<s>
The	O
Dimension	B-Device
68000	I-Device
is	O
a	O
microcomputer	B-Architecture
introduced	O
by	O
the	O
Micro	B-Device
Craft	I-Device
Corporation	I-Device
in	O
1983	O
that	O
sought	O
to	O
emulate	O
the	O
Apple	B-Device
II	I-Device
,	O
the	O
IBM	B-Device
PC	I-Device
,	O
and	O
various	O
CP/M	B-Application
-centric	O
computers	O
through	O
a	O
family	O
of	O
coprocessor	O
expansion	B-Device
cards	I-Device
and	O
emulation	O
software	O
.	O
</s>
<s>
The	O
Dimension	B-Device
68000	I-Device
can	O
also	O
run	O
as	O
a	O
standalone	O
computer	O
based	O
on	O
the	O
Motorola	B-Device
68000	I-Device
from	O
which	O
it	O
gets	O
its	O
namesake	O
.	O
</s>
<s>
The	O
computer	O
is	O
mostly	O
the	O
brainchild	O
of	O
Mike	O
Carpenter	O
,	O
a	O
former	O
executive	O
of	O
a	O
scientific	O
instrument	O
manufacturer	O
who	O
incorporated	O
Micro	B-Device
Craft	I-Device
in	O
Dallas	O
,	O
Texas	O
,	O
to	O
develop	O
the	O
Dimension	B-Device
68000	I-Device
.	O
</s>
<s>
The	O
Dimension	B-Device
68000	I-Device
is	O
a	O
desktop	B-Device
microcomputer	B-Architecture
whose	O
main	O
unit	O
measures	O
and	O
weighs	O
between	O
,	O
depending	O
on	O
the	O
configuration	O
.	O
</s>
<s>
Micro	B-Device
Craft	I-Device
encouraged	O
user-servicing	O
from	O
the	O
onset	O
and	O
did	O
not	O
void	O
the	O
warranty	O
of	O
purchasers	O
should	O
they	O
have	O
opened	O
the	O
case	O
,	O
as	O
was	O
an	O
increasing	O
practice	O
around	O
the	O
time	O
of	O
the	O
Dimension	O
's	O
release	O
.	O
</s>
<s>
The	O
dual	O
5.25-inch	O
floppy	B-Device
disk	I-Device
drives	I-Device
and	O
the	O
accompanying	O
full-drive-height	O
blanking	O
plate	O
of	O
the	O
stock	O
configuration	O
feature	O
black	O
trim	O
.	O
</s>
<s>
Next	O
to	O
the	O
disk	O
drives	O
is	O
a	O
reset	B-Application
button	I-Application
;	O
the	O
functionality	O
of	O
the	O
button	O
can	O
be	O
disabled	O
in	O
software	O
to	O
prevent	O
accidental	O
actuation	O
.	O
</s>
<s>
In	O
the	O
rear	O
of	O
the	O
main	O
unit	O
are	O
six	O
expansion	B-Device
card	I-Device
holes	O
which	O
may	O
be	O
populated	O
depending	O
on	O
the	O
configuration	O
(	O
all	O
six	O
are	O
populated	O
with	O
blanking	O
plates	O
in	O
stock	O
configuration	O
)	O
,	O
as	O
well	O
as	O
one	O
RS-232	O
serial	O
port	O
,	O
a	O
Centronics-style	B-Device
parallel	O
port	O
,	O
the	O
keyboard	O
port	O
,	O
a	O
joystick	B-Device
port	O
,	O
and	O
the	O
composite	O
video	O
output	O
jack	O
.	O
</s>
<s>
A	O
100-watt	O
,	O
15-amp	O
switched-mode	O
supply	O
powers	O
the	O
unit	O
and	O
was	O
described	O
by	O
Microcomputing	B-Architecture
magazine	O
as	O
"offer[ing]	O
enough	O
juice	O
to	O
power	O
just	O
about	O
any	O
board	O
you	O
'd	O
want	O
to	O
add	O
"	O
.	O
</s>
<s>
The	O
motherboard	O
of	O
the	O
Dimension	B-Device
68000	I-Device
comprises	O
a	O
four-layer	O
printed	O
circuit	O
board	O
.	O
</s>
<s>
It	O
rests	O
on	O
the	O
bottom	O
of	O
the	O
chassis	O
and	O
features	O
six	O
expansion	B-Device
slots	I-Device
.	O
</s>
<s>
Among	O
the	O
other	O
logic	O
chips	O
on	O
the	O
motherboard	O
resides	O
the	O
main	O
microprocessor	O
—	O
a	O
Motorola	B-Device
68000	I-Device
clocked	O
at	O
8MHz	O
—	O
and	O
the	O
random-access	B-Architecture
,	O
DIP	B-Algorithm
memory	B-Architecture
chips	I-Architecture
.	O
</s>
<s>
The	O
motherboard	O
accepts	O
a	O
total	O
of	O
