<s>
Their	O
best-known	O
products	O
were	O
the	O
Challenger	O
series	O
of	O
microcomputers	B-Architecture
and	O
Superboard	B-Device
single-board	B-Device
computers	I-Device
.	O
</s>
<s>
The	O
company	O
was	O
the	O
first	O
to	O
market	O
microcomputers	B-Architecture
with	O
hard	B-Device
disk	I-Device
drives	I-Device
in	O
1977	O
.	O
</s>
<s>
Originally	O
a	O
maker	O
of	O
electronic	O
teaching	O
aids	O
,	O
the	O
company	O
leaned	O
quickly	O
into	O
microcomputer	B-Architecture
production	O
,	O
after	O
their	O
original	O
educational	O
products	O
failed	O
in	O
the	O
marketplace	O
while	O
their	O
computer-oriented	O
products	O
sparked	O
high	O
interest	O
in	O
the	O
hobbyist	O
community	O
.	O
</s>
<s>
The	O
first	O
products	O
the	O
company	O
released	O
included	O
a	O
calculator	B-Application
that	O
also	O
taught	O
the	O
basics	O
of	O
statistics	O
and	O
a	O
single-board	O
microcomputer	B-Architecture
.	O
</s>
<s>
The	O
latter	O
,	O
called	O
the	O
Microcomputer	B-Architecture
Trainer	O
Board	O
and	O
incorporating	O
a	O
MOS	B-General_Concept
Technology	I-General_Concept
6502	I-General_Concept
microprocessor	B-Architecture
,	O
was	O
designed	O
by	O
Mike	O
,	O
inspired	O
by	O
his	O
experience	O
with	O
microprocessor-based	O
minicomputers	B-Architecture
at	O
his	O
Ohio	O
Nuclear	O
job	O
.	O
</s>
<s>
However	O
,	O
the	O
Microcomputer	B-Architecture
Trainer	O
Board	O
saw	O
high	O
demand	O
.	O
</s>
<s>
Most	O
fruitful	O
was	O
a	O
quarter-page	O
advertisement	O
in	O
an	O
early	O
issue	O
of	O
Byte	O
—	O
a	O
magazine	O
for	O
microcomputer	B-Architecture
hobbyists	O
—	O
with	O
orders	O
for	O
the	O
board	O
totaling	O
$	O
100,000	O
within	O
a	O
few	O
months	O
.	O
</s>
<s>
With	O
the	O
release	O
of	O
their	O
microcomputer	B-Architecture
systems	O
and	O
hardware	O
in	O
the	O
mid-1970s	O
,	O
Charity	O
Cheiky	O
became	O
the	O
first	O
woman	O
at	O
the	O
helm	O
of	O
a	O
personal	O
computer	O
manufacturer	O
.	O
</s>
<s>
In	O
November	O
1980	O
,	O
the	O
company	O
acquired	O
the	O
hard	B-Device
drive	I-Device
manufacturing	O
division	O
of	O
Okidata	O
in	O
Goleta	O
,	O
California	O
,	O
which	O
manufactured	O
the	O
company	O
's	O
C-D74	O
drives	O
that	O
were	O
used	O
with	O
their	O
Challenger	O
series	O
of	O
microcomputers	B-Architecture
.	O
</s>
<s>
Further	O
computer	O
systems	O
would	O
be	O
based	O
on	O
the	O
Intel	B-Device
8088	I-Device
processor	O
and	O
were	O
slated	O
to	O
be	O
installed	O
with	O
CP/M	B-Operating_System
-86	I-Operating_System
.	O
</s>
<s>
Ohio	O
Scientific	O
are	O
best	O
remembered	O
for	O
their	O
Superboard	B-Device
and	O
Challenger	O
lines	O
,	O
single-board	O
and	O
fully	O
encased	O
