<s>
The	O
Bally	B-Device
Astrocade	I-Device
(	O
also	O
known	O
as	O
Bally	B-Device
Arcade	I-Device
or	O
initially	O
as	O
Bally	B-Device
ABA-1000	I-Device
)	O
is	O
a	O
second-generation	B-Application
home	B-Device
video	I-Device
game	I-Device
console	I-Device
and	O
simple	O
computer	O
system	O
designed	O
by	O
a	O
team	O
at	O
Midway	O
,	O
at	O
that	O
time	O
the	O
videogame	O
division	O
of	O
Bally	O
.	O
</s>
<s>
It	O
was	O
originally	O
announced	O
as	O
the	O
"	O
Bally	O
Home	B-Device
Library	I-Device
Computer	I-Device
"	O
in	O
October	O
1977	B-Application
and	O
initially	O
made	O
available	O
for	O
mail	O
order	O
in	O
December	O
1977	B-Application
.	O
</s>
<s>
But	O
due	O
to	O
production	O
delays	O
,	O
the	O
units	O
were	O
first	O
released	O
to	O
stores	O
in	O
April	O
1978	B-Application
and	O
its	O
branding	O
changed	O
to	O
"	O
Bally	B-Device
Professional	I-Device
Arcade	I-Device
"	O
.	O
</s>
<s>
The	O
Astrocade	B-Device
is	O
particularly	O
notable	O
for	O
its	O
very	O
powerful	O
graphics	O
capabilities	O
for	O
the	O
time	O
of	O
release	O
,	O
and	O
for	O
the	O
difficulty	O
in	O
accessing	O
those	O
capabilities	O
.	O
</s>
<s>
The	O
system	O
Nutting	O
delivered	O
was	O
used	O
in	O
most	O
of	O
Midway	O
's	O
classic	O
arcade	O
games	O
of	O
the	O
era	O
,	O
including	O
Gorf	B-Application
and	O
Wizard	B-Application
of	I-Application
Wor	I-Application
.	O
</s>
<s>
The	O
chip	O
set	O
supported	O
what	O
was	O
at	O
that	O
time	O
relatively	O
high	O
resolution	O
of	O
320×204	O
in	O
four	O
colours	O
per	O
line	O
,	O
although	O
to	O
access	O
this	O
mode	O
required	O
memory	O
that	O
could	O
be	O
accessed	O
at	O
a	O
faster	O
rate	O
than	O
the	O
common	O
2MHz	O
dynamic	O
RAM	B-Architecture
of	O
the	O
era	O
.	O
</s>
<s>
Originally	O
referred	O
to	O
as	O
the	O
Bally	O
Home	B-Device
Library	I-Device
Computer	I-Device
,	O
it	O
was	O
released	O
in	O
1977	B-Application
but	O
available	O
only	O
through	O
mail	O
order	O
.	O
</s>
<s>
Delays	O
in	O
the	O
production	O
meant	O
none	O
of	O
the	O
units	O
actually	O
shipped	O
until	O
1978	B-Application
,	O
and	O
by	O
this	O
time	O
the	O
machine	O
had	O
been	O
renamed	O
the	O
Bally	B-Device
Professional	I-Device
Arcade	I-Device
.	O
</s>
<s>
In	O
this	O
form	O
it	O
sold	O
mostly	O
at	O
computer	O
stores	O
and	O
had	O
little	O
retail	O
exposure	O
(	O
unlike	O
the	O
Atari	B-General_Concept
VCS	I-General_Concept
)	O
.	O
</s>
<s>
In	O
1979	B-Application
,	O
Bally	O
grew	O
less	O
interested	O
in	O
the	O
arcade	O
market	O
and	O
decided	O
to	O
sell	O
off	O
their	O
Consumer	O
Products	O
Division	O
,	O
including	O
development	O
and	O
production	O
