<s>
The	O
Acorn	B-Device
Electron	I-Device
(	O
nicknamed	O
the	O
Elk	O
inside	O
Acorn	O
and	O
beyond	O
)	O
was	O
a	O
lower-cost	O
alternative	O
to	O
the	O
BBC	B-Device
Micro	I-Device
educational/home	O
computer	O
,	O
also	O
developed	O
by	O
Acorn	O
Computers	O
Ltd	O
,	O
to	O
provide	O
many	O
of	O
the	O
features	O
of	O
that	O
more	O
expensive	O
machine	O
at	O
a	O
price	O
more	O
competitive	O
with	O
that	O
of	O
the	O
ZX	B-Operating_System
Spectrum	I-Operating_System
.	O
</s>
<s>
It	O
had	O
32	O
kilobytes	O
of	O
RAM	B-Architecture
,	O
and	O
its	O
ROM	B-Device
included	O
BBC	B-Language
BASIC	I-Language
II	O
together	O
with	O
the	O
operating	B-Operating_System
system	I-Operating_System
.	O
</s>
<s>
The	O
Electron	O
was	O
able	O
to	O
save	O
and	O
load	O
programs	O
onto	O
audio	B-Device
cassette	I-Device
via	O
a	O
supplied	O
cable	O
that	O
connected	O
it	O
to	O
any	O
standard	O
tape	O
recorder	O
that	O
had	O
the	O
correct	O
sockets	O
.	O
</s>
<s>
It	O
was	O
capable	O
of	O
bitmapped	O
graphics	O
,	O
and	O
could	O
use	O
either	O
a	O
television	O
set	O
,	O
a	O
colour	O
(	O
RGB	O
)	O
monitor	O
or	O
a	O
monochrome	B-Device
monitor	I-Device
as	O
its	O
display	O
.	O
</s>
<s>
Several	O
expansions	O
were	O
made	O
available	O
to	O
provide	O
many	O
of	O
the	O
capabilities	O
omitted	O
from	O
the	O
BBC	B-Device
Micro	I-Device
.	O
</s>
<s>
Acorn	O
introduced	O
a	O
general-purpose	O
expansion	O
unit	O
,	O
the	O
Plus	O
1	O
,	O
offering	O
analogue	O
joystick	O
and	O
parallel	O
ports	O
,	O
together	O
with	O
cartridge	B-Protocol
slots	O
into	O
which	O
ROM	B-Protocol
cartridges	I-Protocol
,	O
providing	O
software	O
,	O
or	O
other	O
kinds	O
of	O
hardware	O
expansions	O
,	O
such	O
as	O
disc	O
interfaces	O
,	O
could	O
be	O
inserted	O
.	O
</s>
<s>
Acorn	O
also	O
produced	O
a	O
dedicated	O
disc	O
expansion	O
,	O
the	O
Plus	O
3	O
,	O
featuring	O
a	O
disc	O
controller	O
and	O
3.5-inch	O
floppy	B-Device
drive	I-Device
.	O
</s>
<s>
With	O
production	O
effectively	O
discontinued	O
by	O
Acorn	O
as	O
early	O
as	O
1985	O
,	O
and	O
with	O
the	O
machine	O
offered	O
in	O
bundles	O
with	O
games	O
and	O
expansions	O
,	O
later	O
being	O
substantially	O
discounted	O
by	O
retailers	O
,	O
a	O
revival	O
in	O
demand	O
for	O
the	O
Electron	O
supported	O
a	O
market	O
for	O
software	O
and	O
expansions	O
without	O
Acorn	O
's	O
involvement	O
,	O
with	O
its	O
market	O
for	O
games	O
also	O
helping	O
to	O
sustain	O
the	O
continued	O
viability	O
of	O
games	O
production	O
for	O
the	O
BBC	B-Device
Micro	I-Device
.	O
</s>
<s>
After	O
Acorn	O
Computers	O
released	O
the	O
BBC	B-Device
Micro	I-Device
,	O
executives	O
believed	O
that	O
the	O
company	O
needed	O
a	O
less-expensive	O
computer	O
for	O
the	O
mass	O
market	O
.	O
</s>
<s>
In	O
May	O
1982	O
,	O
when	O
asked	O
about	O
the	O
recently	O
announced	O
Sinclair	B-Operating_System
ZX	I-Operating_System
Spectrum	I-Operating_System
's	O
potential	O
to	O
hurt	O
sales	O
of	O
the	O
BBC	B-Device
Micro	I-Device
,	O
priced	O
at	O
£125	O
for	O
the	O
16K	O
model	O
compared	O
to	O
around	O
twice	O
that	O
price	O
for	O
the	O
16K	O
BBC	B-Device
Model	I-Device
A	I-Device
,	O
Acorn	O
co-founder	O
Hermann	O
Hauser	O
responded	O
that	O
in	O
the	O
third	O
quarter	O
of	O
that	O
year	O
Acorn	O
would	O
release	O
a	O
new	O
£120	O
–	O
150	O
computer	O
which	O
"	O
will	O
probably	O
be	O
called	O
the	O
Electron	O
"	O
,	O
a	O
form	O
of	O
"	O
miniaturised	O
BBC	B-Device
Micro	I-Device
"	O
,	O
having	O
32	O
KB	O
of	O
RAM	B-Architecture
and	O
32	O
KB	O
of	O
ROM	B-Device
,	O
with	O
"	O
higher	O
resolution	O
graphics	O
than	O
those	O
offered	O
by	O
the	O
Spectrum	O
"	O
.	O
</s>
<s>
In	O
order	O
to	O
reduce	O
component	O
costs	O
,	O
and	O
to	O
prevent	O
cloning	O
,	O
the	O
company	O
reduced	O
the	O
number	O
of	O
chips	O
in	O
the	O
Electron	O
from	O
the	O
102	O
on	O
the	O
BBC	B-Device
Micro	I-Device
's	O
motherboard	O
to	O
"	O
something	O
like	O
12	O
to	O
14	O
chips	O
"	O
with	O
most	O
functionality	O
on	O
a	O
single	O
2,400	O
-gate	O
Uncommitted	O
Logic	O
Array	O
(	O
ULA	O
)	O
.	O
</s>
<s>
Praise	O
was	O
also	O
forthcoming	O
for	O
the	O
Electron	O
's	O
keyboard	B-Device
which	O
was	O
regarded	O
as	O
being	O
better	O
than	O
most	O
of	O
its	O
low-cost	O
peers	O
,	O
with	O
only	O
the	O
VIC-20	B-Device
being	O
comparable	O
.	O
</s>
<s>
In	O
one	O
review	O
,	O
the	O
keyboard	B-Device
was	O
even	O
regarded	O
as	O
better	O
than	O
the	O
one	O
in	O
the	O
BBC	B-Device
Micro	I-Device
.	O
</s>
<s>
The	O
provision	O
of	O
screen	O
modes	O
supporting	O
80	O
columns	O
of	O
readable	O
text	O
and	O
graphics	O
resolutions	O
of	O
was	O
described	O
as	O
"	O
unrivalled	O
by	O
every	O
machine	O
up	O
to	O
the	O
BBC	B-Device
Model	I-Device
B	I-Device
itself	O
"	O
,	O
although	O
the	O
absence	O
of	O
a	O
teletext	O
mode	O
was	O
also	O
noted	O
,	O
typically	O
for	O
the	O
low	O
memory	O
usage	O
characteristics	O
of	O
that	O
mode	O
,	O
but	O
one	O
reviewer	O
thought	O
the	O
absence	O
of	O
a	O
"	O
software	O
simulation	O
of	O
a	O
teletext	O
screen	O
"	O
was	O
a	O
"	O
lazy	O
omission	O
"	O
even	O
if	O
it	O
would	O
have	O
to	O
be	O
"	O
awfully	O
slow	O
and	O
take	O
up	O
piles	O
of	O
memory	O
"	O
.	O
</s>
<s>
While	O
its	O
speed	O
was	O
acceptable	O
compared	O
to	O
its	O
immediate	O
competition	O
,	O
the	O
Electron	O
was	O
,	O
however	O
,	O
rather	O
slower	O
than	O
the	O
BBC	B-Device
Micro	I-Device
with	O
one	O
review	O
noting	O
that	O
games	O
designed	O
for	O
the	O
BBC	B-Device
Micro	I-Device
ran	O
"	O
at	O
less	O
than	O
half	O
the	O
speed	O
,	O
with	O
very	O
significant	O
effects	O
on	O
their	O
appeal	O
"	O
.	O
</s>
<s>
The	O
reduced	O
performance	O
can	O
be	O
attributed	O
to	O
the	O
use	O
of	O
a	O
4-bit	O
wide	O
memory	O
system	O
instead	O
of	O
the	O
8-bit	O
wide	O
memory	O
system	O
of	O
the	O
BBC	B-Device
Micro	I-Device
to	O
reduce	O
cost	O
.	O
</s>
<s>
Due	O
to	O
needing	O
two	O
accesses	O
to	O
the	O
memory	O
instead	O
of	O
one	O
to	O
fetch	O
each	O
byte	O
,	O
along	O
with	O
contention	O
with	O
the	O
video	O
hardware	O
also	O
needing	O
access	O
,	O
reading	O
or	O
writing	O
RAM	B-Architecture
was	O
much	O
slower	O
than	O
on	O
the	O
BBC	B-Device
Micro	I-Device
.	O
</s>
<s>
Despite	O
some	O
uncertainty	O
about	O
Acorn	O
's	O
target	O
demographic	O
for	O
the	O
Electron	O
,	O
some	O
noted	O
the	O
potential	O
for	O
the	O
machine	O
in	O
education	O
given	O
its	O
robustness	O
,	O
but	O
also	O
given	O
its	O
price	O
,	O
noting	O
that	O
the	O
high	O
price	O
of	O
BBC	B-Device
Model	I-Device
B	I-Device
machines	O
seemed	O
"	O
rarely	O
justified	O
by	O
their	O
actual	O
practical	O
applications	O
in	O
schools	O
"	O
.	O
</s>
<s>
Nevertheless	O
,	O
reviewers	O
anticipated	O
that	O
the	O
Electron	O
would	O
sell	O
well	O
at	O
the	O
lower	O
end	O
of	O
the	O
market	O
,	O
with	O
projected	O
sales	O
of	O
100,000	O
units	O
by	O
Christmas	O
1983	O
,	O
helped	O
by	O
the	O
Electron	O
's	O
software	O
compatibility	O
with	O
the	O
BBC	B-Device
Micro	I-Device
and	O
the	O
already	O
established	O
reputation	O
of	O
its	O
predecessor	O
.	O
</s>
<s>
Although	O
Acorn	O
had	O
based	O
its	O
expansion	O
into	O
the	O
United	O
States	O
on	O
the	O
BBC	B-Device
Micro	I-Device
,	O
the	O
company	O
did	O
have	O
plans	O
to	O
introduce	O
the	O
Electron	O
at	O
a	O
later	O
time	O
,	O
with	O
Chris	O
Curry	O
having	O
indicated	O
"	O
a	O
very	O
heavy	O
push	O
overseas	O
"	O
involving	O
both	O
the	O
BBC	B-Device
Micro	I-Device
and	O
Electron	O
.	O
</s>
<s>
Production	O
difficulties	O
at	O
Astec	O
in	O
Malaysia	O
delayed	O
the	O
machine	O
's	O
introduction	O
,	O
forcing	O
Acorn	O
to	O
look	O
to	O
other	O
manufacturers	O
such	O
as	O
AB	O
Electronics	O
in	O
Wales	O
and	O
Wongs	O
in	O
Hong	O
Kong	O
(	O
an	O
original	O
equipment	O
manufacturer	O
making	O
over	O
30	O
million	O
circuit	O
boards	O
a	O
year	O
,	O
along	O
with	O
power	O
supplies	O
and	O
plastic	O
housings	O
,	O
for	O
companies	O
such	O
as	O
IBM	O
,	O
Xerox	O
,	O
Atari	O
,	O
and	O
Apple	O
,	O
including	O
units	O
made	O
for	O
Acorn	O
for	O
the	O
BBC	B-Device
Micro	I-Device
)	O
.	O
</s>
<s>
Renewed	O
efforts	O
were	O
made	O
to	O
sell	O
the	O
machine	O
,	O
bundling	O
it	O
with	O
Acorn	O
's	O
own	O
expansions	O
and	O
software	O
,	O
such	O
as	O
one	O
package	O
adding	O
the	O
Plus	O
1	O
expansion	O
,	O
joysticks	O
and	O
a	O
ROM	B-Protocol
cartridge	I-Protocol
game	O
to	O
the	O
base	O
machine	O
for	O
a	O
total	O
price	O
of	O
£219	O
.	O
</s>
<s>
However	O
,	O
Acorn	O
subsequently	O
released	O
the	O
Master	O
Compact	O
a	O
model	O
in	O
the	O
Master	B-Device
series	I-Device
of	O
microcomputers	B-Architecture
with	O
fewer	O
BBC	O
Micro-style	O
ports	O
and	O
a	O
similar	O
expansion	O
connector	O
to	O
that	O
used	O
by	O
the	O
Electron	O
with	O
the	O
home	O
audience	O
specifically	O
in	O
mind	O
.	O
</s>
<s>