microcomputer	B-Architecture
systems	O
respectively	O
.	O
</s>
<s>
The	O
first	O
Superboards	B-Device
were	O
first	O
announced	O
in	O
the	O
December	O
1975	O
issue	O
Byte	O
.	O
</s>
<s>
Announced	O
later	O
,	O
but	O
probably	O
preceding	O
the	O
first	O
Superboards	B-Device
in	O
production	O
,	O
was	O
the	O
Model	O
300	O
Computer	O
Trainer	O
Board	O
,	O
which	O
features	O
an	O
MOS	B-General_Concept
Technology	I-General_Concept
6502	I-General_Concept
microprocessor	B-Architecture
and	O
128Bytes	O
of	O
RAM	B-Architecture
.	O
</s>
<s>
In	O
a	O
design	O
scheme	O
similar	O
to	O
a	O
number	O
of	O
trainer	O
boards	O
of	O
its	O
contemporary	O
,	O
a	O
number	O
of	O
slide	O
switches	O
on	O
the	O
bottom	O
of	O
the	O
board	O
connect	O
directly	O
to	O
the	O
MOS	B-General_Concept
6502	I-General_Concept
's	O
data	O
,	O
read	O
–	O
write	O
,	O
and	O
address	O
select	O
pins	O
,	O
allowing	O
the	O
microprocessor	B-Architecture
to	O
be	O
halted	O
and	O
the	O
RAM	B-Architecture
loaded	O
with	O
machine	B-Language
code	I-Language
instructions	O
.	O
</s>
<s>
A	O
row	O
of	O
LEDs	O
connected	O
in	O
series	O
with	O
each	O
line	O
of	O
the	O
6502	B-General_Concept
's	O
bus	B-General_Concept
acts	O
as	O
a	O
visual	O
representation	O
of	O
the	O
state	O
of	O
the	O
processor	O
.	O
</s>
<s>
In	O
September	O
1976	O
,	O
the	O
company	O
announced	O
the	O
Model	O
400	O
Superboard	B-Device
,	O
a	O
DIY	O
kit	O
which	O
in	O
fully	O
assembled	O
form	O
runs	O
either	O
the	O
MOS	B-General_Concept
6502	I-General_Concept
,	O
the	O
MOS	B-General_Concept
6501	I-General_Concept
,	O
or	O
the	O
Motorola	B-Device
6800	I-Device
microprocessors	B-Architecture
.	O
</s>
<s>
The	O
Model	O
400	O
Superboard	B-Device
has	O
a	O
48-line-wide	O
bus	B-General_Concept
at	O
its	O
edge	O
,	O
allowing	O
it	O
to	O
be	O
slotted	O
into	O
a	O
backplane	B-Architecture
and	O
take	O
advantage	O
of	O
a	O
number	O
of	O
expansion	O
and	O
peripheral	O
boards	O
,	O
including	O
the	O
Model	O
420	O
memory	O
expansion	O
board	O
,	O
the	O
Model	O
430	O
Super	O
I/O	B-General_Concept
board	O
,	O
and	O
the	O
Model	O
440	O
Super	O
Video	O
graphics	O
board	O
.	O
</s>
<s>
The	O
Model	O
400	O
can	O
be	O
outfit	O
with	O
up	O
to	O
1kB	O
of	O
RAM	B-Architecture
,	O
512Bytes	O
of	O
ROM	B-General_Concept
,	O
an	O
ACIA	B-Architecture
chip	O
for	O
implementing	O
RS-232	O
or	O
4	O
–	O
20	O
mA	O
loop	O
interfaces	O
for	O
serial	O
communication	O
,	O
and	O
a	O
peripheral	O
device	O
adapter	O
with	O
16	O
I/O	B-General_Concept
lines	O
.	O
</s>
<s>
The	O
430	O
Super	O
I/O	B-General_Concept
board	O
provides	O
two	O
8-bit	O
DACs	O
,	O
one	O
8-bit	O
ADC	O
,	O
an	O
8-bit	O
parallel	O
port	O
,	O