of	O
the	O
game	O
console	O
.	O
</s>
<s>
At	O
about	O
the	O
same	O
time	O
,	O
a	O
third-party	O
group	O
had	O
been	O
unsuccessfully	O
attempting	O
to	O
bring	O
their	O
own	O
console	O
design	O
to	O
market	O
as	O
the	O
Astrovision	B-Device
.	O
</s>
<s>
In	O
1981	B-Application
they	O
re-released	O
the	O
unit	O
with	O
the	O
BASIC	O
cartridge	B-Protocol
included	O
for	O
free	O
,	O
this	O
time	O
known	O
as	O
the	O
Bally	O
Computer	O
System	O
,	O
with	O
the	O
name	O
changing	O
again	O
,	O
in	O
1982	B-Application
,	O
to	O
Astrocade	B-Device
.	O
</s>
<s>
Midway	O
had	O
long	O
been	O
planning	O
to	O
release	O
an	O
expansion	O
system	O
for	O
the	O
unit	O
,	O
known	O
as	O
the	O
ZGRASS-100	O
.	O
</s>
<s>
Midway	O
felt	O
that	O
such	O
a	O
system	O
,	O
in	O
an	O
external	O
box	O
,	O
would	O
make	O
the	O
Astrocade	B-Device
more	O
interesting	O
to	O
the	O
market	O
.	O
</s>
<s>
A	O
small	O
handful	O
may	O
have	O
been	O
produced	O
as	O
the	O
ZGRASS-32	O
after	O
the	O
machine	O
was	O
re-released	O
by	O
Astrovision	B-Device
.	O
</s>
<s>
The	O
system	O
,	O
combined	O
into	O
a	O
single	O
box	O
,	O
would	O
eventually	O
be	O
released	O
as	O
the	O
Datamax	B-Device
UV-1	I-Device
.	O
</s>
<s>
These	O
were	O
offered	O
for	O
sale	O
some	O
time	O
between	O
1980	O
and	O
1982	B-Application
,	O
but	O
it	O
is	O
unknown	O
how	O
many	O
were	O
built	O
.	O
</s>
<s>
The	O
basic	O
system	O
was	O
powered	O
by	O
a	O
Zilog	B-General_Concept
Z80	I-General_Concept
driving	O
the	O
display	O
chip	O
with	O
a	O
RAM	B-Architecture
buffer	O
in	O
between	O
the	O
two	O
.	O
</s>
<s>
This	O
sort	O
of	O
color/resolution	O
was	O
normally	O
beyond	O
the	O
capabilities	O
of	O
RAM	B-Architecture
of	O
the	O
era	O
,	O
which	O
could	O
not	O
read	O
out	O
the	O
data	O
fast	O
enough	O
to	O
keep	O
up	O
with	O
the	O
TV	O
display	O
.	O
</s>
<s>
On	O
the	O
Astrocade	B-Device
the	O
pins	O
needed	O
to	O
use	O
this	O
"	O
trick	O
"	O
were	O
not	O
connected	O
.	O
</s>
<s>
Thus	O
the	O
Astrocade	B-Device
system	O
was	O
left	O
with	O
just	O
the	O
lower	O
resolution	O
160	O
×	O
102	O
mode	O
.	O
</s>
<s>
In	O
this	O
mode	O
the	O
system	O
used	O
up	O
160	O
×	O
102	O
×	O
2bits	O
=	O
4080	O
bytes	B-Application
of	O
memory	O
to	O
hold	O
the	O
screen	O
.	O
</s>
<s>
Since	O
the	O
machine	O
had	O
only	O
4kiB	O
(	O
4096	O
bytes	B-Application
)	O
of	O
RAM	B-Architecture
,	O
this	O
left	O
very	O
little	O
room	O
for	O
program	O
functions	O
such	O
as	O
keeping	O
score	O
and	O
game	O
options	O
.	O
</s>
<s>
The	O
rest	O
of	O
the	O
program	O
would	O
have	O
to	O
be	O
placed	O
in	O
ROM	B-Device
.	O
</s>
<s>
The	O
Astrocade	B-Device
used	O