Superficial	O
similarities	O
between	O
the	O
Compact	O
and	O
Acorn	B-Device
Communicator	I-Device
,	O
together	O
with	O
technical	O
similarities	O
between	O
the	O
Electron	O
(	O
particularly	O
when	O
expanded	O
in	O
the	O
form	O
of	O
the	O
Merlin	O
M2105	O
)	O
and	O
the	O
Communicator	O
,	O
may	O
also	O
have	O
driven	O
rumours	O
of	O
an	O
updated	O
Electron	O
model	O
.	O
</s>
<s>
A	O
more	O
substantial	O
emphasis	O
on	O
the	O
"	O
home	O
,	O
music	O
and	O
hobby	O
sectors	O
"	O
came	O
with	O
the	O
appointment	O
of	O
a	O
dedicated	O
marketing	O
manager	O
in	O
1989	O
following	O
the	O
launch	O
of	O
the	O
BBC	O
A3000	O
in	O
the	O
Acorn	B-Device
Archimedes	I-Device
range	O
.	O
</s>
<s>
Several	O
features	O
that	O
would	O
later	O
be	O
associated	O
with	O
the	O
BBC	B-Device
Master	I-Device
and	O
Archimedes	B-Device
first	O
appeared	O
as	O
features	O
of	O
Electron	O
expansion	O
units	O
,	O
including	O
ROM	B-Protocol
cartridge	I-Protocol
slots	O
and	O
the	O
Advanced	B-Device
Disc	I-Device
Filing	I-Device
System	I-Device
,	O
a	O
hierarchical	O
improvement	O
to	O
the	O
BBC	O
's	O
original	O
Disc	B-Application
Filing	I-Application
System	I-Application
.	O
</s>
<s>
Having	O
been	O
envisaged	O
as	O
the	O
basis	O
of	O
a	O
portable	O
computer	O
with	O
"	O
a	O
very	O
strong	O
emphasis	O
on	O
communications	O
"	O
during	O
its	O
development	O
,	O
supporting	O
both	O
modem	B-Application
and	O
Econet	B-Device
interfaces	O
,	O
the	O
BT	O
Merlin	O
M2105	O
product	O
subsequently	O
combined	O
the	O
Electron	O
with	O
communications	O
functionality	O
,	O
and	O
the	O
Acorn	B-Device
Communicator	I-Device
developed	O
such	O
concepts	O
further	O
,	O
introducing	O
networking	O
support	O
.	O
</s>
<s>
While	O
it	O
may	O
not	O
have	O
been	O
as	O
popular	O
as	O
the	O
Spectrum	O
,	O
Commodore	O
64	O
or	O
Amstrad	B-Device
CPC	I-Device
,	O
it	O
did	O
sell	O
in	O
sufficient	O
numbers	O
to	O
ensure	O
that	O
new	O
software	O
titles	O
from	O
established	O
producers	O
were	O
being	O
produced	O
right	O
up	O
until	O
the	O
early	O
1990s	O
,	O
with	O
mainstream	O
publications	O
dedicated	O
to	O
the	O
machine	O
having	O
effectively	O
supported	O
it	O
for	O
five	O
years	O
beyond	O
the	O
point	O
at	O
which	O
Acorn	O
's	O
own	O
support	O
had	O
ceased	O
.	O
</s>
<s>
The	O
first	O
expansions	O
were	O
largely	O
joystick	O
and	O
printer	O
interfaces	O
or	O
sideways	O
ROM	B-Device
boards	O
.	O
</s>
<s>
Acorn	O
's	O
own	O
expansion	O
strategy	O
was	O
led	O
by	O
the	O
Plus	O
1	O
which	O
offered	O
a	O
combination	O
of	O
ports	O
and	O
cartridge	B-Protocol
connectors	O
,	O
followed	O
by	O
the	O
Plus	O
3	O
disc	O
drive	O
unit	O
,	O
but	O
by	O
early	O
1986	O
the	O
more	O
general	O
range	O
of	O
expansions	O
had	O
broadened	O
to	O
include	O
floppy	B-Device
drive	I-Device
and	O
RS423	O
interfaces	O
,	O
Teletext	O
adapters	O
,	O
and	O
other	O
fundamental	O
enhancements	O
to	O
the	O
base	O
machine	O
.	O
</s>
<s>
Alongside	O
announcements	O
of	O
Acorn	O
's	O
then-unreleased	O
Plus	O
1	O
,	O
Solidisk	O
previewed	O
a	O
General	O
Purpose	O
Interface	O
for	O
the	O
Electron	O
in	O
early	O
1984	O
offering	O
a	O
Centronics	B-Device
printer	I-Device
port	I-Device
,	O
switched	O
joystick	O
port	O
,	O
user	O
port	O
,	O
sideways	O
ROM	B-Device
sockets	O
,	O
and	O
mini-cartridge	O
sockets	O
supported	O
by	O
the	O
6522	B-Device
versatile	B-Device
interface	I-Device
adapter	I-Device
(	O
VIA	O
)	O
chip	O
.	O
</s>
<s>
The	O
Plus	O
1	O
itself	O
was	O
released	O
in	O
mid-1984	O
,	O
introducing	O
the	O
influential	O
cartridge	B-Protocol
format	O
for	O
expansions	O
ultimately	O
used	O
by	O
several	O
other	O
companies	O
.	O
</s>
<s>
The	O
Acorn	O
Plus	O
1	O
added	O
two	O
ROM	B-Protocol
cartridge	I-Protocol
slots	O
,	O
an	O
analogue	O
interface	O
(	O
supporting	O
four	O
channels	O
)	O
and	O
a	O
Centronics	O
parallel	O
port	O
,	O
priced	O
at	O
£59.90	O
.	O
</s>
<s>
Game	O
ROM	B-Protocol
cartridges	I-Protocol
would	O
boot	O
automatically	O
.	O
</s>
<s>
Languages	O
in	O
paged	O
ROM	B-Protocol
cartridges	I-Protocol
would	O
take	O
precedence	O
over	O
BASIC	O
.	O
</s>
<s>
Access	O
to	O
ROM	B-Device
occurred	O
at	O
2MHz	O
until	O
RAM	B-Architecture
access	O
was	O
required	O
,	O
so	O
theoretically	O
programs	O
released	O
on	O
ROM	B-Device
could	O
run	O
up	O
to	O
twice	O
as	O
fast	O
as	O
those	O
released	O
on	O
tape	O
or	O
disc	O
.	O
</s>
<s>
Despite	O
this	O
,	O
all	O
of	O
the	O
games	O
released	O
on	O
ROM	B-Device
were	O
packaged	O
as	O
ROM	B-Device
filing	O
system	O
cartridges	B-Protocol
,	O
from	O
which	O
the	O
micro	O
would	O
load	O
programs	O
into	O
main	O
memory	O
in	O
exactly	O
the	O
same	O
way	O
as	O
if	O
it	O
were	O
loading	O
from	O
tape	O
.	O
</s>
<s>
Six	O
ROM	B-Protocol
cartridge	I-Protocol
titles	O
were	O
announced	O
for	O
the	O
launch	O
of	O
the	O
Plus	O
1	O
:	O
three	O
arcade	O
games	O
,	O
one	O
adventure	O
game	O
,	O
one	O
educational	O
title	O
,	O
and	O
the	O
Lisp	B-Language
language	I-Language
implementation	O
,	O
the	O
latter	O
being	O
a	O
genuine	O
language	O
ROM	B-Device
that	O
"	O
takes	O
the	O
place	O
of	O
the	O
BASIC	O
ROM	B-Device
"	O
and	O
is	O
instantly	O
available	O
when	O
switching	O
on	O
.	O
</s>
<s>
The	O
cartridge	B-Protocol
slots	O
provided	O
additional	O
control	O
lines	O
(	O
compared	O
to	O
the	O
lines	O
available	O
via	O
the	O
edge	O
connector	O
on	O
the	O
rear	O
of	O
the	O
Electron	O
)	O
to	O
ease	O
implementation	O
of	O
ROM	B-Protocol
cartridges	I-Protocol
.	O
</s>
<s>
Acorn	O
described	O
the	O
hardware	O
extension	O
possibilities	O
in	O
promotional	O
literature	O
,	O
giving	O
an	O
RS423	O
cartridge	B-Protocol
as	O
an	O
example	O
of	O
this	O
capability	O
of	O
the	O
Plus	O
1	O
.	O
</s>
<s>
Additional	O
peripheral	O
cartridges	B-Protocol
were	O
produced	O
by	O
companies	O
such	O
as	O
Advanced	O
Computer	O
Products	O
(	O
and	O
subsequently	O
PRES	O
)	O
whose	O
Advanced	O
ROM	B-Device
Adaptor	O
(	O
ARA	O
)	O
and	O
Advanced	O
Sideways	B-General_Concept
RAM	I-General_Concept
(	O
ASR	O
)	O
products	O
provided	O
sideways	B-General_Concept
ROM	I-General_Concept
and	I-General_Concept
RAM	I-General_Concept
capabilities	O
,	O
allowing	O
ROM	B-Device
-	O
or	O
EPROM-based	O
software	O
to	O
be	O
accessed	O
to	O
provide	O
languages	O
,	O
utilities	O
and	O
applications	O
.	O
</s>
<s>
ROM	B-Device
or	O
EPROM	O
devices	O
containing	O
the	O
software	O
could	O
be	O
physically	O
inserted	O
into	O
empty	O
ZIF	B-General_Concept
sockets	I-General_Concept
,	O
or	O
the	O
software	O
would	O
be	O
loaded	O
from	O
ROM	B-Device
image	O
files	O
(	O
typically	O
provided	O
on	O
disk	O
)	O
into	O
RAM	B-Architecture
devices	O
fitted	O
in	O
such	O
sockets	O
.	O
</s>
<s>
Such	O
RAM	B-Architecture
could	O
potentially	O
be	O
powered	O
by	O
a	O
battery	O
and	O
thus	O
be	O
able	O
to	O
retain	O
its	O
contents	O
when	O
the	O
computer	O
itself	O
was	O
powered	O
off	O
.	O
</s>
<s>
Such	O
cartridge	B-Protocol
support	O
enabled	O
the	O
Electron	O
to	O
provide	O
the	O
same	O
functionality	O
as	O
that	O
offered	O
by	O
the	O
expansion	O
ROM	B-Device
slots	O
under	O
the	O
keyboard	B-Device
and	O
on	O
the	O
bottom-left	O
of	O
the	O
BBC	B-Device
Micro	I-Device
B	O
keyboard	B-Device
.	O
</s>
<s>
However	O
,	O
the	O
need	O
to	O
use	O
cartridge	B-Protocol
sockets	O
for	O
other	O
peripherals	O
encouraged	O
PRES	O
to	O
develop	O
the	O
Advanced	O
Plus	O
6	O
(	O
AP6	O
)	O
:	O
an	O
internal	O
RAM	B-Architecture
and	O
ROM	B-Device
board	O
for	O
the	O
Plus	O
1	O
providing	O
six	O
sockets	O
that	O
could	O
be	O
freely	O
used	O
for	O
ROM	B-Device
,	O
EPROM	O
and	O
RAM	B-Architecture
devices	O
.	O
</s>
<s>
Installation	O
of	O
the	O
AP6	O
unit	O
required	O
some	O
modifications	O
to	O
the	O
Plus	O
1	O
,	O
undertaken	O
either	O
by	O
the	O
user	O
or	O
by	O
PRES	O
,	O
and	O
the	O
product	O
could	O
also	O
be	O
enhanced	O
with	O
the	O
Advanced	O
Plus	O
7	O
offering	O
battery-backed	O
RAM	B-Architecture
support	O
for	O
two	O
16KB	O
banks	O
.	O
</s>
<s>
An	O
official	O
application	O
note	O
described	O
a	O
similar	O
set	O
of	O
commands	O
to	O
"	O
remove	O
the	O
Plus	O
One	O
completely	O
from	O
the	O
address	O
map	O
disabling	O
the	O
Centronics	O
and	O
A/D	O
ports	O
(	O
additionally	O
disabling	O
the	O
RS423	O
cartridge	B-Protocol
if	O
fitted	O
)	O
"	O
.	O
</s>
<s>
The	O
Advanced	O
Plus	O
2	O
(	O
AP2	O
)	O
ROM	B-Device
was	O
later	O
sold	O
by	O
PRES	O
as	O
a	O
replacement	O
ROM	B-Device
for	O
the	O
Plus	O
1	O
,	O
of	O
whose	O
8KB	O
utility	O
ROM	B-Device
only	O
3KB	O
had	O
been	O
used	O
,	O
thus	O
providing	O
an	O
opportunity	O
for	O
a	O
more	O
comprehensive	O
ROM	B-Device
to	O
be	O
developed	O
.	O
</s>
<s>
The	O
AP2	O
added	O
ROM	B-Device
management	O
commands	O
familiar	O
from	O
the	O
BBC	B-Device
Master	I-Device
series	I-Device
,	O
support	O
for	O
various	O