and	O
a	O
number	O
of	O
serial	O
interfaces	O
for	O
terminal	B-General_Concept
and	O
teletype	O
interaction	O
and	O
data	O
storage	O
,	O
including	O
Baudot	O
,	O
ASCII	B-Protocol
,	O
FSK	O
,	O
and	O
Kansas	B-Device
City	I-Device
standard	I-Device
.	O
</s>
<s>
This	O
was	O
a	O
multiprocessor	B-Operating_System
expansion	O
board	O
kit	O
for	O
the	O
Model	O
400	O
Superboard	B-Device
that	O
greatly	O
expands	O
its	O
software	O
library	O
by	O
supporting	O
several	O
different	O
kinds	O
of	O
microprocessors	B-Architecture
,	O
including	O
the	O
Intersil	B-General_Concept
6100	I-General_Concept
(	O
a	O
microprocessor-based	O
implementation	O
of	O
DEC	O
's	O
PDP-8	B-Device
minicomputer	B-Architecture
)	O
and	O
the	O
Zilog	B-General_Concept
Z80	I-General_Concept
(	O
which	O
is	O
software-compatible	O
with	O
the	O
Intel	B-General_Concept
8080	I-General_Concept
by	O
design	O
)	O
.	O
</s>
<s>
The	O
460Z	O
supports	O
only	O
Model	O
400s	O
running	O
the	O
6502	B-General_Concept
but	O
allows	O
the	O
latter	O
to	O
fully	O
control	O
the	O
460Z	O
,	O
including	O
accessing	O
each	O
line	O
of	O
the	O
6100	B-General_Concept
and	O
Z80	B-General_Concept
and	O
setting	O
those	O
processors	O
in	O
either	O
single-stepping	O
mode	O
or	O
full-speed	O
operation	O
.	O
</s>
<s>
The	O
Model	O
400	O
with	O
the	O
Model	O
460Z	O
can	O
execute	O
code	O
for	O
multiple	O
architectures	O
by	O
interrupts	O
triggered	O
for	O
the	O
6502	B-General_Concept
to	O
relinquish	O
control	O
to	O
the	O
secondary	O
processors	O
,	O
and	O
vice	O
versa	O
.	O
</s>
<s>
The	O
6502	B-General_Concept
can	O
execute	O
code	O
for	O
itself	O
while	O
the	O
other	O
processors	O
are	O
busy	O
,	O
allowing	O
for	O
true	O
multiprocessing	B-Operating_System
.	O
</s>
<s>
With	O
the	O
460Z	O
installed	O
on	O
bus	B-General_Concept
,	O
the	O
Model	O
400	O
can	O
address	O
other	O
cards	O
only	O
by	O
mapping	O
a	O
4-KB	O
"	O
porthole	O
"	O
through	O
the	O
460Z	O
's	O
address	O
space	O
.	O
</s>
<s>
Billed	O
as	O
a	O
tabletop	O
computer	O
,	O
the	O
Challenger	O
I	O
borrowed	O
much	O
of	O
its	O
circuitry	O
from	O
the	O
Superboards	B-Device
sold	O
alongside	O
it	O
,	O
but	O
it	O
has	O
a	O
special	O
48-pin	O
S-100	B-Architecture
bus	I-Architecture
for	O
expansion	O
which	O
makes	O
use	O
of	O
non-standard	O
Molex	O
connectors	O
,	O
ostensibly	O
an	O
attempt	O
at	O
making	O
the	O
contacts	O
more	O
reliable	O
.	O
</s>
<s>
The	O
Challenger	O
I	O
has	O
four	O
of	O
these	O
special	O
S-100-bus	O
expansion	O
slots	O
.	O
</s>
<s>
Jeffrey	O
Beamsley	O
of	O
Micro	O
magazine	O
describes	O
the	O
bus	B-General_Concept
as	O
such	O
:	O
</s>
<s>
The	O
48-pin	O
Ohio	O
Scientific	O