512KB	O
of	O
RAM	B-Architecture
on	O
the	O
motherboard	O
.	O
</s>
<s>
Additional	O
RAM	B-Architecture
could	O
be	O
installed	O
only	O
on	O
expansion	B-Device
cards	I-Device
;	O
Micro	B-Device
Craft	I-Device
promised	O
a	O
memory	O
expansion	B-Device
card	I-Device
in	O
early	O
1984	O
,	O
for	O
which	O
multiple	O
orders	O
of	O
the	O
card	O
could	O
be	O
used	O
within	O
the	O
same	O
machine	O
and	O
expand	O
the	O
computer	O
's	O
memory	O
to	O
16MB	O
—	O
the	O
full	O
amount	O
of	O
RAM	B-Architecture
that	O
the	O
Motorola	B-Device
68000	I-Device
can	O
address	O
.	O
</s>
<s>
The	O
stock	O
configuration	O
of	O
the	O
Dimension	B-Device
68000	I-Device
came	O
only	O
with	O
256KB	O
of	O
RAM	B-Architecture
.	O
</s>
<s>
An	O
8-KB	O
read-only	B-Device
memory	I-Device
chip	O
holds	O
the	O
bootstrap	B-Application
code	O
,	O
the	O
Dimension	B-Device
68000	I-Device
's	O
BIOS	B-Operating_System
,	O
and	O
basic	O
diagnostic	O
utilities	O
.	O
</s>
<s>
The	O
disk	O
drives	O
of	O
the	O
stock	O
Dimension	B-Device
68000	I-Device
consist	O
of	O
two	O
half-height	O
,	O
5.25-inch	O
,	O
40-track	O
floppy	B-Device
drives	I-Device
.	O
</s>
<s>
Two	O
more	O
half-height	O
5.25-inch	O
floppy	B-Device
drives	I-Device
can	O
be	O
outfitted	O
in	O
the	O
blank	O
full-drive-height	O
space	O
to	O
the	O
right	O
,	O
or	O
one	O
full-height	O
hard	O
drive	O
can	O
be	O
installed	O
in	O
the	O
same	O
space	O
.	O
</s>
<s>
The	O
floppy	B-Device
drives	I-Device
are	O
controlled	B-Architecture
by	O
the	O
NEC	O
765	O
chip	O
,	O
a	O
versatile	O
controller	O
that	O
supports	O
numerous	O
contemporary	O
floppy	B-Device
disk	I-Device
encoding	O
schemes	O
,	O
allowing	O
it	O
to	O
read	O
and	O
format	O
disks	O
for	O
the	O
computer	O
's	O
IBM	B-Device
PC	I-Device
and	O
CP/M	B-Application
-80	I-Application
emulation	O
modes	O
.	O
</s>
<s>
The	O
Apple	B-Device
II	I-Device
emulation	O
mode	O
required	O
its	O
own	O
unique	O
floppy	B-Device
controller	O
on	O
the	O
Apple	B-Device
II	I-Device
coprocessor	O
card	O
(	O
see	O
§	O
Coprocessor	O
cards	O
)	O
.	O
</s>
<s>
Hard	O
drives	O
also	O
required	O
their	O
own	O
controllers	O
,	O
included	O
on	O
expansion	B-Device
cards	I-Device
sold	O
by	O
Micro	B-Device
Craft	I-Device
with	O
the	O
drive	O
or	O
should	O
the	O
computer	O
have	O
been	O
optioned	O
with	O
one	O
;	O
this	O
controller	O
card	O
was	O
not	O
available	O
in	O
the	O
first	O
few	O
months	O
of	O
the	O
Dimension	B-Device
68000	I-Device
's	O
market	O
availability	O
.	O
</s>
<s>
A	O
utility	O
included	O
in	O
the	O
system	O
disk	O
also	O
allows	O
the	O
floppy	B-Device
drives	I-Device
to	O
read	O
disks	O
formatted	O
in	O
IBM	B-Operating_System
PC	I-Operating_System
CP/M	I-Operating_System
,	O
the	O
TRS-80	B-Device
range	O
,	O
all	O
of	O
Kaypro	O
's	O
computers	O
,	O
and	O
single-density	O
drives	O
used	O
by	O
Cromemco	O
and	O
Osborne	O
computers	O
.	O
</s>
<s>
It	O
did	O
come	O
packaged	O
with	O
a	O
keyboard	O
,	O
built	O
by	O
Key	O
Tronic	O
and	O
which	O
features	O
the	O
same	O
layout	O
and	O
interface	O
as	O
the	O
keyboard	B-Device
for	I-Device
the	I-Device
IBM	I-Device
PC	I-Device
and	I-Device
PC	I-Device
XT	I-Device
.	O
</s>
<s>
An	O
RGB	O
expansion	B-Device
card	I-Device
for	O
digital	O
component	O
video	O
output	O
was	O
introduced	O
sometime	O
between	O