color	O
registers	O
,	O
or	O
color	O
indirection	O
,	O
so	O
the	O
four	O
colors	O
could	O
be	O
picked	O
from	O
a	O
palette	O
of	O
256	O
colors	O
.	O
</s>
<s>
Color	O
animation	O
was	O
possible	O
by	O
changing	O
the	O
values	O
of	O
the	O
registers	O
,	O
and	O
using	O
a	O
horizontal	B-General_Concept
blank	I-General_Concept
interrupt	I-General_Concept
they	O
could	O
be	O
changed	O
from	O
line	O
to	O
line	O
.	O
</s>
<s>
Unlike	O
the	O
VCS	O
,	O
the	O
Astrocade	B-Device
did	O
not	O
include	O
hardware	O
sprite	O
support	O
.	O
</s>
<s>
It	O
did	O
,	O
however	O
,	O
include	O
a	O
blitter-like	O
system	O
and	O
software	O
to	O
drive	O
it	O
.	O
</s>
<s>
Memory	O
above	O
0x4000	O
was	O
dedicated	O
to	O
the	O
display	O
,	O
and	O
memory	O
below	O
that	O
to	O
the	O
ROM	B-Device
.	O
</s>
<s>
If	O
a	O
program	O
wrote	O
to	O
the	O
ROM	B-Device
space	O
(	O
normally	O
impossible	O
,	O
it	O
is	O
"	O
read	O
only	O
"	O
after	O
all	O
)	O
the	O
video	O
chip	O
would	O
take	O
the	O
data	O
,	O
apply	O
a	O
function	O
to	O
it	O
,	O
and	O
then	O
copy	O
the	O
result	O
into	O
the	O
corresponding	O
location	O
in	O
the	O
RAM	B-Architecture
.	O
</s>
<s>
Which	O
function	O
to	O
use	O
was	O
stored	O
in	O
a	O
register	B-General_Concept
in	O
the	O
display	O
chip	O
,	O
and	O
included	O
common	O
instructions	O
like	O
XOR	O
and	O
bit-shift	O
.	O
</s>
<s>
This	O
allowed	O
the	O
Astrocade	B-Device
to	O
support	O
any	O
number	O
of	O
sprite-like	O
objects	O
independent	O
of	O
hardware	O
,	O
with	O
the	O
downside	O
that	O
it	O
was	O
up	O
to	O
the	O
software	O
to	O
re-draw	O
them	O
when	O
they	O
moved	O
.	O
</s>
<s>
The	O
Astrocade	B-Device
was	O
one	O
of	O
the	O
early	O
cartridge-based	O
systems	O
,	O
using	O
cartridges	B-Protocol
known	O
as	O
Videocades	O
that	O
were	O
designed	O
to	O
be	O
as	O
close	O
in	O
size	O
and	O
shape	O
as	O
possible	O
to	O
a	O
cassette	B-Device
tape	I-Device
.	O
</s>
<s>
The	O
unit	O
also	O
included	O
two	O
games	O
built	O
into	O
the	O
ROM	B-Device
,	O
Gunfight	B-Application
and	O
Checkmate	O
,	O
along	O
with	O
the	O
simple	O
but	O
useful	O
Calculator	O
and	O
a	O
"	O
doodle	O
"	O
program	O
called	O
Scribbling	O
.	O
</s>
<s>
Most	O
cartridges	B-Protocol
included	O
two	O
games	O
,	O
and	O
when	O
they	O
were	O
inserted	O
the	O
machine	O
would	O
reset	O
and	O
display	O
a	O
menu	O
starting	O
with	O
the	O
programs	O
on	O
the	O
cartridge	B-Protocol
and	O
then	O
listing	O
the	O
four	O
built-in	O
programs	O
.	O
</s>
<s>
The	O
Astrocade	B-Device
featured	O
a	O
relatively	O
complex	O
input	O
device	O
incorporating	O
several	O
types	O
of	O
control	O
mechanisms	O
:	O
the	O
controller	O