bus	B-General_Concept
is	O
really	O
a	O
model	O
of	O
efficiency	O
.	O
</s>
<s>
The	O
defined	O
pins	O
on	O
the	O
bus	B-General_Concept
include	O
20	O
address	O
lines	O
,	O
6	O
power	O
lines	O
,	O
8	O
data	O
lines	O
,	O
and	O
8	O
control	O
lines	O
.	O
</s>
<s>
The	O
bus	B-General_Concept
supports	O
distributed	O
,	O
fully	O
regulated	O
DC	O
power	O
.	O
</s>
<s>
The	O
placement	O
of	O
the	O
power	O
lines	O
causes	O
dead	O
shorts	O
on	O
the	O
bus	B-General_Concept
for	O
any	O
board	O
improperly	O
inserted	O
.	O
</s>
<s>
The	O
Ohio	O
Scientific	O
bus	B-General_Concept
was	O
one	O
of	O
the	O
first	O
microprocessor	B-Architecture
busses	O
to	O
support	O
bi-directional	O
data	O
lines	O
.	O
</s>
<s>
It	O
is	O
very	O
inexpensive	O
as	O
far	O
as	O
bus	B-General_Concept
structures	O
are	O
concerned	O
and	O
is	O
classed	O
by	O
Ohio	O
Scientific	O
as	O
proprietary	O
.	O
</s>
<s>
As	O
stock	O
,	O
the	O
Challenger	O
came	O
with	O
a	O
1-MHz	O
MOS	O
6502A	B-General_Concept
microprocessor	B-Architecture
;	O
optional	O
were	O
a	O
4-MHz	O
MOS	O
6502C	O
and	O
a	O
Motorola	B-Device
6800	I-Device
.	O
</s>
<s>
The	O
base	O
configuration	O
of	O
the	O
Challenger	O
I	O
contains	O
1KB	O
of	O
RAM	B-Architecture
and	O
1KB	O
of	O
PROM	O
;	O
it	O
can	O
support	O
up	O
to	O
192KB	O
and	O
16KB	O
of	O
each	O
respectively	O
.	O
</s>
<s>
If	O
purchased	O
with	O
4KB	O
of	O
PROM	O
,	O
Ohio	O
Scientific	O
included	O
a	O
free	O
roll	O
of	O
Microsoft	B-Language
BASIC	I-Language
on	O
paper	O
tape	O
.	O
</s>
<s>
The	O
Challenger	O
I	O
comes	O
with	O
a	O
bootstrap	B-Operating_System
loader	I-Operating_System
built	O
in	O
to	O
the	O
machine	O
that	O
reads	O
from	O
paper	O
tape	O
readers	O
such	O
as	O
that	O
built	O
into	O
the	O
Teletype	B-Application
Model	I-Application
33	I-Application
,	O
which	O
it	O
also	O
supports	O
as	O
a	O
terminal	B-General_Concept
interface	O
due	O
to	O
its	O
inclusion	O
of	O
an	O
ACIA	B-Architecture
;	O
alternatively	O
a	O
video	B-General_Concept
terminal	I-General_Concept
can	O
be	O
used	O
.	O
</s>
<s>
By	O
mid-1977	O
a	O
medley	O
of	O
expansion	O
cards	O
and	O
peripherals	O
were	O
available	O
from	O
Ohio	O
Scientific	O
for	O
the	O
Challenger	O
I	O
,	O
including	O
a	O
single	O
or	O
dual	O
floppy	B-Device
disk	I-Device
drives	I-Device
(	O
manufactured	O
by	O
GSI	O
in	O
California	O
)	O
,	O
a	O
cassette	O
drive	O
and	O
interface	O
,	O
a	O
video	O
card	O
,	O
and	O
an	O
external	O
keyboard	O
.	O
</s>
<s>
In	O
January	O
1978	O
,	O
Ohio	O
Scientific	O
began	O
the	O
Challenger	O
I	O
as	O
part	O
of	O
an	O
integrated	O
bundle	O
,	O
including	O
a	O
custom	O
video	B-General_Concept
terminal	I-General_Concept