July	O
1984	O
and	O
April	O
1985	O
.	O
</s>
<s>
The	O
Dimension	B-Device
68000	I-Device
's	O
coprocessor	O
expansion	B-Device
cards	I-Device
were	O
the	O
main	O
draw	O
of	O
the	O
computer	O
because	O
it	O
promised	O
a	O
cross-platform	O
experience	O
in	O
one	O
unit	O
.	O
</s>
<s>
Regardless	O
,	O
purchasers	O
could	O
have	O
ordered	O
a	O
Dimension	B-Device
68000	I-Device
without	O
any	O
cards	O
and	O
have	O
it	O
still	O
be	O
functional	O
as	O
a	O
68000-based	O
computer	O
,	O
albeit	O
with	O
a	O
limited	O
selection	O
of	O
turnkey	O
applications	O
.	O
</s>
<s>
The	O
Dimension	B-Device
68000	I-Device
's	O
expansion	B-Device
bus	I-Device
is	O
of	O
Micro	B-Device
Craft	I-Device
's	O
own	O
proprietary	O
design	O
,	O
although	O
its	O
specification	O
was	O
open	O
to	O
prospective	O
third-party	O
manufacturers	O
,	O
as	O
well	O
as	O
a	O
development-kit	O
version	O
of	O
the	O
computer	O
with	O
a	O
prototyping	O
perfboard	O
included	O
.	O
</s>
<s>
The	O
bus	O
connectors	O
are	O
86	O
pins	O
wide	O
,	O
allowing	O
access	O
to	O
the	O
computer	O
's	O
16-bit	O
data	O
path	O
,	O
24-bit	O
address	O
lines	O
,	O
and	O
the	O
Motorola	B-Device
68000	I-Device
's	O
major	O
and	O
memory-access	O
signals	O
,	O
as	O
well	O
as	O
providing	O
individual	O
direct	B-General_Concept
memory	I-General_Concept
access	I-General_Concept
and	O
interrupt	B-Application
capabilities	O
for	O
each	O
slot	O
.	O
</s>
<s>
The	O
bus	O
also	O
conveys	O
all	O
disk	O
drive	O
signals	O
,	O
allowing	O
expansion	B-Device
cards	I-Device
to	O
equip	O
disk	O
controllers	O
besides	O
the	O
built-in	O
NEC	O
765	O
;	O
such	O
is	O
the	O
case	O
with	O
the	O
Apple	B-Device
II	I-Device
coprocessor	O
card	O
.	O
</s>
<s>
The	O
Dimension	B-Device
68000	I-Device
was	O
described	O
as	O
a	O
"	O
hybrid	O
emulator	O
"	O
—	O
that	O
is	O
,	O
each	O
of	O
the	O
coprocessors	O
performed	O
the	O
bulk	O
of	O
code	O
execution	O
in	O
their	O
respective	O
emulation	O
modes	O
,	O
while	O
certain	O
memory-resident	O
programs	O
handled	O
elements	O
of	O
emulation	O
in	O
the	O
background	O
.	O
</s>
<s>
The	O
Motorola	B-Device
68000	I-Device
additionally	O
handled	O
certain	O
interrupts	B-Application
the	O
coprocessors	O
by	O
themselves	O
could	O
not	O
execute	O
—	O
chiefly	O
regarding	O
display	O
output	O
and	O
disk	O
reading	O
and	O
writing	O
.	O
</s>
<s>
From	O
its	O
inception	O
through	O
to	O
its	O
demise	O
,	O
Micro	B-Device
Craft	I-Device
only	O
offered	O
three	O
expansion	B-Device
cards	I-Device
for	O
the	O
Dimension	B-Device
68000	I-Device
—	O
an	O
IBM	B-Device
PC	I-Device
emulation	O
card	O
,	O
an	O
Apple	B-Device
II	I-Device
emulation	O
card	O
,	O
and	O
a	O
CP/M	B-Application
card	O
for	O
Zilog	B-General_Concept
Z80	I-General_Concept
–	O
based	O
machines	O
such	O
as	O
the	O
Kaypro	O
and	O
Osborne	B-Device
1	I-Device
.	O
</s>
<s>
In	O
order	O
to	O
use	O
any	O
of	O
these	O
emulation	O
cards	O
,	O
an	O
"	O
emulation	O
master	O
"	O
disk	O
comprising	O
the	O
specific	O
files	O
included	O
in	O
the	O
master	O
system	O
disk	O
had	O
to	O
be	O
written	O
to	O
a	O
user	O
's	O
spare	O
floppy	B-Device
disk	I-Device
,	O
in	O
a	O
process	O
outlined	O
in	O
the	O
copy	O
utility	O
included	O
in	O
the	O
master	O
disk	O
and	O
in	O
the	O
Dimension	B-Device
68000	I-Device
's	O
manual	O
.	O