was	O
shaped	O
as	O
a	O
pistol-style	O
grip	O
with	O
trigger	O
switch	O
on	O
the	O
front	O
;	O
a	O
small	O
4-switch/8	O
-way	O
joystick	B-Device
was	O
placed	O
on	O
top	O
of	O
the	O
grip	O
,	O
and	O
the	O
shaft	O
of	O
the	O
joystick	B-Device
connected	O
to	O
a	O
potentiometer	B-Device
,	O
meaning	O
that	O
the	O
stick	O
could	O
be	O
rotated	O
to	O
double	O
as	O
a	O
paddle	O
controller	O
.	O
</s>
<s>
One	O
oddity	O
was	O
that	O
the	O
top	O
rear	O
of	O
the	O
unit	O
was	O
empty	O
,	O
and	O
could	O
be	O
opened	O
to	O
store	O
up	O
to	O
15	O
cartridges	B-Protocol
.	O
</s>
<s>
The	O
system	O
's	O
ability	O
to	O
be	O
upgraded	O
from	O
a	O
video	B-Device
game	I-Device
console	I-Device
to	O
personal	B-Device
computer	I-Device
along	O
with	O
its	O
library	O
of	O
nearly	O
30	O
games	O
in	O
1982	B-Application
are	O
some	O
reasons	O
that	O
made	O
it	O
more	O
versatile	O
than	O
its	O
main	O
competitors	O
,	O
and	O
was	O
listed	O
by	O
Jeff	O
Rovin	O
as	O
one	O
of	O
the	O
seven	O
major	O
video	O
game	O
suppliers	O
.	O
</s>
<s>
The	O
Astrocade	B-Device
also	O
included	O
a	O
BASIC	O
programming	O
language	O
cartridge	B-Protocol
,	O
written	O
by	O
Jamie	O
Fenton	O
,	O
who	O
expanded	O
Li-Chen	O
Wang	O
's	O
Palo	O
Alto	O
Tiny	O
BASIC	O
.	O
</s>
<s>
First	O
published	O
as	O
Bally	O
BASIC	O
in	O
1978	B-Application
.	O
</s>
<s>
Developing	O
a	O
BASIC	B-Language
interpreter	I-Language
on	O
the	O
system	O
was	O
difficult	O
,	O
because	O
the	O
display	O
alone	O
used	O
up	O
almost	O
all	O
the	O
available	O
RAM	B-Architecture
.	O
</s>
<s>
The	O
solution	O
to	O
this	O
problem	O
was	O
to	O
store	O
the	O
BASIC	O
program	O
code	O
in	O
the	O
video	O
RAM	B-Architecture
.	O
</s>
<s>
The	O
interpreter	B-Application
would	O
read	O
out	O
two	O
bytes	B-Application
,	O
drop	O
all	O
the	O
odd-numbered	O
bits	O
,	O
and	O
assemble	O
the	O
results	O
into	O
a	O
single	O
byte	B-Application
of	O
code	O
.	O
</s>
<s>
This	O
managed	O
to	O
squeeze	O
out	O
1760	O
bytes	B-Application
of	O
RAM	B-Architecture
for	O
BASIC	O
programs	O
.	O
</s>
<s>
An	O
Astro	O
BASIC	O
program	O
that	O
later	O
became	O
commercialized	O
is	O
Artillery	B-Application
Duel	I-Application
.	O
</s>
<s>
Perkins	O
subsequently	O
developed	O
the	O
Astrocade	B-Device
cartridge	B-Protocol
of	O
the	O
game	O
.	O
</s>
<s>
Certain	O
commands	O
were	O
handled	O
by	O
the	O
keypad	O
instead	O
of	O
by	O
keywords	O
:	O
the	O
RESET	O
button	O
was	O
equivalent	O
to	O
NEW	O
in	O
other	O
interpreters	B-Application
.	O
</s>
<s>
The	O
language	O
lacked	O
a	O
DIM	O
statement	O
for	O
dimensioning	O
the	O
arrays	O
,	O
the	O
size	O
of	O
which	O