using	O
a	O
Sanyo-manufactured	O
CRT	B-Device
,	O
a	O
rebranded	O
GSI	O
110	O
single	O
floppy	B-Device
drive	I-Device
,	O
and	O
one	O
of	O
two	O
Okidata	O
dot-matrix	O
printers	O
.	O
</s>
<s>
Kilobaud	O
Microcomputing	B-Architecture
called	O
the	O
Challenger	O
I	O
"	O
the	O
first	O
fully	O
assembled	O
mainframe	O
computer	O
which	O
is	O
priced	O
competitively	O
with	O
hobby	O
kits	O
"	O
.	O
</s>
<s>
The	O
Ohio	O
Scientific	O
Model	O
500	O
—	O
available	O
as	O
either	O
a	O
single-board	B-Device
computer	I-Device
,	O
as	O
a	O
small-form-factor	B-Device
desktop	B-Device
computer	I-Device
(	O
as	O
the	O
Model	O
500-1	O
)	O
,	O
or	O
as	O
a	O
keyboard	B-Device
computer	I-Device
(	O
as	O
the	O
Model	O
500-8	O
)	O
—	O
was	O
announced	O
on	O
July	O
1977	O
.	O
</s>
<s>
Running	O
a	O
1-MHz	O
MOS	B-General_Concept
6502	I-General_Concept
microprocessor	B-Architecture
,	O
the	O
Model	O
500	O
supports	O
up	O
to	O
4kB	O
of	O
RAM	B-Architecture
and	O
comes	O
with	O
a	O
750-byte	O
PROM	O
chip	O
containing	O
one	O
of	O
two	O
machine	B-General_Concept
code	I-General_Concept
monitors	I-General_Concept
and	O
four	O
ROM	B-General_Concept
sockets	O
supporting	O
up	O
to	O
8KB	O
worth	O
of	O
chips	O
.	O
</s>
<s>
The	O
four	O
2-KB	O
ROM	B-General_Concept
chips	O
included	O
with	O
the	O
stock	O
Model	O
500	O
were	O
manufactured	O
by	O
Signetics	O
and	O
contain	O
Microsoft	O
's	O
official	O
BASIC	B-Language
interpreter	O
,	O
occupying	O
all	O
8KB	O
of	O
ROM	B-General_Concept
.	O
</s>
<s>
The	O
Model	O
500	O
also	O
has	O
a	O
buffered	O
expansion	O
bus	B-General_Concept
and	O
an	O
Motorola	O
6850	O
UART	O
for	O
RS-232	O
and	O
current-loop	O
serial	O
communications	O
.	O
</s>
<s>
The	O
Model	O
500	O
came	O
fully	O
assembled	O
and	O
was	O
interoperable	O
with	O
Ohio	O
Scientific	O
's	O
Model	O
400	O
system	O
of	O
peripherals	O
using	O
that	O
computer	O
's	O
backplane	B-Architecture
,	O
including	O
the	O
Model	O
440	O
Super	O
Video	O
board	O
.	O
</s>
<s>
One	O
of	O
two	O
machine	B-General_Concept
code	I-General_Concept
monitors	I-General_Concept
were	O
supplied	O
:	O
one	O
configured	O
for	O
the	O
Model	O
500	O
as	O
used	O
with	O
a	O
terminal	B-General_Concept
for	O
video	O
output	O
,	O
and	O
the	O
other	O
for	O
the	O
computer	O
as	O
used	O
with	O
the	O
Model	O
440	O
Super	O
Video	O
board	O
.	O
</s>
<s>
Writing	O
in	O
Kilobaud	O
Microcomputing	B-Architecture
,	O
F.R.	O
</s>
<s>
Ruckdeschel	O
called	O
the	O
Model	O
500	O
very	O
cost	O
competitive	O
with	O
the	O
"	O
1977	O
Trinity	O
"	O
of	O
the	O
Apple	B-Device
II	I-Device
,	O
Commodore	B-Device
PET	I-Device
,	O
and	O
TRS-80	B-Device
,	O
given	O
that	O
it	O
included	O