sideways	B-General_Concept
RAM	I-General_Concept
products	O
from	O
PRES	O
,	O
disc	O
formatting	O
and	O
verification	O
utilities	O
for	O
different	O
ADFS	O
versions	O
,	O
a	O
command	O
to	O
disable	O
the	O
Plus	O
1	O
entirely	O
,	O
and	O
improvements	O
that	O
made	O
tape	O
loading	O
more	O
reliable	O
in	O
"	O
high	O
memory	O
"	O
screen	O
modes	O
.	O
</s>
<s>
Following	O
on	O
from	O
Slogger	O
's	O
earlier	O
Rombox	O
product	O
an	O
expansion	O
similar	O
in	O
profile	O
to	O
the	O
Plus	O
1	O
but	O
offering	O
eight	O
ROM	B-Device
sockets	O
and	O
propagating	O
the	O
expansion	O
connector	O
to	O
other	O
units	O
the	O
Rombox	O
Plus	O
was	O
positioned	O
more	O
directly	O
as	O
a	O
competitor	O
to	O
the	O
Plus	O
1	O
in	O
that	O
it	O
offered	O
two	O
cartridge	B-Protocol
slots	O
and	O
a	O
Centronics	O
print	O
port	O
alongside	O
four	O
ROM	B-Device
sockets	O
.	O
</s>
<s>
Priced	O
at	O
£49.95	O
,	O
the	O
unit	O
was	O
mostly	O
compatible	O
with	O
cartridges	B-Protocol
designed	O
for	O
the	O
Plus	O
1	O
although	O
one	O
reviewer	O
reported	O
physical	O
issues	O
with	O
some	O
expansion	O
cartridges	B-Protocol
,	O
suggesting	O
some	O
manufacturing	O
inconsistencies	O
given	O
other	O
users	O
 '	O
more	O
positive	O
experiences	O
,	O
but	O
indicated	O
that	O
it	O
was	O
still	O
"	O
worth	O
considering	O
as	O
an	O
alternative	O
to	O
the	O
Plus	O
1	O
"	O
.	O
</s>
<s>
One	O
review	O
reported	O
that	O
the	O
Cumana	O
Electron	O
Filing	O
System	O
cartridge	B-Protocol
had	O
an	O
edge	O
connector	O
that	O
would	O
not	O
physically	O
fit	O
inside	O
the	O
slot	O
in	O
the	O
Rombox	O
Plus	O
unit	O
;	O
this	O
along	O
with	O
a	O
perceived	O
lack	O
of	O
robustness	O
of	O
the	O
case	O
being	O
their	O
only	O
major	O
reservations	O
about	O
the	O
product	O
.	O
</s>
<s>
The	O
product	O
's	O
support	O
for	O
utilising	O
8KB	O
RAM	B-Architecture
devices	O
as	O
a	O
printer	O
buffer	O
,	O
with	O
buffer	O
management	O
provided	O
by	O
the	O
built-in	O
EPROM	O
,	O
was	O
noted	O
as	O
a	O
particular	O
advantage	O
over	O
the	O
Plus	O
1	O
.	O
</s>
<s>
Intended	O
for	O
the	O
RX	O
system	O
,	O
the	O
Plus	O
2	O
offered	O
two	O
ROM	B-Protocol
cartridge	I-Protocol
slots	O
compatible	O
with	O
the	O
Plus	O
1	O
,	O
three	O
ROM	B-Device
sockets	O
,	O
and	O
RS423	O
and	O
user	O
port	O
capabilities	O
.	O
</s>
<s>
In	O
mid-1989	O
,	O
Software	O
Bargains	O
announced	O
an	O
expansion	O
providing	O
different	O
levels	O
of	O
Plus	O
1	O
functionality	O
,	O
offered	O
as	O
a	O
bare	O
printed	O
circuit	O
board	O
without	O
casing	O
and	O
in	O
three	O
different	O
variants	O
:	O
the	O
basic	O
model	O
offered	O
one	O
cartridge	B-Protocol
port	O
and	O
was	O
bundled	O
with	O
View	O
and	O
Viewsheet	O
cartridges	B-Protocol
for	O
£29.95	O
;	O
an	O
extended	O
model	O
offered	O
one	O
cartridge	B-Protocol
port	O
and	O
a	O
printer	O
port	O
with	O
the	O
two	O
bundled	O
cartridges	B-Protocol
for	O
£36.95	O
;	O
the	O
full	O
model	O
offered	O
two	O
cartridge	B-Protocol
ports	O
,	O
printer	O
port	O
and	O
the	O
bundled	O
cartridges	B-Protocol
for	O
£39.95	O
.	O
</s>
<s>
To	O
support	O
connectivity	O
,	O
Acorn	O
announced	O
a	O
Plus	O
2	O
network	O
interface	O
with	O
availability	O
scheduled	O
for	O
early	O
1985	O
,	O
together	O
with	O
a	O
RS423	O
cartridge	B-Protocol
for	O
the	O
Plus	O
1	O
.	O
</s>
<s>
The	O
Acorn	O
Plus	O
2	O
interface	O
was	O
due	O
to	O
provide	O
Econet	B-Device
capability	O
.	O
</s>
<s>
However	O
,	O
an	O
Econet	B-Device
interface	O
was	O
produced	O
by	O
Barson	O
Computers	O
in	O
Australia	O
and	O
possibly	O
other	O
individuals	O
and	O
businesses	O
.	O
</s>
<s>
The	O
Acorn	O
Plus	O
4	O
interface	O
was	O
due	O
to	O
provide	O
a	O
modem	B-Application
communications	O
capability	O
.	O
</s>
<s>
Andyk	O
announced	O
an	O
RS423	O
cartridge	B-Protocol
for	O
the	O
Plus	O
1	O
providing	O
a	O
serial	O
port	O
,	O
alongside	O
other	O
products	O
,	O
in	O
late	O
1985	O
.	O
</s>
<s>
Originally	O
reported	O
in	O
mid-1985	O
as	O
a	O
collaboration	O
between	O
Acorn	O
and	O
Pace	O
Micro	O
Technology	O
,	O
but	O
launched	O
in	O
early	O
1986	O
,	O
Pace	O
offered	O
a	O
communications	O
product	O
consisting	O
of	O
a	O
RS423	O
cartridge	B-Protocol
,	O
bundled	O
with	O
a	O
Nightingale	O
modem	B-Application
and	O
Tellstar	O
communications	O
software	O
,	O
offered	O
at	O
a	O
discounted	O
price	O
of	O
£145	O
.	O
</s>
<s>
Jafa	O
Systems	O
announced	O
an	O
RS423	O
cartridge	B-Protocol
in	O
late	O
1989	O
to	O
"	O
fill	O
a	O
two	O
year	O
gap	O
in	O
the	O
market	O
"	O
,	O
offering	O
a	O
serial	O
connector	O
compatible	O
with	O
the	O
BBC	B-Device
Micro	I-Device
together	O
with	O
an	O
on-board	O
socket	O
for	O
8KB	O
or	O
16KB	O
EPROM	O
devices	O
or	O
for	O
32KB	O
RAM	B-Architecture
,	O
the	O
latter	O
being	O
configured	O
to	O
present	O
two	O
sideways	B-General_Concept
RAM	I-General_Concept
banks	O
to	O
the	O
system	O
.	O
</s>
<s>
Write	O
protect	O
functionality	O
was	O
supported	O
to	O
prevent	O
certain	O
ROM	B-Device
software	O
from	O
attempting	O
to	O
overwrite	O
itself	O
if	O
stored	O
in	O
RAM	B-Architecture
.	O
</s>
<s>
The	O
cartridge	B-Protocol
board	O
itself	O
was	O
priced	O
at	O
around	O
£30	O
,	O
with	O
a	O
case	O
costing	O
£5	O
extra	O
,	O
and	O
an	O
optional	O
32KB	O
RAM	B-Architecture
adding	O
another	O
£20	O
.	O
</s>
<s>
Support	O
for	O
the	O
E00	O
ADFS	O
offered	O
by	O
PRES	O
for	O
that	O
company	O
's	O
AP3	O
disc	O
system	O
was	O
indicated	O
as	O
an	O
application	O
for	O
the	O
sideways	B-General_Concept
RAM	I-General_Concept
.	O
</s>
<s>
The	O
first	O
disc	O
interface	O
to	O
be	O
announced	O
for	O
the	O
Electron	O
was	O
Pace	O
's	O
Le	O
Box	O
in	O
1984	O
,	O
offering	O
a	O
single-sided	O
100KB	O
floppy	B-Device
drive	I-Device
controlled	O
by	O
the	O
8271	O
controller	O
and	O
accessed	O
using	O
the	O
Amcom	O
Disc	B-Application
Filing	I-Application
System	I-Application
,	O
with	O
pricing	O
at	O
£299	O
plus	O
VAT	O
including	O
the	O
drive	O
or	O
around	O
£199	O
without	O
.	O
</s>
<s>
The	O
unit	O
also	O
provided	O
eight	O
sideways	O
ROM	B-Device
sockets	O
and	O
was	O
intended	O
to	O
sit	O
under	O
the	O
Electron	O
itself	O
.	O
</s>
<s>
Unlike	O
disc	O
systems	O
on	O
the	O
BBC	B-Device
Micro	I-Device
and	O
the	O
Acorn	O
Plus	O
3	O
,	O
many	O
of	O
the	O
systems	O
released	O
for	O
the	O
Electron	O
did	O
not	O
claim	O
RAM	B-Architecture
workspace	O
(	O
and	O
raise	O
the	O
PAGE	O
variable	O
affecting	O
applications	O
above	O
the	O
default	O
of	O
&	O
E00	O
)	O
,	O
making	O
it	O
easier	O
to	O
use	O
cassette-based	O
software	O
transferred	O
to	O
disc	O
and	O
to	O
run	O
larger	O
programs	O
from	O
disc	O
.	O
</s>
<s>
Low-cost	O
alternatives	O
to	O
disc	O
systems	O
,	O
briefly	O
made	O
fashionable	O
by	O
press	O
coverage	O
of	O
the	O
Sinclair	B-Device
Microdrive	I-Device
,	O
were	O
reportedly	O
under	O
development	O
by	O
expansion	O
suppliers	O
such	O
as	O
Solidisk	O
,	O
and	O
finished	O
products	O
such	O
as	O
the	O
Phloopy	O
looped	O
tape	O
system	O
were	O
offered	O
for	O
the	O
Electron	O
.	O
</s>
<s>
Launched	O
in	O
late	O
1984	O
for	O
a	O
price	O
of	O
£229	O
,	O
the	O
Acorn	O
Plus	O
3	O
was	O
a	O
hardware	O
module	O
that	O
connected	O
independently	O
of	O
the	O
Plus	O
1	O
and	O
provided	O
a	O
"	O
self	O
contained	O
disc	O
interface	O
and	O
3.5	O
inch	O
single	O
sided	O
disc	O
drive	O
"	O
offering	O
over	O
300KB	O
of	O
storage	O
per	O
disc	O
using	O
the	O
newly	O
introduced	O
Advanced	B-Device
Disc	I-Device
Filing	I-Device
System	I-Device
(	O
ADFS	O
)	O
.	O
</s>
<s>
An	O
expansion	O
connector	O
for	O
a	O
second	O
3.5	O
-	O
or	O
5.25-inch	O
drive	O
was	O
also	O
provided	O
by	O
the	O
unit	O
,	O
with	O
such	O
drives	O
needing	O
to	O
provide	O
a	O
Shugart-compatible	O
connector	O
and	O
their	O
own	O
power	O
supply	O
.	O
</s>
<s>
The	O
double-density	O
drive	O
of	O
the	O
Plus	O
3	O
was	O
driven	O
using	O
a	O
WD1770	B-Device
drive	B-General_Concept
controller	I-General_Concept
by	O
the	O
ADFS	O
.	O
</s>
<s>
(	O
The	O
Plus	O
3	O
had	O
been	O
rumoured	O
to	O
offer	O
Acorn	O
's	O
DFS	O
and	O
to	O
feature	O
a	O
8272	O
double-density	O
disk	B-General_Concept
controller	I-General_Concept
before	O
its	O
launch	O
.	O
)	O
</s>
<s>
Because	O
the	O
WD1770	B-Device
is	O
capable	O
of	O
single-density	O
mode	O
and	O
uses	O
the	O
same	O
IBM360-derived	O
floppy	B-Device
disc	I-Device
format	O
as	O
the	O
Intel	O
8271	O
found	O
in	O
the	O
BBC	B-Device
Micro	I-Device
,	O
it	O
was	O
also	O
possible	O
to	O
use	O
the	O
Disc	B-Application
Filing	I-Application
System	I-Application
with	O
an	O
alternate	O
ROM	B-Device
,	O
such	O
as	O
the	O
ACP	O
1770	O
DFS	O
.	O
</s>
<s>
The	O
Plus	O
3	O
reset	O
PAGE	O
to	O
&	O
1D00	O
,	O
reducing	O
the	O
amount	O
of	O
free	O
RAM	B-Architecture
available	O
to	O
the	O
user	O
.	O
</s>
<s>
This	O
behaviour	O
was	O
the	O
same	O
as	O
on	O