was	O
determined	O
by	O
available	O
memory	O
(	O
SZ	O
)	O
not	O
used	O
by	O
the	O
program	O
listing	O
(	O
2	O
bytes	B-Application
per	O
item	O
)	O
.	O
</s>
<s>
Ports	O
were	O
accessed	O
via	O
the	O
array	O
&( 	O
)	O
,	O
and	O
memory	O
was	O
accessed	O
via	O
the	O
array	O
%( 	O
)	O
,	O
rather	O
than	O
using	O
PEEK	B-Language
and	I-Language
POKE	I-Language
.	O
</s>
<s>
While	O
the	O
language	O
lacked	O
strings	O
,	O
KP	O
would	O
provide	O
the	O
ASCII	B-Protocol
value	I-Protocol
of	O
a	O
key	O
press	O
,	O
which	O
could	O
be	O
output	O
to	O
TV	O
,	O
meaning	O
that	O
characters	O
could	O
be	O
read	O
in	O
from	O
the	O
keyboard	O
,	O
stored	O
in	O
an	O
array	O
,	O
and	O
then	O
output	O
.	O
</s>
<s>
The	O
following	O
sample	O
program	O
from	O
the	O
manual	O
demonstrates	O
the	O
joystick	B-Device
input	O
and	O
graphics	O
functions	O
.	O
</s>
<s>
The	O
ZGRASS	B-Language
unit	O
sat	O
under	O
the	O
Astrocade	B-Device
and	O
turned	O
it	O
into	O
a	O
"	O
real	O
"	O
computer	O
,	O
including	O
a	O
full	O
keyboard	O
,	O
a	O
math	B-General_Concept
co-processor	I-General_Concept
(	O
FPU	B-General_Concept
)	O
,	O
32k	O
of	O
RAM	B-Architecture
,	O
and	O
a	O
new	O
32k	O
ROM	B-Device
containing	O
the	O
GRASS	B-Language
programming	I-Language
language	I-Language
(	O
sometimes	O
referred	O
to	O
as	O
GRAFIX	O
on	O
this	O
machine	O
)	O
.	O
</s>
<s>
The	O
unit	O
also	O
added	O
I/O	O
ports	O
for	O
a	O
cassette	O
and	O
floppy	B-Device
disk	I-Device
,	O
allowing	O
it	O
to	O
be	O
used	O
with	O
CP/M	B-Application
.	O
</s>
<s>
Games	O
magazine	O
included	O
Bally	O
Professional	O
Astrocade	B-Device
in	O
their	O
"	O
Top	O
100	O
Games	O
of	O
1981	B-Application
"	O
,	O
noting	O
that	O
"	O
Our	O
favorite	O
cartridges	B-Protocol
are	O
the	O
classic	O
Gunfight	B-Application
,	O
Red	O
Baron	O
air	O
war	O
,	O
and	O
Demolition	O
Derby.	O
"	O
</s>
<s>
Danny	O
Goodman	O
of	O
Creative	B-General_Concept
Computing	I-General_Concept
Video	O
&	O
Arcade	O
Games	O
stated	O
in	O
1983	O
that	O
Astrocade	B-Device
"	O
has	O
one	O
of	O
the	O
best	O
graphics	O
and	O
sound	O
packages	O
of	O
any	O
home	O
video	O
game	O
"	O
.	O
</s>
<s>
However	O
,	O
through	O
the	O
use	O
of	O
2	O
color	O
palettes	O
and	O
a	O
left/right	O
boundary	O
control	O
byte	B-Application
you	O
could	O
have	O
the	O
left	O
section	O
of	O
screen	O
(	O
this	O
could	O
be	O
the	O
play	O
field	O
)	O
use	O
1	O
set	O
of	O
colors	O
while	O
the	O
right	O
side	O
(	O
this	O
could	O
show	O
information	O
such	O
as	O
lives	O
and	O
score	O
)	O
used	O
an	O
entirely	O
different	O
set	O
of	O
colors	O
,	O
thus	O
8	O
total	O
colors	O
were	O
possible	O
.	O
</s>