Microsoft	B-Language
BASIC	I-Language
like	O
those	O
systems	O
while	O
costing	O
an	O
order	O
of	O
magnitude	O
less	O
.	O
</s>
<s>
However	O
,	O
he	O
deemed	O
it	O
"	O
not	O
an	O
'	O
appliance	O
 '	O
computer	O
,	O
but	O
 [ an ] 	O
interesting	O
basic	B-Language
microcomputer	B-Architecture
for	O
the	O
hobbyist	O
"	O
,	O
due	O
to	O
the	O
level	O
of	O
involvement	O
needed	O
in	O
setting	O
it	O
up	O
.	O
</s>
<s>
The	O
first	O
two	O
models	O
,	O
the	O
Challenger	O
II	O
(	O
model	O
number	O
IIV	O
,	O
later	O
C2-S2	O
)	O
and	O
the	O
Challenger	O
IIP	O
,	O
were	O
based	O
on	O
Ohio	O
Scientific	O
's	O
Model	O
500	O
single-board	B-Device
computer	I-Device
.	O
</s>
<s>
The	O
Challenger	O
IIP	O
(	O
also	O
rendered	O
as	O
2P	O
)	O
has	O
a	O
2-MHz	O
MOS	O
6502A	B-General_Concept
,	O
while	O
the	O
Challenger	O
II	O
proper	O
has	O
only	O
a	O
1-MHz	O
6502	B-General_Concept
.	O
</s>
<s>
The	O
Challenger	O
IIP	O
has	O
an	O
integral	O
keyboard	O
and	O
RF	O
video	O
output	O
board	O
but	O
only	O
four	O
of	O
Ohio	O
Scientific	O
's	O
semi-proprietary	O
S-100	O
expansion	O
bus	B-General_Concept
slots	O
.	O
</s>
<s>
The	O
II	O
proper	O
meanwhile	O
has	O
eight	O
such	O
S-100	O
slots	O
but	O
lacks	O
a	O
keyboard	O
or	O
video	O
output	O
—	O
relying	O
on	O
a	O
terminal	B-General_Concept
for	O
interaction	O
—	O
and	O
is	O
built	O
into	O
a	O
desktop	O
form	O
factor	O
.	O
</s>
<s>
Both	O
Challengers	O
came	O
shipped	O
with	O
Microsoft	B-Language
BASIC	I-Language
(	O
the	O
IIP	O
's	O
was	O
included	O
in	O
ROM	B-General_Concept
)	O
,	O
had	O
4KB	O
of	O
RAM	B-Architecture
,	O
and	O
were	O
compatible	O
with	O
all	O
Challenger	O
I	O
software	O
.	O
</s>
<s>
This	O
was	O
an	O
external	O
hard	B-Device
drive	I-Device
unit	O
that	O
used	O
a	O
14-inch	O
74-MB	O
hard	B-Device
disk	I-Device
drive	I-Device
sourced	O
from	O
Okidata	O
.	O
</s>
<s>
A	O
Winchester-style	O
hard	B-Device
disk	I-Device
drive	I-Device
,	O
it	O
was	O
the	O
first	O
such	O
drive	O
with	O
12	O
tracks	O
per	O
cylinder	O
,	O
no	O
head	O
reseeking	O
needed	O
.	O
</s>
<s>
Ohio	O
Scientific	O
quoted	O
a	O
data	O
transfer	O
rate	O
of	O
7.3Mbit/s	O
,	O
an	O
access	B-General_Concept
time	I-General_Concept
of	O
5	O
,	O
a	O
single-track	O
seek	O
time	O
of	O
10ms	O
,	O
and	O
an	O
average	O
random	O
seek	O
time	O
of	O
35ms	O
.	O
</s>
<s>
Ohio	O
Scientific	O
was	O
the	O
first	O
company	O
to	O
offer	O
a	O
microcomputer	B-Architecture
with	O
hard	B-Device
drives	I-Device
.	O
</s>
<s>
Variants	O
of	O
the	O
II	O
and	O
IIP	O
with	O
external	O
8-inch	B-Device
floppy	I-Device
disk	O
drive	O
units	O
were	O
introduced	O
in	O
April	O
1978	O
.	O
</s>
<s>
Ohio	O
Systems	O