</s>
<s>
The	O
user	O
then	O
has	O
to	O
insert	O
the	O
system	O
disk	O
into	O
drive	O
A	O
and	O
the	O
"	O
emulation	O
master	O
"	O
disk	O
into	O
drive	O
B	O
and	O
type	O
into	O
the	O
default	O
system	O
prompt	O
,	O
e.g.	O
,	O
,	O
to	O
boot	O
into	O
the	O
IBM	B-Device
PC	I-Device
emulation	O
mode	O
.	O
</s>
<s>
Both	O
disks	O
could	O
then	O
be	O
removed	O
from	O
the	O
drives	O
,	O
and	O
specific	O
IBM	B-Device
PC	I-Device
software	O
can	O
be	O
loaded	O
from	O
disk	O
.	O
</s>
<s>
The	O
Apple	B-Device
II	I-Device
coprocessor	O
card	O
runs	O
off	O
an	O
MOS	O
6512	O
,	O
as	O
opposed	O
to	O
the	O
real	O
Apple	B-Device
II	I-Device
's	O
MOS	B-General_Concept
6502	I-General_Concept
,	O
because	O
of	O
the	O
former	O
's	O
reliance	O
on	O
an	O
external	O
clock	O
generator	O
—	O
a	O
setup	O
better	O
suited	O
for	O
multiprocessor	O
arrangements	O
such	O
as	O
the	O
Dimension	B-Device
68000	I-Device
.	O
</s>
<s>
A	O
bespoke	O
floppy	B-Device
controller	O
is	O
also	O
included	O
on	O
the	O
Apple	B-Device
II	I-Device
coprocessor	O
card	O
,	O
necessary	O
for	O
allowing	O
the	O
floppy	B-Device
drive	I-Device
motor	O
to	O
move	O
in	O
half-steps	O
among	O
tracks	O
,	O
a	O
feature	O
favored	O
by	O
certain	O
Apple	B-Device
II	I-Device
software	O
developers	O
to	O
copy-protect	B-Application
their	O
commercial	O
releases	O
.	O
</s>
<s>
Copy	B-Application
protection	I-Application
schemes	O
relying	O
on	O
specific	O
timings	O
of	O
the	O
Apple	B-Device
II	I-Device
's	O
disk	O
loader	O
routine	O
,	O
on	O
the	O
other	O
hand	O
,	O
may	O
cause	O
some	O
software	O
to	O
fail	O
to	O
load	O
,	O
because	O
of	O
the	O
Motorola	B-Device
68000	I-Device
's	O
handling	O
of	O
certain	O
interrupts	B-Application
during	O
this	O
routine	O
.	O
</s>
<s>
As	O
opposed	O
to	O
loading	O
IBM	O
emulation	O
mode	O
,	O
which	O
only	O
requires	O
the	O
user	O
enter	O
at	O
the	O
Dimension	B-Device
68000	I-Device
's	O
native	O
CP/M	B-Application
prompt	O
,	O
the	O
Dimension	B-Device
68000	I-Device
's	O
Apple	B-Device
II	I-Device
emulation	O
mode	O
requires	O
the	O
user	O
enter	O
several	O
arguments	O
after	O
.	O
</s>
<s>
The	O
Apple	B-Device
II	I-Device
emulation	O
mode	O
additionally	O
requires	O
the	O
user	O
provide	O
their	O
own	O
copy	O
of	O
an	O
operating	B-General_Concept
system	I-General_Concept
,	O
such	O
as	O
Apple	B-Operating_System
DOS	I-Operating_System
or	O
ProDOS	B-Operating_System
.	O
</s>
<s>
Once	O
booted	O
into	O
a	O
Applesoft	B-Language
BASIC	I-Language
prompt	O
,	O
however	O
,	O
the	O
interpreter	O
recognizes	O
all	O
BASIC	O
syntax	O
,	O
down	O
to	O
the	O
s	O
and	O
s	O
.	O
As	O
well	O
,	O
the	O
Apple	B-Device
II	I-Device
coprocessor	O
card	O
emulates	O
a	O
full	O
deck	O
of	O
Apple	B-Device
II	I-Device
peripheral	O
cards	O
:	O
in	O
slot	O
0	O
is	O
the	O
16KB	O
Language	O
Card	O
;	O
in	O
slot	O
1	O
is	O
the	O
parallel	O
card	O
;	O
in	O
slot	O
2	O
is	O
the	O
serial	O
card	O
;	O
in	O
slot	O
3	O
is	O
the	O
80-Column	B-Device
Text	I-Device
Card	I-Device
;	O
in	O
slot	O
6	O
is	O
the	O
floppy	B-Device
controller	O
,	O
with	O
two	O
virtual	O
Apple	O
disk	O
drives	O
plugged	O
in	O
;	O
and	O
in	O
slot	O
7	O
is	O
the	O
hard	O
drive	O
controller	O
card	O
.	O
</s>
<s>
Applesoft	B-Language
BASIC	I-Language
can	O
be	O
used	O
to	O
invoke	O
any	O
of	O