the	O
BBC	B-Device
Micro	I-Device
.	O
</s>
<s>
Designed	O
and	O
produced	O
by	O
Baildon	O
Electronics	O
and	O
sold	O
by	O
PRES	O
,	O
the	O
Advanced	O
Plus	O
3	O
(	O
AP3	O
)	O
was	O
a	O
Plus	O
1	O
cartridge	B-Protocol
interface	O
using	O
the	O
WD1770	B-Device
controller	O
,	O
supplied	O
with	O
Acorn	O
's	O
ADFS	O
and	O
a	O
single-sided	O
3½-inch	O
disc	O
drive	O
for	O
£99	O
plus	O
VAT	O
,	O
offering	O
equivalent	O
functionality	O
to	O
the	O
Acorn	O
Plus	O
3	O
.	O
</s>
<s>
As	O
with	O
many	O
disc	O
interfaces	O
for	O
the	O
Electron	O
,	O
since	O
the	O
interface	O
provided	O
a	O
connector	O
for	O
the	O
drive	O
,	O
this	O
made	O
it	O
possible	O
to	O
connect	O
a	O
5¼	O
"	O
floppy	B-Device
disc	I-Device
drive	I-Device
(	O
more	O
common	O
amongst	O
BBC	B-Device
Micro	I-Device
owners	O
)	O
or	O
the	O
more	O
typical	O
3½-inch	O
drive	O
.	O
</s>
<s>
PRES	O
later	O
released	O
a	O
version	O
of	O
ADFS	O
with	O
support	O
for	O
PAGE	O
at	O
&	O
E00	O
,	O
this	O
being	O
achieved	O
by	O
using	O
RAM	B-Architecture
provided	O
by	O
the	O
Advanced	O
Battery	O
Backed	O
RAM	B-Architecture
(	O
ABR	O
)	O
cartridge	B-Protocol
.	O
</s>
<s>
The	O
ROM	B-Device
image	O
was	O
supplied	O
on	O
disc	O
for	O
£17.19	O
,	O
whereas	O
a	O
bundle	O
of	O
the	O
ROM	B-Device
and	O
ABR	O
cartridge	B-Protocol
was	O
£50.95	O
.	O
</s>
<s>
Early	O
in	O
1985	O
,	O
Cumana	O
released	O
a	O
cartridge-based	O
interface	O
providing	O
support	O
for	O
double-density	O
storage	O
,	O
a	O
real-time	O
clock	O
and	O
calendar	O
for	O
timestamping	O
of	O
files	O
,	O
and	O
a	O
spare	O
ROM	B-Device
socket	O
for	O
user-fitted	O
sideways	O
ROMs	O
.	O
</s>
<s>
In	O
mid-1985	O
,	O
Solidisk	O
released	O
a	O
cartridge-based	O
interface	O
with	O
support	O
for	O
single	O
and	O
double	O
density	O
storage	O
and	O
providing	O
Acorn	B-Application
DFS	I-Application
and	O
ADFS	O
compatibility	O
,	O
16KB	O
of	O
on-board	O
sideways	B-General_Concept
RAM	I-General_Concept
,	O
and	O
a	O
connector	O
for	O
a	O
Winchester	O
hard	O
drive	O
.	O
</s>
<s>
The	O
cartridge	B-Protocol
itself	O
cost	O
£59	O
,	O
with	O
a	O
bundle	O
including	O
a	O
double-sided	O
,	O
double-density	O
,	O
3½-inch	O
drive	O
costing	O
£200	O
.	O
</s>
<s>
Announced	O
in	O
early	O
1986	O
,	O
the	O
Advanced	O
Plus	O
4	O
(	O
AP4	O
)	O
from	O
Advanced	O
Computer	O
Products	O
was	O
a	O
cartridge-based	O
interface	O
employing	O
the	O
WD1770	B-Device
controller	O
and	O
featuring	O
ACP	O
's	O
1770	O
DFS	O
product	O
,	O
providing	O
compatibility	O
with	O
Acorn	O
's	O
DFS	O
from	O
the	O
BBC	B-Device
Micro	I-Device
and	O
thereby	O
supporting	O
seven-character	O
filenames	O
and	O
up	O
to	O
31	O
files	O
per	O
disc	O
.	O
</s>
<s>
However	O
,	O
8KB	O
of	O
on-board	O
static	O
RAM	B-Architecture
was	O
used	O
as	O
workspace	O
for	O
the	O
filing	O
system	O
,	O
keeping	O
PAGE	O
at	O
&	O
E00	O
.	O
</s>
<s>
An	O
extra	O
ROM	B-Device
socket	O
was	O
provided	O
for	O
a	O
user-fitted	O
sideways	O
ROM	B-Device
,	O
and	O
being	O
a	O
1770-based	O
interface	O
,	O
it	O
was	O
reported	O
that	O
Acorn	O
's	O
ADFS	O
could	O
be	O
used	O
instead	O
,	O
although	O
since	O
it	O
was	O
not	O
aware	O
of	O
the	O
additional	O
RAM	B-Architecture
,	O
PAGE	O
would	O
be	O
raised	O
to	O
&	O
1D00	O
as	O
it	O
would	O
be	O
when	O
using	O
Acorn	O
's	O
Plus	O
3	O
.	O
</s>
<s>
Slogger	O
,	O
an	O
established	O
producer	O
of	O
expansions	O
and	O
a	O
reseller	O
of	O
other	O
disc	O
systems	O
,	O
introduced	O
the	O
Electron	O
Disc	O
System	O
in	O
early	O
1987	O
,	O
priced	O
at	O
£74.95	O
,	O
featuring	O
the	O
Cumana	O
Floppy	B-Device
Disc	I-Device
System	O
interface	O
,	O
which	O
was	O
combined	O
with	O
an	O
Acorn-compatible	O
DFS	O
,	O
SEDFS	O
,	O
having	O
the	O
capability	O
of	O
reading	O
40-track	O
discs	O
on	O
80-track	O
drives	O
plus	O
support	O
for	O
Slogger	O
's	O
tape-to-disc	O
conversion	O
products	O
,	O
and	O
reported	O
as	O
offering	O
"	O
virtual	O
100	O
per	O
cent	O
8271	O
emulation	O
"	O
for	O
compatibility	O
with	O
traditional	O
DFS	O
software	O
.	O
</s>
<s>
The	O
SEDFS	O
ROM	B-Device
was	O
also	O
available	O
separately	O
for	O
existing	O
Cumana	O
interface	O
owners	O
,	O
priced	O
at	O
£24.95	O
.	O
</s>
<s>
The	O
SEDFS	O
was	O
later	O
bundled	O
with	O
Slogger	O
's	O
own	O
cartridge-based	O
interface	O
and	O
a	O
40/80	O
-track	O
switchable	O
drive	O
offering	O
up	O
to	O
400KB	O
storage	O
per	O
disc	O
,	O
with	O
the	O
bundle	O
taking	O
the	O
Pegasus	O
400	O
name	O
,	O
introduced	O
as	O
part	O
of	O
a	O
sales	O
tour	O
towards	O
the	O
end	O
of	O
1987	O
.	O
</s>
<s>
The	O
precise	O
DFS	O
variant	O
used	O
by	O
the	O
Pegasus	O
400	O
system	O
kept	O
PAGE	O
at	O
&	O
E00	O
and	O
introduced	O
"	O
typeahead	O
"	O
support	O
,	O
permitting	O
keystroke	O
buffering	O
during	O
disc	O
activity	O
on	O
systems	O
with	O
the	O
Turbo-Driver	O
or	O
Master	O
RAM	B-Architecture
Board	O
fitted	O
and	O
enabled	O
.	O
</s>
<s>
The	O
board	O
itself	O
plugged	O
into	O
the	O
CPU	B-General_Concept
and	O
BASIC	O
ROM	B-Device
sockets	O
on	O
the	O
main	O
circuit	O
board	O
of	O
the	O
Electron	O
,	O
which	O
merely	O
involved	O
removing	O
socketed	O
components	O
on	O
very	O
early	O
Electron	O
models	O
,	O
but	O
required	O
desoldering	O
work	O
and	O
therefore	O
benefited	O
from	O
a	O
fitting	O
service	O
for	O
later	O
units	O
.	O
</s>
<s>
By	O
shadowing	O
the	O
lowest	O
8KB	O
of	O
RAM	B-Architecture
with	O
a	O
static	O
RAM	B-Architecture
chip	I-Architecture
outside	O
of	O
reach	O
of	O
the	O
ULA	O
,	O
the	O
CPU	B-General_Concept
could	O
always	O
access	O
it	O
at	O
2MHz	O
.	O
</s>
<s>
In	O
practice	O
the	O
operating	B-Operating_System
system	I-Operating_System
ROMs	O
always	O
put	O
the	O
screen	O
into	O
the	O
top	O
20KB	O
and	O
as	O
a	O
result	O
this	O
probably	O
only	O
broke	O
compatibility	O
with	O
around	O
2%	O
of	O
software	O
.	O
</s>
<s>
Speeding	O
up	O
the	O
low	O
portion	O
of	O
memory	O
is	O
particularly	O
useful	O
on	O
6502	B-General_Concept
derived	O
machines	O
because	O
that	O
processor	O
has	O
a	O
faster	O
addressing	B-General_Concept
for	I-General_Concept
the	I-General_Concept
first	I-General_Concept
256	I-General_Concept
bytes	I-General_Concept
and	O
so	O
it	O
is	O
common	O
for	O
software	O
to	O
put	O
any	O
variables	O
involved	O
in	O
time-critical	O
sections	O
of	O
program	O
into	O
that	O
region	O
.	O
</s>
<s>
The	O
cost	O
of	O
the	O
64	O
Kbit	O
SRAM	O
chip	O
would	O
have	O
been	O
more	O
than	O
that	O
of	O
doubling	O
the	O
four	O
64	O
Kbit	O
DRAM	O
chips	O
to	O
give	O
8-bit	O
RAM	B-Architecture
access	O
,	O
fixing	O
both	O
the	O
modest	O
memory	O
and	O
poor	O
performance	O
issues	O
of	O
the	O
Electron	O
.	O
</s>
<s>
Introduced	O
at	O
around	O
the	O
start	O
of	O
1987	O
and	O
priced	O
at	O
£64.95	O
fitted	O
or	O
£54.95	O
as	O
a	O
kit	O
,	O
the	O
Master	O
RAM	B-Architecture
Board	O
offered	O
the	O
familiar	O
turbo	O
mode	O
from	O
the	O
Slogger	O
Turbo-Driver	O
alongside	O
a	O
shadow	O
mode	O
providing	O
32KB	O
of	O
static	O
shadow	B-General_Concept
RAM	I-General_Concept
in	O
addition	O
to	O
the	O
existing	O
32KB	O
,	O
thus	O
giving	O
64KB	O
in	O
total	O
.	O
</s>
<s>
So-called	O
"	O
legally	O
written	O
software	O
"	O
,	O
this	O
being	O
software	O
using	O
the	O
operating	B-Operating_System
system	I-Operating_System
calls	O
and	O
not	O
writing	O
directly	O
to	O
the	O
screen	O
,	O
could	O
function	O
without	O
significant	O
modification	O
,	O
making	O
substantially	O
more	O
memory	O
available	O
for	O
BASIC	O
,	O
View	O
,	O
Viewsheet	O
,	O
language	O
ROMs	O
and	O
many	O
other	O
applications	O
.	O
</s>
<s>
By	O
providing	O
extra	O
storage	O
this	O
modification	O
also	O
allowed	O
some	O
games	O
and	O
applications	O
intended	O
for	O
the	O
BBC	B-Device
Micro	I-Device
to	O
function	O
on	O
the	O
Electron	O
despite	O
the	O
lack	O
of	O
a	O
native	O
Mode	O
7	O
.	O
</s>
<s>
Towards	O
the	O
end	O
of	O
the	O
Electron	O
's	O
commercial	O
lifetime	O
,	O
the	O
Turbo-Driver	O
and	O
Master	O
RAM	B-Architecture
Boards	O
were	O
offered	O
already	O
fitted	O
to	O
new	O
Electrons	O
in	O
an	O
attempt	O
to	O
increase	O
sales	O
.	O
</s>
<s>
For	O
a	O
time	O
,	O
Jafa	O
Systems	O
manufactured	O
their	O
own	O
equivalent	O
of	O
the	O
Master	O
RAM	B-Architecture
Board	O
in	O
order	O
to	O
support	O
their	O
own	O
product	O
range	O
.	O
</s>
<s>
One	O
of	O
the	O
features	O
of	O
the	O
BBC	B-Device
Micro	I-Device
that	O
was	O
absent	O
in	O
the	O
Electron	O
was	O
the	O
Teletext-style	O
Mode	O
7	O
display	O
.	O
</s>
<s>
Such	O
display	O
capabilities	O
,	O
desirable	O
in	O
their	O
own	O
right	O
on	O
low-memory	O
computers	O
,	O
were	O
also	O
desirable	O
for	O
delivering	O
content	O
through	O
low-bandwidth	O
communications	O
channels	O
such	O
as	O
that	O
from	O
Teletext	O
and	O
Viewdata	B-Application
services	O
.	O
</s>
<s>
However	O
,	O
access	O
to	O
such	O