issued	O
a	O
external	O
dual	O
5.25-inch	O
floppy	B-Device
drive	I-Device
unit	O
for	O
the	O
Challenger	O
II	O
by	O
1979	O
.	O
</s>
<s>
Starting	O
in	O
September	O
1977	O
,	O
Ohio	O
Scientific	O
shipped	O
all	O
Challenger	O
systems	O
ordered	O
with	O
floppy	B-Device
disk	I-Device
drives	I-Device
with	O
OS-65D	O
,	O
the	O
company	O
's	O
own	O
disk	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
which	O
included	O
the	O
filesystem	O
,	O
BASIC	B-Language
,	O
an	O
assembler	O
,	O
a	O
disassembler	O
,	O
a	O
line	B-Application
editor	I-Application
,	O
and	O
an	O
extended	O
debugger	O
.	O
</s>
<s>
Through	O
the	O
use	O
of	O
overlays	B-General_Concept
,	O
OS-65D	O
never	O
occupies	O
more	O
than	O
12kB	O
of	O
RAM	B-Architecture
.	O
</s>
<s>
It	O
supports	O
dual	O
drive	O
configurations	O
and	O
sequential	O
and	O
random	O
file	O
access	O
,	O
while	O
its	O
BASIC	B-Language
implementation	O
allows	O
linked	B-Application
code	O
.	O
</s>
<s>
It	O
was	O
a	O
desktop	B-Device
computer	I-Device
featuring	O
three	O
microprocessors	B-Architecture
—	O
a	O
MOS	O
6502A	B-General_Concept
,	O
a	O
Zilog	B-General_Concept
Z80	I-General_Concept
,	O
and	O
a	O
Motorola	B-Device
6800	I-Device
—	O
on	O
one	O
board	O
.	O
</s>
<s>
This	O
combination	O
of	O
processors	O
allowed	O
the	O
computer	O
to	O
run	O
virtually	O
all	O
software	O
for	O
microcomputers	B-Architecture
on	O
the	O
market	O
at	O
the	O
time	O
of	O
its	O
release	O
.	O
</s>
<s>
An	O
external	O
,	O
single-sided	O
(	O
later	O
double-sided	O
)	O
,	O
dual	O
8-inch	B-Device
floppy	I-Device
drive	O
unit	O
was	O
available	O
for	O
the	O
Challenger	O
III	O
,	O
as	O
was	O
the	O
C-D74	O
hard	B-Device
drive	I-Device
unit	O
.	O
</s>
<s>
Ohio	O
Scientific	O
was	O
keen	O
to	O
match	O
the	O
Challenger	O
III	O
with	O
the	O
C-D74	O
,	O
offering	O
both	O
in	O
a	O
74-inch	O
tall	O
rack-mount	O
case	O
as	O
a	O
complete	O
system	O
christened	O
the	O
C3-B	O
—	O
the	O
first	O
microcomputer	B-Architecture
system	O
to	O
include	O
a	O
hard	B-Device
drive	I-Device
.	O
</s>
<s>
To	O
this	O
end	O
,	O
Ohio	O
Scientific	O
provided	O
a	O
serial	O
I/O	B-General_Concept
board	O
called	O
the	O
CA-10	O
,	O
allowing	O
up	O
up	O
to	O
sixteen	O
terminals	O
to	O
connect	O
to	O
the	O
Challenger	O
III	O
.	O
</s>
<s>
A	O
version	O
of	O
the	O
Challenger	O
III	O
with	O
integrated	O
CA-10	O
and	O
dual	O
8-inch	B-Device
floppy	I-Device
drives	O
(	O
but	O
without	O
the	O
integral	O
keyboard	O
)	O
was	O
introduced	O
as	O
the	O
C3-OEM	O
in	O
late	O
1978	O
.	O
</s>
<s>
Released	O
in	O
fall	O
1978	O
,	O
the	O
Superboard	B-Device
II	O
featured	O
a	O
MOS	B-General_Concept
6502	I-General_Concept
,	O