these	O
cards	O
with	O
expected	O
behavior	O
;	O
for	O
example	O
,	O
to	O
load	O
the	O
80-Column	B-Device
Text	I-Device
Card	I-Device
,	O
the	O
user	O
enters	O
at	O
the	O
prompt	O
.	O
</s>
<s>
The	O
IBM	B-Device
PC	I-Device
coprocessor	O
card	O
runs	O
off	O
an	O
Intel	B-General_Concept
8086	I-General_Concept
clocked	O
at	O
7.3MHz	O
,	O
slightly	O
less	O
than	O
twice	O
the	O
speed	O
of	O
the	O
IBM	B-Device
PC	I-Device
's	O
4.77-MHz	O
Intel	B-Device
8088	I-Device
(	O
a	O
variant	O
of	O
the	O
8086	B-General_Concept
with	O
an	O
eight-bit	O
external	O
data	O
bus	O
)	O
.	O
</s>
<s>
This	O
faster	O
clock	O
speed	O
was	O
chosen	O
to	O
compensate	O
for	O
any	O
slowdown	O
caused	O
by	O
software	O
emulation	O
and	O
interrupt	B-Application
handling	I-Application
by	O
the	O
Motorola	B-Device
68000	I-Device
.	O
</s>
<s>
The	O
resulting	O
speed	O
of	O
calculations	O
performed	O
within	O
spreadsheet	B-Application
software	I-Application
was	O
comparable	O
to	O
a	O
real	O
IBM	B-Device
PC	I-Device
's	O
speed	O
,	O
according	O
to	O
Popular	O
Computing	O
.	O
</s>
<s>
The	O
standard	O
emulation	O
program	O
on	O
the	O
IBM	O
"	O
emulation	O
master	O
"	O
disk	O
emulates	O
an	O
IBM	B-Device
PC	I-Device
with	O
a	O
CGA	B-Device
monitor	O
displaying	O
text	O
at	O
80	O
columns	O
by	O
25	O
rows	O
.	O
</s>
<s>
The	O
first	O
,	O
,	O
emulates	O
a	O
PC	O
with	O
a	O
CGA	B-Device
monitor	O
displaying	O
text	O
at	O
40	O
columns	O
by	O
25	O
rows	O
.	O
</s>
<s>
The	O
second	O
,	O
,	O
emulates	O
a	O
PC	O
with	O
a	O
Monochrome	B-Device
Display	I-Device
Adapter	I-Device
monitor	O
displaying	O
text	O
at	O
80	O
columns	O
by	O
25	O
rows	O
but	O
incapable	O
of	O
displaying	O
any	O
graphics	O
.	O
</s>
<s>
The	O
last	O
,	O
,	O
was	O
an	O
experimental	O
"	O
enhanced	O
"	O
IBM	O
emulation	O
mode	O
,	O
version	O
1.18	O
,	O
which	O
as	O
of	O
September	O
1984	O
had	O
not	O
been	O
fully	O
debugged	O
;	O
it	O
added	O
direct	O
I/O	O
to	O
the	O
NEC	O
765	O
and	O
expanded	O
the	O
capability	O
of	O
the	O
RS-232	O
serial	O
port	O
under	O
IBM	B-Device
PC	I-Device
emulation	O
.	O
</s>
<s>
In	O
this	O
way	O
,	O
the	O
emulation	O
programs	O
defaulted	O
to	O
running	O
the	O
maximum	O
amount	O
of	O
RAM	B-Architecture
possible	O
,	O
minus	O
some	O
reserved	O
for	O
the	O
emulation	O
software	O
.	O
</s>
<s>
Running	O
(	O
CGA	B-Device
,	O
80-by-25	O
text	O
)	O
on	O
a	O
machine	O
equipped	O
with	O
512KB	O
of	O
RAM	B-Architecture
,	O
for	O
example	O
,	O
left	O
412KB	O
addressable	O
to	O
the	O
virtual	O
machine	O
.	O
</s>
<s>
Some	O
arguments	O
could	O
be	O
passed	O
to	O
these	O
emulation	O
programs	O
:	O
limited	O
the	O
memory	O
to	O
a	O
set	O
amount	O
;	O
rendered	O
characters	O
with	O
the	O
intensity	O
bit	O
set	O
to	O
high	O
as	O
reverse	O
video	O
(	O
see	O
IBM	B-Device
Monochrome	I-Device
Display	I-Device
Adapter	I-Device
§	O
Capabilities	O
)	O
;	O
and	O
is	O
a	O
software	O
analogue	O
to	O
the	O
DIP	B-Algorithm
switches	O
on	O
an	O
IBM	B-Device
PC	I-Device
's	O
motherboard	O
,	O
used	O
to	O
set	O
certain	O
hardware	O
parameters	O
.	O
</s>
<s>
A	O
README	O
file	O
on	O
the	O
"	O
emulation	O
master	O
"	O
disk	O
of	O
the	O
IBM	B-Device
PC	I-Device
emulation	O
card	O
lists	O
known	O
bugs	O
.	O
</s>
<s>
In	O
September	O
1984	O
,	O
these	O
included	O
the	O
system	O
