plus	O
VAT	O
,	O
and	O
the	O
Z80	B-General_Concept
-	O
and	O
68000-based	O
HDP68K	O
or	O
Unicorn	O
,	O
the	O
latter	O
running	O
Unix	O
and	O
having	O
256KB	O
of	O
RAM	B-Architecture
or	O
more	O
,	O
floppy	B-Device
drive	I-Device
and	O
20MB	O
hard	O
drive	O
.	O
</s>
<s>
Cumana	O
chose	O
to	O
produce	O
a	O
68008	O
second	O
processor	O
running	O
the	O
OS-9	O
operating	B-General_Concept
system	I-General_Concept
that	O
was	O
installed	O
into	O
the	O
6502	O
CPU	O
socket	O
,	O
relocating	O
the	O
6502	O
to	O
the	O
second	O
processor	O
board	O
itself	O
,	O
and	O
providing	O
512KB	O
RAM	B-Architecture
and	O
its	O
own	O
disk	O
controller	O
.	O
</s>
<s>
Performance	O
concerns	O
associated	O
with	O
the	O
68008	O
,	O
due	O
to	O
experiences	O
with	O
the	O
Sinclair	B-Device
QL	I-Device
,	O
were	O
alleviated	O
through	O
the	O
presence	O
of	O
"	O
plenty	O
of	O
sub	O
processors	O
"	O
,	O
these	O
utilised	O
for	O
managing	O
peripherals	O
including	O
control	O
of	O
floppy	B-Device
and	O
SASI-compatible	O
hard	O
drives	O
,	O
coupled	O
with	O
the	O
use	O
of	O
a	O
relatively	O
fast	O
8MHz	O
CPU	O
.	O
</s>
<s>
Due	O
to	O
the	O
method	O
of	O
interfacing	O
the	O
second	O
processor	O
to	O
the	O
host	O
system	O
,	O
the	O
board	O
was	O
also	O
able	O
to	O
give	O
the	O
68008	O
direct	O
access	O
to	O
the	O
host	O
machine	O
's	O
user	O
port	O
,	O
1MHz	O
bus	O
and	O
analogue	O
port	O
,	O
permitting	O
the	O
development	O
of	O
programs	O
in	O
languages	O
like	O
C	B-Language
to	O
utilise	O
these	O
capabilities	O
.	O
</s>
<s>
Indeed	O
,	O
Cumana	O
bundled	O
an	O
estimated	O
£3000	O
worth	O
of	O
software	O
with	O
the	O
board	O
,	O
including	O
assembly	O
language	O
,	O
BASIC	O
,	O
Pascal	B-Application
and	O
C	B-Language
language	I-Language
tools	O
,	O
the	O
"	O
fourth	O
generation	O
language	O
"	O
Sculptor	O
,	O
word	O
processing	O
,	O
spellchecking	O
,	O
mail	O
merge	O
,	O
spreadsheet	O
and	O
database	O
applications	O
,	O
plus	O
a	O
screen	O
editor	O
.	O
</s>
<s>
Cambridge	O
Microprocessor	O
Systems	O
and	O
Control	O
Universal	O
both	O
offered	O
6809	O
second	O
processor	O
solutions	O
supporting	O
the	O
FLEX	O
operating	B-General_Concept
system	I-General_Concept
.	O
</s>
<s>
Permanent	O
Memory	O
Systems	O
produced	O
a	O
6502	O
second	O
processor	O
,	O
the	O
B2P	O
6502	O
,	O
employing	O
a	O
2MHz	O
65C02	B-General_Concept
processor	O
as	O
opposed	O
to	O
the	O
faster	O
6502	O
device	O
used	O
by	O
the	O
Acorn	O
6502	O
Second	O
Processor	O
unit	O
together	O
with	O
64KB	O
of	O
RAM	B-Architecture
.	O
</s>
<s>
The	O
adapters	O
connected	O
to	O
the	O
BBC	B-Device
Micro	I-Device
's	O
1MHz	O
bus	O
interface	O
.	O
</s>
<s>
The	O
teletext-like	O
"	O
Mode	O
7	O
"	O
display	O
mode	O
inside	O
the	O
8-bit	O
BBC	B-Device
Micros	I-Device
made	O
a	O
broadcast	O
teletext	O
adapter	O
an	O
obvious	O
expansion	O
,	O
and	O
the	O
BBC	O
would	O
broadcast	O
telesoftware	O
free	O
over	O
Ceefax	O
.	O
</s>
<s>
The	O
adapter	O
itself	O
was	O
mains	O
powered	O
with	O
its	O
own	O
power	O
switch	O
matching	O
the	O
one	O
on	O
the	O
BBC	B-Device
microcomputer	I-Device
.	O
</s>
<s>
The	O
Prestel	B-General_Concept
adapter	O
was	O
essentially	O
a	O
modem	B-Application
fitted	O
into	O
the	O
"	O
cheese	O
wedge	O
"	O
-shaped	O
case	O
.	O
</s>
<s>
It	O
enabled	O
the	O
user	O
to	O
connect	O
to	O
Prestel	B-General_Concept
viewdata	B-Application
services	O
over	O
a	O
telephone	O
line	O
.	O
</s>
<s>
Allowed	O
the	O
BBC	B-Device
Micro	I-Device
to	O
talk	O
over	O
an	O
IEEE-488	O
bus	O
to	O
specialised	O
equipment	O
.	O
</s>
<s>
Used	O
to	O
connect	O
two	O
Econet	B-Device
segments	O
together	O
.	O
</s>
<s>
An	O
Econet	B-Device
bridge	O
is	O
capable	O
of	O
automatically	O
learning	O
a	O
simple	O
network	O
topology	O
and	O
selectively	O
forwarding	O
packets	O
from	O
one	O
LAN	O
segment	O
to	O
the	O
other	O
using	O
a	O
simple	O
routing	O
table	O
based	O
on	O
the	O
contents	O
of	O
the	O
network	O
byte	O
in	O
the	O
Econet	B-Device
packet	O
.	O
</s>
<s>
The	O
Econet	B-Device
bridge	O
is	O
unique	O
among	O
the	O
cheese	O
wedge	O
expansions	O
,	O
in	O
that	O
it	O
is	O
a	O
stand-alone	O
device	O
that	O
does	O
not	O
require	O
a	O
BBC	B-Device
computer	I-Device
to	O
operate	O
.	O
</s>