services	O
can	O
be	O
considered	O
to	O
be	O
a	O
separate	O
capability	O
,	O
and	O
the	O
BBC	B-Device
Micro	I-Device
needed	O
to	O
be	O
upgraded	O
to	O
complement	O
its	O
display	O
capability	O
with	O
the	O
Teletext	O
or	O
Prestel	B-General_Concept
adapters	O
to	O
receive	O
such	O
over-the-air	O
or	O
online	O
content	O
.	O
</s>
<s>
Released	O
in	O
1987	O
at	O
a	O
price	O
of	O
£89	O
,	O
the	O
Mode	O
7	O
Mark	O
1	O
Display	O
Unit	O
was	O
a	O
separate	O
unit	O
"	O
about	O
the	O
size	O
,	O
shape	O
and	O
colour	O
of	O
the	O
Plus	O
One	O
or	O
a	O
Slogger	O
ROMbox	O
"	O
that	O
connected	O
to	O
the	O
Electron	O
's	O
expansion	O
connector	O
and	O
featured	O
a	O
Motorola	B-General_Concept
6845	I-General_Concept
display	O
controller	O
and	O
Mullard	B-General_Concept
SAA5050	I-General_Concept
character	O
generator	O
to	O
replicate	O
the	O
main	O
elements	O
of	O
the	O
BBC	B-Device
Micro	I-Device
's	O
Teletext	O
display	O
solution	O
.	O
</s>
<s>
A	O
ROM	B-Device
was	O
included	O
to	O
extend	O
the	O
operating	B-Operating_System
system	I-Operating_System
to	O
allow	O
activation	O
of	O
Mode	O
7	O
as	O
a	O
genuine	O
screen	O
mode	O
and	O
to	O
provide	O
extra	O
commands	O
and	O
to	O
support	O
keyboard	B-Device
shortcuts	O
used	O
on	O
the	O
BBC	B-Device
Micro	I-Device
to	O
emit	O
Teletext	O
control	O
sequences	O
.	O
</s>
<s>
Conscious	O
of	O
the	O
relatively	O
high	O
price	O
of	O
the	O
Mark	O
1	O
unit	O
,	O
John	O
Wike	O
of	O
Jafa	O
devised	O
and	O
,	O
at	O
the	O
end	O
of	O
1988	O
,	O
introduced	O
a	O
software-based	O
Mode	O
7	O
Simulator	O
,	O
priced	O
at	O
£25	O
,	O
supplied	O
on	O
a	O
ROM	B-Protocol
cartridge	I-Protocol
that	O
rendered	O
the	O
Mode	O
7	O
display	O
in	O
a	O
low-resolution	O
,	O
8-colour	O
graphics	O
mode	O
.	O
</s>
<s>
Although	O
cheap	O
and	O
effective	O
in	O
enabling	O
use	O
of	O
some	O
software	O
that	O
only	O
used	O
official	O
operating	B-Operating_System
system	I-Operating_System
routines	O
for	O
text	O
output	O
,	O
this	O
solution	O
proved	O
very	O
slow	O
because	O
the	O
Electron	O
had	O
to	O
be	O
placed	O
into	O
the	O
high-bandwidth	O
Mode	O
2	O
display	O
to	O
be	O
able	O
to	O
show	O
eight	O
colours	O
at	O
once	O
.	O
</s>
<s>
In	O
doing	O
so	O
,	O
the	O
CPU	B-General_Concept
spent	O
a	O
lot	O
of	O
time	O
drawing	O
representations	O
of	O
Mode	O
7	O
characters	O
and	O
graphics	O
that	O
in	O
a	O
hardware	O
solution	O
would	O
be	O
achieved	O
without	O
any	O
demand	O
on	O
the	O
CPU	B-General_Concept
.	O
</s>
<s>
It	O
also	O
used	O
up	O
20KB	O
of	O
RAM	B-Architecture
for	O
the	O
graphics	O
display	O
rather	O
than	O
the	O
1000	O
bytes	O
of	O
a	O
hardware	O
Mode	O
7	O
.	O
</s>
<s>
A	O
further	O
refinement	O
of	O
the	O
hardware	O
solution	O
was	O
introduced	O
in	O
1989	O
with	O
the	O
Mode	O
7	O
Mark	O
2	O
Display	O
Unit	O
,	O
which	O
retained	O
the	O
SAA5050	B-General_Concept
character	O
generator	O
but	O
omitted	O
the	O
6845	B-General_Concept
display	O
controller	O
,	O
and	O
was	O
fitted	O
internally	O
in	O
the	O
Electron	O
itself	O
instead	O
of	O
being	O
housed	O
in	O
an	O
external	O
unit	O
,	O
although	O
some	O
kind	O
of	O
ROM	B-Device
expansion	O
unit	O
was	O
needed	O
to	O
hold	O
the	O
driver/utilities	O
ROM	B-Device
.	O
</s>
<s>
It	O
used	O
software	O
to	O
ensure	O
that	O
the	O
SAA5050	B-General_Concept
was	O
fed	O
with	O
the	O
correct	O
character	O
data	O
.	O
</s>
<s>
A	O
software	O
ROM	B-Device
would	O
put	O
the	O
machine	O
into	O
a	O
two-colour	O
,	O
40-column	O
graphics	O
mode	O
(	O
thus	O
providing	O
one	O
byte	O
per	O
character	O
)	O
,	O
and	O
as	O
the	O
ULA	O
read	O
display	O
data	O
from	O
memory	O
in	O
the	O
usual	O
fashion	O
,	O
the	O
SAA5050	B-General_Concept
would	O
listen	O
to	O
the	O
data	O
it	O
was	O
reading	O
and	O
produce	O
a	O
Mode	O
7	O
interpretation	O
of	O
the	O
same	O
information	O
,	O
this	O
being	O
achieved	O
by	O
fitting	O
a	O
board	O
on	O
top	O
of	O
the	O
ULA	O
connecting	O
to	O
its	O
pins	O
.	O
</s>
<s>
The	O
disadvantage	O
to	O
this	O
system	O
is	O
that	O
while	O
the	O
SAA5050	B-General_Concept
would	O
expect	O
to	O
be	O
repeatedly	O
fed	O
the	O
same	O
40	O
bytes	O
of	O
data	O
for	O
every	O
display	O
scanline	O
of	O
each	O
character	O
row	O
,	O
the	O
ULA	O
would	O
read	O
a	O
different	O
set	O
of	O
40	O
bytes	O
for	O
every	O
display	O
scanline	O
in	O
order	O
to	O
produce	O
a	O
full	O
graphics	O
display	O
.	O
</s>
<s>
A	O
software	O
ROM	B-Device
worked	O
around	O
this	O
by	O
duplicating	O
the	O
data	O
intended	O
for	O
a	O
Mode	O
7	O
display	O
in	O
memory	O
.	O
</s>
<s>
Although	O
this	O
produced	O
a	O
Mode	O
7	O
that	O
had	O
less	O
of	O
an	O
impact	O
upon	O
CPU	B-General_Concept
performance	O
than	O
a	O
software	O
solution	O
,	O
gave	O
the	O
same	O
visual	O
quality	O
as	O
the	O
BBC	B-Device
Micro	I-Device
,	O
and	O
supported	O
direct	O
access	O
to	O
Mode	O
7	O
screen	O
addresses	O
as	O
well	O
as	O
accesses	O
via	O
operating	B-Operating_System
system	I-Operating_System
routines	O
,	O
it	O
still	O
used	O
10KB	O
of	O
memory	O
for	O
the	O
display	O
and	O
reduced	O
the	O
amount	O
of	O
readily-usable	O
application	O
memory	O
(	O
as	O
indicated	O
by	O
HIMEM	O
)	O
by	O
another	O
6KB	O
.	O
</s>
<s>
However	O
,	O
with	O
users	O
increasingly	O
able	O
to	O
rely	O
on	O
expansions	O
such	O
as	O
the	O
Slogger	O
Master	O
RAM	B-Architecture
board	O
to	O
provide	O
more	O
memory	O
,	O
and	O
with	O
this	O
combination	O
of	O
expansions	O
acknowledged	O
throughout	O
the	O
user	O
manual	O
,	O
the	O
emphasis	O
of	O
the	O
Mode	O
7	O
Simulator	O
and	O
Mark	O
2	O
Display	O
Unit	O
was	O
arguably	O
to	O
deliver	O
the	O
actual	O
display	O
capabilities	O
for	O
those	O
applications	O
that	O
needed	O
them	O
,	O
instead	O
of	O
using	O
Mode	O
7	O
as	O
a	O
way	O
of	O
economising	O
with	O
regard	O
to	O
memory	O
usage	O
,	O
and	O
to	O
do	O
so	O
at	O
a	O
reasonable	O
price	O
.	O
</s>
<s>
The	O
Jafa	O
interfaces	O
did	O
not	O
provide	O
a	O
Teletext	O
or	O
Viewdata	B-Application
reception	O
capability	O
,	O
but	O
the	O
Mark	O
2	O
was	O
explicitly	O
stated	O
to	O
work	O
in	O
conjunction	O
with	O
the	O
Morley	O
Electronics	O
Teletext	O
Adapter	O
.	O
</s>
<s>
Meanwhile	O
,	O
the	O
manual	O
for	O
the	O
Mark	O
2	O
noted	O
that	O
the	O
product	O
would	O
provide	O
the	O
functionality	O
of	O
a	O
Viewdata	B-Application
terminal	O
if	O
combined	O
with	O
Jafa	O
's	O
RS423	O
cartridge	B-Protocol
.	O
</s>
<s>
Morley	O
Electronics	O
produced	O
a	O
Teletext	O
Adaptor	O
expansion	O
for	O
the	O
BBC	B-Device
Micro	I-Device
and	O
the	O
Electron	O
.	O
</s>
<s>
Since	O
the	O
BBC	B-Device
Micro	I-Device
has	O
the	O
Mode	O
7	O
display	O
capability	O
,	O
the	O
model	O
aimed	O
at	O
the	O
BBC	B-Device
Micro	I-Device
merely	O
provided	O
the	O
content	O
reception	O
capability	O
needed	O
to	O
receive	O
and	O
decode	O
Teletext	O
signals	O
,	O
connecting	O
to	O
the	O
user	O
port	O
and	O
power	O
supply	O
.	O
</s>
<s>
However	O
,	O
the	O
Electron	O
models	O
provided	O
both	O
display	O
and	O
reception	O
capabilities	O
,	O
doing	O
so	O
by	O
routing	O
either	O
the	O
RGB	O
or	O
UHF	O
signals	O
(	O
depending	O
on	O
the	O
model	O
)	O
through	O
the	O
unit	O
in	O
order	O
to	O
introduce	O
the	O
Mode	O
7	O
output	O
produced	O
by	O
the	O
unit	O
,	O
also	O
connecting	O
via	O
a	O
cartridge	B-Protocol
.	O
</s>
<s>
The	O
Teletext	O
display	O
capabilities	O
in	O
the	O
Electron	O
models	O
exceeded	O
those	O
of	O
the	O
BBC	B-Device
Micro	I-Device
,	O
with	O
one	O
reviewer	O
noting	O
that	O
the	O
enhanced	O
capabilities	O
permitted	O
"	O
black	O
text	O
on	O
a	O
coloured	O
background	O
,	O
something	O
I	O
've	O
always	O
wanted	O
to	O
do	O
on	O
my	O
Beeb	O
"	O
.	O
</s>
<s>
Despite	O
Acorn	O
's	O
withdrawal	O
from	O
the	O
Electron	O
peripheral	O
market	O
,	O
Baildon	O
Electronics	O
developed	O
the	O
Advanced	O
Plus	O
5	O
(	O
AP5	O
)	O
expansion	O
,	O
featuring	O
Tube	O
,	O
1MHz	O
bus	O
and	O
user	O
port	O
interfaces	O
,	O
which	O
plugged	O
into	O
a	O
Plus	O
1	O
cartridge	B-Protocol
socket	O
.	O
</s>
<s>
This	O
provided	O
a	O
sufficient	O
level	O
of	O
compatibility	O
that	O
both	O
the	O
6502	B-General_Concept
and	O
Z80	O
second	O
processor	O
products	O
from	O
Acorn	O
were	O
shown	O
to	O
work	O
,	O
providing	O
a	O
Tube	O
implementation	O
that	O
was	O
"	O
as	O
faithful	O
as	O
you	O
can	O
get	O
"	O
,	O
with	O
it	O
also	O
being	O
noted	O
that	O
the	O
Electron	O
being	O
available	O
for	O
as	O
little	O
as	O
£50	O
at	O
that	O
point	O
in	O
its	O
commercial	O
lifespan	O
was	O
a	O
"	O
very	O
cheap	O
way	O
of	O
getting	O
a	O
CP/M	O
machine	O
"	O
.	O
</s>
<s>
Some	O
differences	O
in	O
the	O
memory	O
map	O
of	O
the	O
Electron	O
meant	O
that	O
BBC	B-Device
Micro	I-Device
software	O
would	O
need	O
modifications	O
to	O
work	O
on	O
the	O
Electron	O
with	O
AP5	O
.	O
</s>
<s>
The	O
additional	O
facilities	O
of	O