not	O
falling	O
back	O
on	O
IBM	O
Advanced	O
BASIC	O
on	O
the	O
lack	O
of	O
a	O
boot	O
disk	O
(	O
Micro	B-Device
Craft	I-Device
had	O
not	O
secured	O
the	O
rights	O
from	O
IBM	O
by	O
then	O
)	O
,	O
no	O
support	O
for	O
the	O
joystick	B-Device
port	O
,	O
no	O
direct	O
I/O	O
to	O
the	O
NEC	O
765	O
(	O
the	O
user	O
had	O
to	O
run	O
the	O
experimental	O
to	O
get	O
this	O
)	O
,	O
and	O
channel	O
2	O
of	O
the	O
PC	B-Device
speaker	I-Device
not	O
working	O
,	O
among	O
others	O
.	O
</s>
<s>
By	O
November	O
1984	O
,	O
the	O
card	O
still	O
had	O
no	O
support	O
for	O
channel	O
2	O
of	O
the	O
PC	B-Device
speaker	I-Device
,	O
and	O
it	O
became	O
known	O
that	O
interrupt	B-Application
calls	O
to	O
the	O
sound	O
generator	O
would	O
still	O
be	O
handled	O
as	O
no-ops	B-Language
,	O
leading	O
to	O
erratic	O
behavior	O
in	O
sound-capable	O
video	O
games	O
,	O
such	O
as	O
Microsoft	B-Operating_System
Flight	I-Operating_System
Simulator	I-Operating_System
.	O
</s>
<s>
Users	O
could	O
exit	O
IBM	B-Device
PC	I-Device
emulation	O
mode	O
by	O
invoking	O
Control-Alt-Delete	B-Device
or	O
by	O
pressing	O
the	O
reset	B-Application
button	I-Application
on	O
the	O
Dimension	B-Device
68000	I-Device
.	O
</s>
<s>
The	O
CP/M	B-Application
coprocessor	O
card	O
runs	O
off	O
a	O
4-MHz	O
Zilog	B-General_Concept
Z80A	I-General_Concept
.	O
</s>
<s>
Unlike	O
with	O
the	O
Apple	B-Device
II	I-Device
and	O
IBM	B-Device
PC	I-Device
emulation	O
modes	O
,	O
delivery	O
of	O
the	O
Z80	B-General_Concept
card	O
came	O
with	O
a	O
version	O
of	O
CP/M	B-Application
2.2	O
for	O
the	O
Z80	B-General_Concept
,	O
complete	O
with	O
the	O
manual	O
from	O
Digital	O
Research	O
.	O
</s>
<s>
The	O
four	O
emulator	O
programs	O
on	O
the	O
"	O
emulation	O
master	O
"	O
disk	O
included	O
with	O
the	O
CP/M	B-Application
card	O
only	O
support	O
addressing	O
up	O
to	O
64KB	O
of	O
RAM	B-Architecture
,	O
two	O
dual-sided	O
,	O
40-track	O
,	O
5.25-inch	O
floppy	B-Device
disk	I-Device
drives	I-Device
,	O
the	O
parallel	O
port	O
interface	O
(	O
for	O
printers	O
)	O
,	O
and	O
the	O
ADM-3	B-Device
display	O
terminal	O
and	O
its	O
clones	O
.	O
</s>
<s>
The	O
systems	O
these	O
emulators	O
aim	O
to	O
reproduce	O
are	O
the	O
Kaypro	O
II	O
(	O
)	O
,	O
the	O
Osborne	B-Device
1	I-Device
(	O
)	O
,	O
and	O
S-100-based	O
Cromemco	O
computers	O
(	O
)	O
.	O
</s>
<s>
The	O
fourth	O
emulator	O
,	O
,	O
aims	O
to	O
emulate	O
an	O
archetypal	O
Z80-based	O
CP/M	B-Operating_System
machine	I-Operating_System
.	O
</s>
<s>
is	O
the	O
only	O
emulator	O
to	O
support	O
drive	O
letters	O
past	O
,	O
including	O
through	O
(	O
skipping	O
however	O
)	O
,	O
with	O
being	O
a	O
RAM	B-Application
drive	I-Application
.	O
</s>
<s>
The	O
native	O
operating	B-General_Concept
system	I-General_Concept
of	O
the	O
Dimension	B-Device
68000	I-Device
,	O
as	O
included	O
in	O
the	O
system	O
disk	O
,	O
is	O
CP/M	B-Application
68K	O
,	O
a	O
port	O
of	O
CP/M	B-Application
for	O
the	O
Motorola	B-Device
68000	I-Device
,	O
developed	O
by	O
Digital	O
Research	O
in	O
the	O
days	O
before	O
the	O
Z80	B-General_Concept
came	O
to	O
be	O
recognized	O
as	O
CP/M	B-Application
'	O
s	O
de	O
facto	O
standard	O
platform	O
.	O
</s>
<s>
Mirage	O
,	O
a	O
little	O
known	O
operating	B-General_Concept
system	I-General_Concept
native	O
to	O