8KB	O
BASIC	B-Language
in	O
ROM	B-General_Concept
,	O
a	O
BIOS	O
and	O
machine	B-General_Concept
code	I-General_Concept
monitor	I-General_Concept
in	O
separate	O
ROM	B-General_Concept
,	O
8KB	O
of	O
static	B-Architecture
RAM	I-Architecture
,	O
a	O
cassette	O
interface	O
,	O
and	O
,	O
most	O
notably	O
,	O
a	O
built-in	O
keyboard	O
soldered	O
to	O
the	O
board	O
.	O
</s>
<s>
Ohio	O
Scientific	O
billed	O
it	O
as	O
the	O
first	O
microcomputer	B-Architecture
integrated	O
onto	O
one	O
single	O
circuit	O
board	O
,	O
owing	O
to	O
the	O
soldered-on	O
keyboard	O
.	O
</s>
<s>
The	O
company	O
introduced	O
it	O
alongside	O
the	O
Challenger	O
1P	O
,	O
essentially	O
the	O
same	O
as	O
the	O
Superboard	B-Device
II	O
but	O
enclosed	O
in	O
a	O
case	O
and	O
including	O
a	O
power	O
supply	O
.	O
</s>
<s>
Optional	O
for	O
each	O
were	O
an	O
24KB	O
expansion	O
RAM/Floppy	O
Disk	O
Drive	O
Interface	O
board	O
,	O
for	O
supporting	O
an	O
external	O
dual	O
5.25-inch	O
floppy	B-Device
drive	I-Device
as	O
well	O
as	O
a	O
printer	O
or	O
modem	O
.	O
</s>
<s>
The	O
entire	O
Superboard	B-Device
II	O
measures	O
.	O
</s>
<s>
A	O
clone	O
of	O
the	O
Superboard	B-Device
II	O
was	O
sold	O
in	O
the	O
United	O
Kingdom	O
as	O
the	O
Compukit	B-Device
UK101	I-Device
.	O
</s>
<s>
Bruce	O
S	O
.	O
Chamberlain	O
,	O
writing	O
in	O
Kilobyte	O
Microcomputing	B-Architecture
,	O
praised	O
the	O
Superboard	B-Device
II	O
's	O
BASIC	B-Language
interpreter	O
for	O
its	O
speed	O
and	O
called	O
the	O
system	O
overall	O
"	O
less	O
expensive	O
than	O
comparable	O
systems	O
"	O
and	O
"	O
the	O
best	O
buy	O
available	O
for	O
both	O
beginner	O
and	O
expert	O
.	O
</s>
<s>
The	O
Challenger	O
4P	O
(	O
4P	O
MF	O
)	O
,	O
released	O
in	O
late	O
1979	O
,	O
was	O
a	O
keyboard	B-Device
computer	I-Device
like	O
the	O
Challenger	O
IIP	O
.	O
</s>
<s>
Like	O
all	O
Challengers	O
before	O
it	O
,	O
the	O
4P	O
ran	O
off	O
a	O
6502	B-General_Concept
microprocessor	I-General_Concept
.	O
</s>
<s>
The	O
computer	O
came	O
with	O
24KB	O
of	O
RAM	B-Architecture
stock	O
,	O
expandable	O
to	O
48KB	O
.	O
</s>
<s>
The	O
computer	O
came	O
stock	O
with	O
Microsoft	O
8K	O
BASIC	B-Language
IN	O
ROM	B-General_Concept
,	O
and	O
8KB	O
of	O
Static	B-Architecture
RAM	I-Architecture
,	O
and	O
it	O
could	O
have	O
been	O
expanded	O
to	O
have	O
the	O
home	O
automation	O
features	O
of	O
the	O
4P	O
with	O
the	O
purchase	O
of	O
630/10	O
expansion	O
card	O
.	O
</s>
<s>
The	O
C1P	O
MF	O
was	O
a	O
variant	O
of	O
the	O
computer	O
that	O
came	O
packaged	O
with	O
a	O
dual	O
5.25-inch	O
floppy	B-Device
drive	I-Device
unit	O
and	O
OS-MDMS	O
,	O
a	O
small	O
database	O
management	O
system	O
.	O
</s>