the	O
AP5	O
alongside	O
the	O
Tube	O
interface	O
permitted	O
various	O
expansions	O
for	O
the	O
BBC	B-Device
Micro	I-Device
to	O
be	O
made	O
available	O
for	O
the	O
Electron	O
.	O
</s>
<s>
In	O
1986	O
,	O
Permanent	O
Memory	O
Systems	O
announced	O
a	O
second	O
processor	O
product	O
for	O
the	O
Electron	O
,	O
the	O
PMS-E2P	O
,	O
as	O
a	O
self-contained	O
cartridge	B-Protocol
for	O
use	O
with	O
the	O
Plus	O
1	O
containing	O
a	O
second	O
2MHz	O
6502A	B-General_Concept
processor	O
plus	O
64KB	O
of	O
RAM	B-Architecture
,	O
priced	O
at	O
£89	O
.	O
</s>
<s>
The	O
supplied	O
software	O
supported	O
the	O
definition	O
of	O
spoken	O
words	O
built	O
up	O
from	O
the	O
allophones	O
these	O
allophones	O
or	O
sounds	O
being	O
stored	O
in	O
the	O
expansion	O
's	O
own	O
ROM	B-Device
and	O
for	O
catalogues	O
of	O
words	O
to	O
be	O
created	O
and	O
saved	O
.	O
</s>
<s>
The	O
expansion	O
used	O
the	O
General	B-Application
Instrument	I-Application
SP0256A-AL2	I-Application
speech	O
synthesis	O
chip	O
.	O
</s>
<s>
Originally	O
announced	O
in	O
1987	O
by	O
Project	O
Expansions	O
to	O
be	O
priced	O
at	O
around	O
£40	O
,	O
the	O
Sound	O
Expansion	O
cartridge	B-Protocol
could	O
be	O
fitted	O
in	O
a	O
Plus	O
1	O
(	O
or	O
compatible	O
)	O
slot	O
and	O
provide	O
sound	O
output	O
equivalent	O
to	O
that	O
of	O
the	O
BBC	B-Device
Micro	I-Device
,	O
with	O
Superior	B-Device
Software	I-Device
's	O
Speech	O
bundled	O
as	O
a	O
"	O
limited	O
offer	O
"	O
.	O
</s>
<s>
A	O
product	O
of	O
the	O
same	O
name	O
and	O
with	O
similar	O
functionality	O
was	O
subsequently	O
sold	O
by	O
Complex	O
Software	O
for	O
around	O
£55	O
,	O
employing	O
its	O
own	O
adjustable	O
speaker	O
in	O
the	O
cartridge	B-Protocol
unit	O
.	O
</s>
<s>
Superior	B-Device
Software	I-Device
had	O
announced	O
a	O
version	O
of	O
Speech	O
for	O
the	O
unexpanded	O
Acorn	B-Device
Electron	I-Device
in	O
1986	O
,	O
but	O
this	O
was	O
never	O
released	O
.	O
</s>
<s>
The	O
only	O
functional	O
differences	O
between	O
the	O
Electron	O
adaptation	O
and	O
the	O
original	O
BBC	B-Device
Micro	I-Device
unit	O
involved	O
the	O
use	O
of	O
Mode	O
6	O
for	O
the	O
display	O
and	O
the	O
reduced	O
performance	O
of	O
the	O
Electron	O
imposing	O
some	O
limitations	O
on	O
processing	O
in	O
programs	O
written	O
for	O
the	O
system	O
,	O
although	O
this	O
was	O
not	O
thought	O
to	O
prevent	O
most	O
programs	O
for	O
the	O
system	O
from	O
working	O
on	O
the	O
Electron	O
version	O
.	O
</s>
<s>
This	O
consisted	O
of	O
a	O
rebadged	O
Electron	O
plus	O
a	O
large	O
expansion	O
unit	O
containing	O
32KB	O
of	O
battery-backed	O
RAM	B-Architecture
(	O
making	O
up	O
64KB	O
of	O
RAM	B-Architecture
in	O
total	O
)	O
,	O
up	O
to	O
64KB	O
of	O
ROM	B-Device
resident	O
in	O
four	O
sockets	O
(	O
making	O
up	O
to	O
96KB	O
of	O
ROM	B-Device
in	O
total	O
)	O
,	O
a	O
Centronics	B-Device
printer	I-Device
port	I-Device
,	O
an	O
RS423	O
serial	O
port	O
,	O
a	O
modem	B-Application
,	O
and	O
the	O
speech	O
generator	O
previously	O
offered	O
for	O
the	O
BBC	B-Device
Micro	I-Device
.	O
</s>
<s>
The	O
ROM	B-Device
firmware	O
provided	O
dial-up	O
communications	O
facilities	O
,	O
text	O
editing	O
and	O
text	O
messaging	O
functions	O
.	O
</s>
<s>
The	O
Electron	O
was	O
said	O
to	O
be	O
particularly	O
suitable	O
for	O
deployment	O
in	O
this	O
application	O
in	O
that	O
it	O
had	O
a	O
"	O
large	O
expansion	O
bus	O
"	O
,	O
ostensibly	O
making	O
the	O
machine	O
amenable	O
to	O
the	O
necessary	O
adaptations	O
required	O
for	O
the	O
role	O
,	O
together	O
with	O
its	O
"	O
price	O
,	O
and	O
the	O
fact	O
it	O
has	O
a	O
real	O
keyboard	B-Device
"	O
.	O
</s>
<s>
Nevertheless	O
,	O
the	O
M2105	O
offered	O
interoperability	O
with	O
other	O
BT	O
products	O
such	O
as	O
the	O
QWERTYphone	O
which	O
was	O
able	O
to	O
receive	O
messages	O
from	O
the	O
M2105	O
and	O
the	O
Merlin	B-Device
Tonto	I-Device
.	O
</s>
<s>
The	O
hardware	O
specifications	O
of	O
the	O
M2105	O
,	O
observed	O
from	O
manufactured	O
units	O
,	O
include	O
the	O
6502	B-General_Concept
CPU	B-General_Concept
(	O
SY6502	O
or	O
R6502	O
)	O
,	O
ULA	O
and	O
32KB	O
of	O
dynamic	O
RAM	B-Architecture
fitted	O
in	O
the	O
Electron	O
main	O
unit	O
,	O
plus	O
32KB	O
of	O
static	O
RAM	B-Architecture
,	O
two	O
6522	B-Device
VIA	O
devices	O
for	O
interfacing	O
,	O
AM2910PC	O
modem	B-Application
,	O
SCN2681A	O
UART	O
,	O
and	O
TMS5220	B-Application
plus	O
TMS6100	O
for	O
speech	O
synthesis	O
.	O
</s>
<s>
The	O
components	O
chosen	O
and	O
the	O
capabilities	O
provided	O
(	O
excluding	O
speech	O
synthesis	O
)	O
are	O
broadly	O
similar	O
to	O
those	O
featured	O
by	O
the	O
Acorn	B-Device
Communicator	I-Device
which	O
was	O
another	O
product	O
of	O
Acorn	O
's	O
custom	O
systems	O
division	O
.	O
</s>
<s>
The	O
product	O
documentation	O
indicates	O
a	O
specification	O
with	O
48KB	O
of	O
RAM	B-Architecture
plus	O
16KB	O
of	O
"	O
non	O
volatile	O
CMOS	O
RAM	B-Architecture
"	O
and	O
96KB	O
of	O
ROM	B-Device
,	O
although	O
this	O
particular	O
composition	O
of	O
RAM	B-Architecture
is	O
apparently	O
contradicted	O
by	O
the	O
RAM	B-Architecture
devices	O
present	O
on	O
surviving	O
M2105	O
machines	O
.	O
</s>
<s>
However	O
,	O
the	O
earlier	O
Chain	O
variant	O
of	O
the	O
board	O
does	O
appear	O
to	O
provide	O
only	O
16KB	O
of	O
static	O
RAM	B-Architecture
using	O
two	O
HM6264LP-15	O
chips	O
,	O
also	O
providing	O
an	O
extra	O
16KB	O
of	O
dynamic	O
RAM	B-Architecture
using	O
eight	O
MK4516-15	O
chips	O
,	O
suggesting	O
that	O
the	O
product	O
evolved	O
during	O
development	O
.	O
</s>
<s>
Much	O
of	O
the	O
core	O
functionality	O
of	O
the	O
BBC	B-Device
Micro	I-Device
the	O
video	O
and	O
memory	O
controller	O
,	O
cassette	O
input/output	O
,	O
timers	O
and	O
sound	O
generation	O
was	O
replicated	O
using	O
a	O
single	O
customised	O
ULA	O
chip	O
designed	O
by	O
Acorn	O
in	O
conjunction	O
with	O
Ferranti	O
,	O
albeit	O
with	O
only	O
one	O
sound	O
channel	O
instead	O
of	O
three	O
(	O
and	O
one	O
noise	O
channel	O
)	O
,	O
and	O
without	O
the	O
character-based	O
Teletext	O
Mode	O
7	O
.	O
</s>
<s>
The	O
edge	O
connector	O
on	O
the	O
rear	O
of	O
the	O
Electron	O
exposes	O
all	O
address	O
and	O
data	O
bus	O
lines	O
from	O
the	O
CPU	B-General_Concept
,	O
including	O
the	O
upper	O
eight	O
bits	O
of	O
the	O
address	O
bus	O
,	O
in	O
contrast	O
to	O
the	O
limited	O
selection	O
available	O
via	O
the	O
BBC	B-Device
Micro	I-Device
's	O
expansion	O
ports	O
,	O
with	O
the	O
One	O
Megahertz	O
Bus	O
as	O
the	O
principal	O
mechanism	O
for	O
general	O
purpose	O
expansion	O
on	O
the	O
BBC	B-Device
Micro	I-Device
only	O
providing	O
the	O
lower	O
eight	O
bits	O
of	O
the	O
address	O
bus	O
.	O
</s>
<s>
In	O
addition	O
,	O
various	O
control	O
signals	O
provided	O
by	O
the	O
CPU	B-General_Concept
and	O
ULA	O
are	O
exposed	O
via	O
the	O
Electron	O
's	O
expansion	O
connector	O
.	O
</s>
<s>
The	O
keyboard	B-Device
includes	O
a	O
form	O
of	O
quick	O
keyword	O
input	O
,	O
similar	O
to	O
that	O
used	O
on	O
the	O
Sinclair	B-Operating_System
ZX	I-Operating_System
Spectrum	I-Operating_System
,	O
through	O
use	O
of	O
the	O
key	O
in	O
combination	O
with	O
other	O
keys	O
labelled	O
with	O
BASIC	O
keywords	O
.	O
</s>
<s>
The	O
ULA	O
mediates	O
access	O
to	O
32KB	O
of	O
addressable	O
RAM	B-Architecture
using	O
4	O
64-kilobit	O
RAM	B-Architecture
chips	I-Architecture
(	O
4164	O
)	O
,	O
sharing	O
the	O
RAM	B-Architecture
between	O
the	O
CPU	B-General_Concept
and	O
the	O
video	O
signal	O
generation	O
(	O
or	O
screen	O
refresh	O
)	O
performed	O
by	O
the	O
ULA	O
itself	O
.	O
</s>
<s>
Two	O
accesses	O
have	O
to	O
be	O
made	O
to	O
the	O
RAM	B-Architecture
to	O
get	O
each	O
byte	O
(	O
albeit	O
with	O
a	O
single	O
RAS	O
)	O
,	O
delivering	O
a	O
maximum	O
transfer	O
rate	O
to	O
or	O
from	O
RAM	B-Architecture
of	O
one	O
byte	O
per	O
2MHz	O
cycle	O
.	O
</s>
<s>
Due	O
to	O
signalling	O
constraints	O
,	O
the	O
CPU	B-General_Concept
can	O
only	O
access	O
RAM	B-Architecture
at	O
1MHz	O
,	O
even	O
when	O
it	O
is	O
not	O
competing	O
with	O
the	O
video	O
system	O
.	O
</s>
<s>
When	O
the	O
ULA	O
is	O
consuming	O
all	O
of	O
the	O
RAM	B-Architecture
bandwidth	O
during	O
the	O
active	O
portion	O
of	O
a	O
display	O
line	O
,	O
the	O
CPU	B-General_Concept
is	O
unable	O
to	O
access	O
the	O
RAM	B-Architecture
.	O
</s>
<s>
(	O
The	O
Electron	O
uses	O
the	O
Synertek	O
variant	O
of	O
the	O
6502	B-General_Concept
processor	I-General_Concept
as	O
that	O
allowed	O
the	O
clock	O
to	O
be	O
stopped	O
for	O
this	O
40	O
microsecond	O
period	O
.	O
)	O
</s>
<s>
In	O
other	O
modes	O
the	O
CPU	B-General_Concept
and	O
video	O
accesses	O
are	O
interleaved	O
with	O
each	O
accessor	O
acquiring	O
bytes	O
at	O
1MHz	O
.	O
</s>
<s>
In	O
contrast	O
,	O
the	O
BBC	B-Device
Micro	I-Device
employs	O
one	O
or	O
two	O
sets	O
of	O
eight	O
16-kilobit	O