the	O
Motorola	B-Device
68000	I-Device
,	O
and	O
SofTech	B-Language
Pascal	I-Language
were	O
offered	O
as	O
multi-user	B-Operating_System
counterpoints	O
to	O
the	O
single-user	B-Operating_System
CP/M	B-Application
,	O
which	O
was	O
seen	O
by	O
contemporary	O
computer	O
journalists	O
as	O
limiting	O
the	O
Motorola	B-Device
68000	I-Device
's	O
full	O
potential	O
.	O
</s>
<s>
Micro	B-Device
Craft	I-Device
promised	O
a	O
port	O
of	O
Unix	B-Operating_System
first	O
in	O
1983	O
,	O
then	O
in	O
1984	O
,	O
and	O
again	O
in	O
mid-1985	O
.	O
</s>
<s>
Micro	B-Device
Craft	I-Device
finally	O
delivered	O
a	O
four-user	O
version	O
of	O
Unix	B-Operating_System
for	O
the	O
Dimension	B-Device
68000	I-Device
in	O
October	O
1985	O
.	O
</s>
<s>
The	O
version	O
of	O
CP/M	B-Application
68K	O
included	O
with	O
the	O
Dimension	B-Device
68000	I-Device
includes	O
the	O
file-transfer	O
utility	O
PIP	B-Application
,	O
the	O
debugger	O
DDT-68K	B-Operating_System
,	O
the	O
file	O
system	O
statistic	O
utility	O
,	O
a	O
Motorola	B-Device
68000	I-Device
C	B-Language
compiler	B-Language
,	O
a	O
linking	B-Application
loader	I-Application
,	O
and	O
a	O
68000	B-Device
assembler	B-Application
.	O
</s>
<s>
Unibasic	O
,	O
a	O
BASIC	O
dialect	O
developed	O
specifically	O
for	O
the	O
Dimension	B-Device
68000	I-Device
by	O
Dallas-based	O
RD	O
Software	O
,	O
was	O
also	O
included	O
in	O
the	O
package	O
.	O
</s>
<s>
Although	O
native	O
to	O
the	O
Motorola	B-Device
68000	I-Device
,	O
with	O
all	O
16MB	O
of	O
the	O
Motorola	B-Device
68000	I-Device
's	O
address	O
space	O
supported	O
by	O
it	O
,	O
Unibasic	O
was	O
very	O
closely	O
based	O
on	O
Applesoft	B-Language
BASIC	I-Language
.	O
</s>
<s>
For	O
example	O
,	O
Unibasic	O
's	O
s	O
and	O
s	O
for	O
manipulation	O
of	O
printers	O
,	O
video	O
display	O
,	O
and	O
keyboard	O
input	O
expect	O
memory	O
addresses	O
identical	O
those	O
used	O
by	O
Applesoft	O
for	O
such	O
devices	O
(	O
meanwhile	O
and	O
could	O
be	O
used	O
to	O
read	O
and	O
manipulate	O
the	O
absolute	O
memory	O
addresses	O
of	O
the	O
Motorola	B-Device
6800	I-Device
)	O
.	O
</s>
<s>
At	O
least	O
one	O
third-party	O
software	O
developer	O
released	O
a	O
software	O
package	O
specifically	O
for	O
the	O
Dimension	B-Device
68000	I-Device
.	O
</s>
<s>
The	O
Dimension	B-Device
68000	I-Device
is	O
primarily	O
the	O
brainchild	O
of	O
Mike	O
Carpenter	O
,	O
the	O
former	O
president	O
of	O
Scientific	O
Machines	O
,	O
a	O
company	O
that	O
manufactured	O
scientific	O
instruments	O
.	O
</s>
<s>
Development	O
of	O
the	O
computer	O
commenced	O
on	O
Micro	B-Device
Craft	I-Device
Corporation	I-Device
's	O
incorporation	O
in	O
Dallas	O
,	O
Texas	O
,	O
in	O
November	O
1981	O
.	O
</s>
<s>
He	O
set	O
out	O
the	O
Dimension	B-Device
68000	I-Device
to	O
be	O
the	O
epitome	O
of	O
a	O
"	O
compatible	B-Device
"	O
computer	O
system	O
—	O
interoperable	O
between	O
all	O
the	O
popular	O
computing	O
platforms	O
,	O
providing	O
a	O
powerful	O
microprocessor	O
,	O
and	O
following	O
design	O
philosophies	O
to	O
make	O
the	O
computer	O
as	O
resistant	O
to	O
obsolescence	O
as	O
possible	O
.	O
</s>
<s>
Carpenter	O
employed	O
the	O
help	O
of	O
several	O
employees	O
from	O
companies	O
for	O
which	O
the	O
Dimension	B-Device
68000	I-Device
emulates	O
,	O
including	O