devices	O
,	O
with	O
the	O
RAM	B-Architecture
running	O
at	O
twice	O
the	O
speed	O
(	O
4MHz	O
)	O
of	O
the	O
CPU	B-General_Concept
(	O
2MHz	O
)	O
,	O
allowing	O
the	O
video	O
system	O
(	O
screen	O
refresh	O
)	O
and	O
CPU	B-General_Concept
memory	O
accesses	O
to	O
be	O
interleaved	O
,	O
with	O
each	O
accessor	O
able	O
to	O
transfer	O
bytes	O
at	O
2MHz	O
.	O
</s>
<s>
The	O
RAM	B-Architecture
access	O
limitations	O
imposed	O
by	O
the	O
Electron	O
's	O
ULA	O
therefore	O
reduce	O
the	O
effective	O
CPU	B-General_Concept
speed	O
by	O
as	O
much	O
as	O
a	O
factor	O
of	O
four	O
relative	O
to	O
the	O
BBC	B-Device
Micro	I-Device
in	O
the	O
more	O
demanding	O
display	O
modes	O
,	O
and	O
as	O
much	O
as	O
a	O
factor	O
of	O
two	O
otherwise	O
.	O
</s>
<s>
Byte	O
transfers	O
from	O
ROM	B-Device
occur	O
at	O
2MHz	O
,	O
however	O
.	O
</s>
<s>
CPU	B-General_Concept
runs	O
at	O
2	O
MHz	O
when	O
accessing	O
ROM	B-Device
and	O
1MHz	O
when	O
accessing	O
RAM	B-Architecture
.	O
</s>
<s>
The	O
CPU	B-General_Concept
is	O
also	O
periodically	O
halted	O
.	O
</s>
<s>
Acorn	O
ostensibly	O
intended	O
the	O
composite	O
output	O
to	O
be	O
a	O
high-quality	O
output	O
for	O
monochrome	B-Device
monitors	I-Device
,	O
with	O
the	O
RGB	O
output	O
being	O
the	O
preferred	O
high-quality	O
output	O
for	O
colour	O
images	O
.	O
</s>
<s>
Like	O
the	O
BBC	B-Device
Micro	I-Device
,	O
the	O
Electron	O
was	O
constrained	O
by	O
limited	O
memory	O
resources	O
.	O
</s>
<s>
Of	O
the	O
32KB	O
RAM	B-Architecture
,	O
3½	O
KB	O
was	O
allocated	O
to	O
the	O
OS	O
at	O
startup	O
and	O
at	O
least	O
10KB	O
was	O
taken	O
up	O
by	O
the	O
display	O
buffer	O
in	O
contiguous	O
display	O
modes	O
.	O
</s>
<s>
Although	O
programs	O
running	O
on	O
the	O
BBC	B-Device
Micro	I-Device
could	O
use	O
the	O
machine	O
's	O
6522	B-Device
chip	O
to	O
trigger	O
interrupts	O
at	O
certain	O
points	O
in	O
the	O
update	O
of	O
each	O
display	O
frame	O
,	O
using	O
these	O
events	O
to	O
change	O
the	O
palette	O
and	O
potentially	O
switching	O
all	O
colours	O
to	O
black	O
,	O
thus	O
blanking	O
regions	O
of	O
the	O
screen	O
and	O
hiding	O
non-graphical	O
data	O
that	O
had	O
been	O
stored	O
in	O
screen	O
memory	O
,	O
the	O
Electron	O
lacked	O
such	O
hardware	O
capabilities	O
as	O
standard	O
.	O
</s>
<s>
One	O
notable	O
example	O
is	O
Superior	B-Device
Software	I-Device
's	O
Citadel	B-Application
.	O
</s>
<s>
Although	O
page	O
flipping	O
was	O
a	O
hardware	O
possibility	O
,	O
the	O
limited	O
memory	O
forced	O
most	O
applications	O
to	O
do	O
all	O
their	O
drawing	O
directly	O
to	O
the	O
visible	O
screen	O
,	O
often	O
resulting	O
in	O
graphical	O
flicker	B-General_Concept
or	O
visible	O
redraw	O
.	O
</s>
<s>
A	O
notable	O
exception	O
is	O
Players	O
 '	O
Joe	B-Application
Blade	I-Application
series	O
.	O
</s>
<s>
Firetrack	B-Application
,	O
released	O
on	O
a	O
compilation	O
by	O
Superior	B-Device
Software	I-Device
,	O
exploits	O
a	O
division	O
in	O
the	O
way	O
the	O
Electron	O
handles	O
its	O
display	O
of	O
the	O
seven	O
available	O
graphics	O
modes	O
,	O
two	O
are	O
configured	O
so	O
that	O
the	O
final	O
two	O
of	O
every	O
ten	O
scanlines	O
are	O
blank	O
and	O
are	O
not	O
based	O
on	O
the	O
contents	O
of	O
RAM	B-Architecture
.	O
</s>
<s>
Firetrack	B-Application
switches	O
from	O
a	O
non-continuous	O
to	O
a	O
continuous	O
graphics	O
mode	O
part	O
way	O
down	O
the	O
display	O
.	O
</s>
<s>
Exile	B-Application
turns	O
the	O
Electron	O
's	O
one	O
channel	O
output	O
into	O
a	O
digital	O
speaker	O
for	O
PCM	B-Algorithm
output	O
.	O
</s>
<s>
This	O
gives	O
the	O
effect	O
of	O
a	O
simple	O
toggle	O
speaker	O
similar	O
to	O
that	O
seen	O
in	O
the	O
48KB	O
Sinclair	B-Operating_System
ZX	I-Operating_System
Spectrum	I-Operating_System
.	O
</s>
<s>
Exile	B-Application
uses	O
this	O
to	O
output	O
1-bit	O
audio	O
samples	O
.	O
</s>
<s>
As	O
part	O
of	O
their	O
copy	O
protection	O
,	O
illegal	O
copies	O
of	O
Aardvark	O
Software	O
's	O
Frak	B-Application
!	I-Application
</s>
<s>
and	O
Zalaga	B-Application
would	O
cause	O
a	O
pseudo-polyphonic	O
rendition	O
of	O
Trumpet	O
Hornpipe	O
,	O
the	O
Captain	O
Pugwash	O
theme	O
tune	O
,	O
to	O
play	O
endlessly	O
rather	O
than	O
loading	O
the	O
game	O
properly	O
(	O
Pugwash	O
being	O
a	O
pirate	O
)	O
.	O
</s>
<s>
A	O
range	O
of	O
titles	O
were	O
made	O
available	O
on	O
cassette	O
at	O
the	O
launch	O
of	O
the	O
Electron	O
through	O
the	O
Acornsoft	O
publishing	O
arm	O
of	O
Acorn	O
,	O
including	O
a	O
number	O
of	O
games	O
,	O
the	O
Forth	B-Application
and	O
Lisp	B-Language
languages	I-Language
,	O
and	O
a	O
handful	O
of	O
other	O
educational	O
and	O
productivity	O
titles	O
.	O
</s>
<s>
Acorn	O
's	O
decision	O
to	O
provide	O
the	O
Electron	O
with	O
a	O
degree	O
of	O
compatibility	O
with	O
the	O
BBC	B-Device
Micro	I-Device
meant	O
that	O
a	O
number	O
of	O
titles	O
already	O
available	O
for	O
the	O
older	O
machine	O
could	O
be	O
expected	O
to	O
run	O
on	O
its	O
new	O
machine	O
,	O
with	O
only	O
minor	O
cosmetic	O
issues	O
occurring	O
when	O
running	O
some	O
titles	O
.	O
</s>
<s>
Of	O
the	O
Acornsoft	O
languages	O
,	O
the	O
existing	O
Forth	B-Application
and	O
Lisp	B-Language
language	I-Language
releases	O
worked	O
on	O
the	O
Electron	O
(	O
these	O
being	O
re-released	O
specially	O
for	O
the	O
machine	O
)	O
,	O
together	O
with	O
BCPL	O
and	O
Microtext	O
(	O
which	O
remained	O
BBC-only	O
releases	O
)	O
.	O
</s>
<s>
Various	O
applications	O
in	O
Acornsoft	O
's	O
View	O
suite	O
,	O
together	O
with	O
the	O
languages	O
Comal	O
,	O
Logo	B-Device
and	O
ISO	O
Pascal	O
,	O
were	O
reported	O
as	O
being	O
compatible	O
with	O
the	O
Electron	O
,	O
as	O
were	O
some	O
titles	O
from	O
BBC	O
Soft	O
and	O
other	O
developers	O
.	O
</s>
<s>
A	O
significant	O
selling	O
point	O
for	O
the	O
Electron	O
was	O
its	O
built-in	O
BBC	B-Language
BASIC	I-Language
interpreter	O
,	O
providing	O
a	O
degree	O
of	O
familiarity	O
from	O
the	O
BBC	B-Device
Micro	I-Device
along	O
with	O
a	O
level	O
of	O
compatibility	O
with	O
the	O
earlier	O
machine	O
.	O
</s>
<s>
However	O
,	O
as	O
had	O
been	O
the	O
case	O
with	O
the	O
BBC	B-Device
Micro	I-Device
,	O
support	O
for	O
other	O
languages	O
was	O
quickly	O
forthcoming	O
,	O
facilitated	O
by	O
the	O
common	O
heritage	O
of	O
the	O
two	O
systems	O
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
early	O
releases	O
,	O
Forth	B-Application
and	O
Lisp	B-Language
,	O
Acornsoft	O
released	O
the	O
Pascal	O
subset	O
,	O
S-Pascal	O
,	O
on	O
cassette	O
and	O
followed	O
up	O
with	O
an	O
ISO	O
Pascal	O
implementation	O
on	O
ROM	B-Protocol
cartridge	I-Protocol
,	O
the	O
latter	O
providing	O
two	O
16KB	O
ROMs	O
containing	O
a	O
program	O
editor	O
and	O
a	O
Pascal	O
compiler	O
producing	O
intermediate	O
code	O
that	O
required	O
Pascal	O
run-time	O
routines	O
to	O
be	O
loaded	O
.	O
</s>
<s>
ISO	O
Pascal	O
had	O
Oxford	O
Pascal	O
as	O
a	O
direct	O
competitor	O
offering	O
a	O
range	O
of	O
features	O
differentiating	O
it	O
from	O
Acornsoft	O
's	O
product	O
,	O
notably	O
a	O
compiler	O
that	O
could	O
produce	O
a	O
stand-alone	O
"	O
relocatable	O
6502	B-General_Concept
machine-code	O
file	O
"	O
.	O
</s>
<s>
Acornsoft	O
later	O
released	O
the	O
ISO	O
Pascal	O
Stand	O
Alone	O
Generator	O
product	O
for	O
the	O
BBC	B-Device
Micro	I-Device
and	O
Master	B-Device
series	I-Device
,	O
permitting	O
the	O
generation	O
of	O
executable	O
programs	O
embedding	O
"	O
sections	O
of	O
the	O
interpreter	O
"	O
required	O
by	O
each	O
program	O
,	O
with	O
such	O
executables	O
being	O
subject	O
to	O
various	O
licensing	O
restrictions	O
.	O
</s>
<s>
Acornsoft	O
Forth	B-Application
,	O
aiming	O
for	O
compliance	O
with	O
the	O
Forth-79	O
standard	O
,	O
was	O
regarded	O
as	O
"	O
an	O
excellent	O
implementation	O
of	O
the	O
language	O
"	O
.	O
</s>
<s>
It	O
saw	O
competition	O
from	O
Skywave	O
Software	O
's	O
Multi-Forth	O
83	O
which	O
was	O
delivered	O
on	O
a	O
ROM	B-Device
chip	I-Device
,	O
supported	O
the	O
Forth-83	O
standard	O
,	O
and	O
provided	O
a	O
multitasking	O
environment	O
.	O
</s>
<s>
Future	O
availability	O
of	O
Multi-Forth	O
83	O
on	O
ROM	B-Protocol
cartridge	I-Protocol
was	O
advertised	O
.	O
</s>
<s>
With	O
the	O
launch	O
of	O
the	O
Plus	O
1	O
,	O
Acornsoft	B-Language
Lisp	I-Language
was	O
also	O
made	O
available	O
on	O
cartridge	B-Protocol
.	O
</s>
<s>
This	O
Lisp	B-Language
implementation	O
provided	O
only	O
the	O
"	O
bare	O
essentials	O
"	O
of	O
a	O
Lisp	B-Language
system	O
that	O
"	O
a	O
small	O
micro	O
such	O
as	O
the	O
Electron	O
"	O
could	O
hope	O
to	O
be	O
able	O
to	O
support	O
.	O
</s>
<s>
However	O
,	O
with	O
the	O
interpreter	O
and	O
initialised	O
workspace	O
being	O
loaded	O
from	O
cassette	O
into	O
RAM	B-Architecture
in	O
the	O
earlier	O
release	O
,	O
one	O
stated	O
advantage	O
of	O
the	O
ROM	B-Device
version	O
was	O
the	O
availability	O
of	O
more	O
memory	O
for	O
use	O
by	O
programs	O
,	O
with	O
the	O
immediacy	O
of	O
a	O
Lisp	B-Language
system	O
provided	O
as	O
a	O
language	O
ROM	B-Device
being	O
an	O
implicit	O
benefit	O
.	O
</s>
<s>
Acornsoft	O
provided	O
two	O
products	O
offering	O
different	O
degrees	O
of	O
support	O
for	O
the	O
Logo	B-Device
programming	I-Device
language	I-Device
.	O
</s>
<s>
Turtle	O
Graphics	O
was	O
a	O
cassette-based	O
product	O
,	O
available	O
alongside	O
Forth	B-Application
,	O
Lisp	B-Language
and	O
S-Pascal	O
amongst	O
the	O
first	O
titles	O
released	O
for	O
the	O
Electron	O
,	O
featuring	O
a	O
subset	O
of	O
Logo	B-Device
focused	O
on	O
the	O
interactive	O
aspects	O
of	O
the	O
language	O
.	O
</s>
<s>
Acornsoft	O
Logo	B-Device
was	O
provided	O
on	O
ROM	B-Protocol
cartridge	I-Protocol
and	O
offered	O
a	O
vocabulary	O
of	O
over	O
200	O
commands	O
as	O
part	O
of	O
a	O
more	O
comprehensive	O
implementation	O
of	O
the	O
language	O
,	O
exposing	O
its	O
list	B-Language
processing	I-Language
foundations	O
.	O
</s>
<s>
Turtle	O
Graphics	O
was	O
substantially	O
cheaper	O
than	O
Logo	B-Device
:	O
by	O
1987	O
,	O
the	O
former	O
had	O
been	O
reportedly	O
discounted	O
to	O
under	O
£3	O
whereas	O
the	O
latter	O
cost	O
"	O
less	O
than	O
£30	O
"	O
.	O
</s>
<s>
Unlike	O
other	O
Acornsoft	O
language	O
products	O
,	O
however	O
,	O
Logo	B-Device
was	O
supplied	O
with	O
"	O
two	O
thick	O
manuals	O
"	O
.	O
</s>
<s>
Of	O
the	O
twelve	O
software	O
titles	O
announced	O
by	O
Acornsoft	O
for	O
the	O
Electron	O
at	O
the	O
machine	O
's	O
launch	O
,	O
six	O
were	O
games	O
titles	O
:	O
Snapper	O
,	O
Monsters	O
(	O
a	O
clone	O
of	O
Space	B-Application
Panic	I-Application
)	O
,	O
Meteors	O
(	O
a	O
clone	O
of	O
Asteroids	B-Application
)	O
,	O
Starship	O
Command	O
,	O
Chess	O
,	O
and	O
the	O
combined	O
title	O
Draughts	O
and	O
Reversi	O
.	O
</s>
<s>
When	O
the	O
Plus	O
1	O
expansion	O
was	O
launched	O
in	O
1984	O
,	O
three	O
of	O
these	O
titles	O
-	O
Hopper	O
,	O
Snapper	O
and	O
Starship	O
Command	O
-	O
were	O
among	O
the	O
six	O
ROM	B-Protocol
cartridge	I-Protocol
titles	O
available	O
at	O
launch	O
,	O
together	O
with	O
the	O
adventure	O
Countdown	O
to	O
Doom	O
.	O
</s>
<s>
Acornsoft	O
would	O
continue	O
to	O
release	O
games	O
including	O
those	O
based	O
on	O
existing	O
arcade	O
games	O
such	O
as	O
Arcadians	O
(	O
based	O
on	O
Galaxian	B-Application
)	O
and	O
Hopper	O
(	O
based	O
on	O
Frogger	B-Application
)	O
,	O
as	O
well	O
as	O
original	O
titles	O
such	O
as	O
Free	O
Fall	O
and	O
Elite	B-Application
.	O
</s>
<s>
Micro	O
Power	O
,	O
already	O
an	O
established	O
BBC	B-Device
Micro	I-Device
games	O
publisher	O
,	O
also	O
entered	O
the	O
Electron	O
market	O
at	O
a	O
relatively	O
early	O
stage	O
,	O
offering	O
ten	O
initial	O
titles	O
either	O
converted	O
from	O
the	O
BBC	B-Device
Micro	I-Device
,	O
in	O
the	O
case	O
of	O
Escape	O
from	O
Moonbase	O
Alpha	O
and	O
Killer	O
Gorilla	O
,	O
or	O
"	O
completely	O
re-written	O
"	O
,	O
in	O
the	O
case	O
of	O
Moonraider	O
(	O
due	O
to	O
differences	O
in	O
the	O
screen	O
handling	O
between	O
the	O
machines	O
)	O
.	O
</s>
<s>
Superior	B-Device
Software	I-Device
,	O
also	O
a	O
significant	O
publisher	O
for	O
the	O
BBC	B-Device
Micro	I-Device
,	O
routinely	O
released	O
games	O
for	O
both	O
machines	O
,	O
notably	O
a	O
licensed	O
version	O
of	O
Atari	O
's	O
Tempest	B-Application
in	O
1985	O
,	O
but	O
also	O
successful	O
original	O
titles	O
such	O
as	O
the	B-Application
Repton	I-Application
series	I-Application
of	O
games	O
,	O
Citadel	B-Application
,	O
Thrust	B-Application
and	O
Galaforce	O
.	O
</s>
<s>
Superior	O
's	O
role	O
in	O
games	O
publishing	O
for	O
the	O
Acorn	O
machines	O
expanded	O
in	O
1986	O
when	O
the	O
company	O
acquired	O
the	O
right	O
to	O
use	O
the	O
Acornsoft	O
brand	O
,	O
leading	O
to	O
the	O
co-branding	O
of	O
games	O
and	O
compilations	O
released	O
by	O
the	O
company	O
and	O
the	O
re-release	O
of	O
existing	O
Acornsoft	O
titles	O
with	O
this	O
branding	O
,	O
Elite	B-Application
among	O
them	O
.	O
</s>
<s>
The	O
company	O
would	O
subsequently	O
release	O
another	O
"	O
masterpiece	O
"	O
with	O
bundled	O
novella	O
-	O
the	O
1988	O
game	O
Exile	B-Application
-	O
as	O
well	O
as	O
numerous	O
conversions	O
and	O
compilations	O
.	O
</s>
<s>
By	O
1988	O
,	O
the	O
"	O
big	O
three	O
"	O
full-price	O
games	O
publishers	O
for	O
the	O
Acorn	O
8-bit	O
market	O
were	O
identified	O
as	O
Superior	B-Device
Software	I-Device
,	O
Audiogenic	O
(	O
ASL	O
)	O
and	O
Tynesoft	O
,	O
with	O
Top	O
Ten	O
and	O
Alternative	O
Software	O
being	O
the	O
significant	O
budget	O
publishers	O
,	O
and	O
other	O
"	O
strong	O
contenders	O
"	O
being	O
Godax	O
,	O
Mandarin	O
and	O
Bug	O
Byte	O
,	O
this	O
assessment	O
made	O
from	O
the	O
perspective	O
of	O
an	O
established	O
games	O
author	O
evaluating	O
trustworthy	O
publishers	O
for	O
aspiring	O
authors	O
.	O
</s>
<s>
Commercial	O
considerations	O
motivated	O
authors	O
to	O
make	O
their	O
games	O
available	O
for	O
the	O
Electron	O
due	O
to	O
its	O
importance	O
in	O
sales	O
terms	O
,	O
representing	O
"	O
around	O
half	O
of	O
the	O
Acorn	O
market	O
"	O
,	O
with	O
it	O
being	O
regarded	O
as	O
"	O
almost	O
compulsory	O
for	O
any	O
mainstream	O
game	O
"	O
to	O
have	O
an	O
Electron	O
version	O
"	O
unless	O
your	O
game	O
is	O
a	O
state-of-the-art	O
masterpiece	O
"	O
,	O
with	O
Revs	O
,	O
Cholo	O
and	O
Sentinel	O
cited	O
as	O
such	O
BBC	B-Device
Micro	I-Device
exclusives	O
.	O
</s>
<s>
Although	O
the	O
Electron	O
imposed	O
additional	O
technical	O
constraints	O
on	O
authors	O
accustomed	O
to	O
the	O
BBC	B-Device
Micro	I-Device
,	O
some	O
authors	O
were	O
able	O
to	O
use	O
this	O
to	O
their	O
creative	O
advantage	O
.	O
</s>
<s>
For	O
instance	O
,	O
of	O
Frak	B-Application
!	I-Application
</s>
<s>
Although	O
not	O
as	O
well	O
supported	O
by	O
the	O
biggest	O
software	O
publishers	O
as	O
rivals	O
like	O
the	O
Commodore	O
64	O
and	O
Sinclair	B-Operating_System
ZX	I-Operating_System
Spectrum	I-Operating_System
,	O
a	O
good	O
range	O
of	O
games	O
were	O
available	O
for	O
the	O
Electron	O
including	O
popular	O
multi-format	O
games	O
such	O
as	O
Chuckie	B-Application
Egg	I-Application
.	O
</s>
<s>
There	O
were	O
also	O
many	O
popular	O
games	O
officially	O
converted	O
to	O
the	O
Electron	O
from	O
arcade	O
machines	O
(	O
including	O
Crystal	B-Application
Castles	I-Application
,	O
Tempest	B-Application
,	O
Commando	B-Application
,	O
Paperboy	B-Device
and	O
Yie	B-Application
Ar	I-Application
Kung-Fu	I-Application
)	O
and	O
other	O
home	O
computer	O
systems	O
(	O
including	O
Impossible	B-Application
Mission	I-Application
,	O
Jet	B-Application
Set	I-Application
Willy	I-Application
,	O
The	B-Application
Way	I-Application
of	I-Application
the	I-Application
Exploding	I-Application
Fist	I-Application
,	O
Tetris	B-Device
,	O
The	B-Application
Last	I-Application
Ninja	I-Application
,	O
Barbarian	B-Application
,	O
Ballistix	B-Application
,	O
Predator	B-Application
,	O
Hostages	B-Device
and	O
SimCity	B-Application
)	O
.	O
</s>
<s>
There	O
were	O
around	O
1,400	O
games	O
released	O
for	O
the	O
Acorn	B-Device
Electron	I-Device
,	O
several	O
thousand	O
extra	O
public	O
domain	O
titles	O
were	O
released	O
on	O
disc	O
through	O
Public	O
Domain	O
libraries	O
.	O
</s>
<s>
Notable	O
enterprises	O
which	O
produced	O
discs	O
of	O
such	O
software	O
are	O
BBC	O
PD	O
,	O
EUG	O
(	O
Electron	O
User	O
Group	O
)	O
and	O
HeadFirst	B-Device
PD	I-Device
.	O
</s>
<s>
Several	O
emulators	O
of	O
the	O
machine	O
exist	O
:	O
ElectrEm	O
for	O
Windows/Linux/macOS	O
,	O
Elkulator	O
for	O
Windows/Linux/DOS	O
,	O
ElkJS	O
is	O
a	O
browser-based	O
(	O
JavaScript/HTML5	O
)	O
emulator	O
,	O
and	O
the	O
multi-system	O
emulators	O
MESS	O
and	O
Clock	O
Signal	O
feature	O
support	O
for	O
the	O
Electron	O
.	O
</s>
<s>
There	O
are	O
also	O
two	O
known	O
FPGA	B-Architecture
based	O
recreations	O
of	O
the	O
Acorn	B-Device
Electron	I-Device
hardware	O
.	O
</s>
<s>
ElectronFPGA	O
for	O
the	O
Papilio	O
Duo	O
hardware	O
and	O
the	O
Acorn-Electron	O
core	O
for	O
the	O
FPGA	B-Architecture
Arcade	O
"	O
Replay	O
"	O
board	O
.	O
</s>
<s>
The	O
operating	B-Operating_System
system	I-Operating_System
ROM	B-Device
locations	O
0xFC00-0xFFFF	O
contain	O
the	O
details	O
of	O
some	O
members	O
of	O
the	O
Electron	O
's	O
design	O
team	O
,	O
these	O
differing	O
somewhat	O
from	O
those	O
listed	O
in	O
the	O
corresponding	O
message	O
in	O
the	O
BBC	B-Device
Model	I-Device
B	I-Device
ROM	B-Device
:	O
</s>
<s>
Additionally	O
,	O
the	O
last	O
bytes	O
of	O
both	O
the	O
BASIC	O
ROM	B-Device
and	O
the	O
Plus	O
3	O
interface	O
's	O
ADFS	O
v1.0	O
ROM	B-Device
include	O
the	O
word	O
"	O
Roger	O
"	O
,	O
thought	O
to	O
be	O
a	O
reference	O
to	O
Roger	O
Wilson	O
.	O
</s>