IBM	O
and	O
Apple	O
.	O
</s>
<s>
The	O
first	O
shipment	O
of	O
Dimension	B-Device
68000	I-Device
commenced	O
in	O
October	O
1983	O
.	O
</s>
<s>
A	O
network	O
of	O
80	O
to	O
90	O
dealers	O
was	O
established	O
the	O
previous	O
month	O
to	O
distribute	O
250	O
Dimension	B-Device
68000s	I-Device
across	O
the	O
United	O
States	O
.	O
</s>
<s>
Another	O
round	O
of	O
shipments	O
occurred	O
in	O
April	O
1984	O
,	O
by	O
which	O
point	O
Micro	B-Device
Craft	I-Device
had	O
culled	O
some	O
of	O
their	O
dealers	O
,	O
leaving	O
77	O
in	O
their	O
network	O
.	O
</s>
<s>
Micro	B-Device
Craft	I-Device
filed	O
for	O
Chapter	O
11	O
bankruptcy	O
in	O
early	O
1985	O
.	O
</s>
<s>
They	O
were	O
guided	O
out	O
by	O
businessman	O
Donald	O
F	O
.	O
Bynum	O
in	O
less	O
than	O
three	O
months	O
and	O
continued	O
selling	O
the	O
Dimension	B-Device
68000	I-Device
for	O
the	O
next	O
year	O
.	O
</s>
<s>
Although	O
an	O
early	O
1986	O
newspaper	O
article	O
noted	O
that	O
the	O
Dimension	B-Device
68000	I-Device
"	O
never	O
hit	O
it	O
big	O
"	O
,	O
Micro	B-Device
Craft	I-Device
and	O
their	O
intellectual	O
property	O
were	O
bought	O
by	O
an	O
Arkansas-based	O
holding	O
company	O
shortly	O
thereafter	O
.	O
</s>
<s>
The	O
company	O
was	O
rechristened	O
as	O
Dimension	O
Electronics	O
in	O
1987	O
,	O
releasing	O
a	O
redesigned	O
version	O
of	O
the	O
Dimension	B-Device
68000	I-Device
,	O
the	O
New	O
Dimension	B-Device
68000	I-Device
,	O
that	O
year	O
.	O
</s>
<s>
This	O
incarnation	O
of	O
the	O
Dimension	B-Device
68000	I-Device
offered	O
a	O
new	O
Macintosh	B-Device
emulation	O
mode	O
.	O
</s>
<s>
InfoWorld	O
in	O
1989	O
described	O
the	O
overall	O
lifespan	O
of	O
the	O
Dimension	B-Device
68000	I-Device
as	O
short-lived	O
.	O
</s>
<s>
Advertisements	O
of	O
the	O
Dimension	B-Device
68000	I-Device
in	O
computer	O
magazines	O
generated	O
massive	O
hype	O
for	O
Micro	B-Device
Craft	I-Device
,	O
the	O
company	O
receiving	O
over	O
50,000	O
queries	O
by	O
April	O
1984	O
,	O
according	O
to	O
Barbara	O
Henry-Arnold	O
,	O
Micro	B-Device
Craft	I-Device
's	O
director	O
of	O
communications	O
.	O
</s>
<s>
By	O
the	O
middle	O
of	O
1985	O
,	O
however	O
,	O
Micro	B-Device
Craft	I-Device
was	O
downplaying	O
its	O
role	O
as	O
an	O
polymathic	O
tool	O
in	O
favor	O
of	O
the	O
potential	O
for	O
its	O
Motorola	B-Device
68000	I-Device
to	O
cooperate	O
with	O
the	O
coprocessors	O
in	O
the	O
computer	O
's	O
native	O
mode	O
.	O
</s>
<s>
Reviewing	O
a	O
pre-production	O
unit	O
,	O
although	O
he	O
encountered	O
some	O
problems	O
in	O
IBM	B-Device
PC	I-Device
emulation	O
mode	O
,	O
Jim	O
Heid	O
of	O
Microcomputing	B-Architecture
called	O
the	O
Dimension	O
's	O
emulation	O
powers	O
"	O
amazing	O
"	O
in	O
its	O
breadth	O
.	O
</s>
<s>
Rimmer	O
however	O
called	O
the	O
machine	O
unrealistic	O
for	O
prospective	O
buyers	O
who	O
wanted	O
a	O
"	O
clone	O
replacer	O
"	O
,	O
feeling	O
that	O
they	O
would	O
be	O
better	O
suited	O
buying	O
authentically	O
compatible	B-Device
systems	O
,	O
the	O
combined	O
cost	O
of	O
which	O
would	O
be	O
less	O
than	O
the	O
Dimension	B-Device
68000	I-Device
's	O
.	O
</s>
<s>
Bright	O
criticized	O
the	O
use	O
of	O
CP/M	B-Operating_System
-86	I-Operating_System
as	O
a	O
single-user	B-Operating_System
operating	B-General_Concept
system	I-General_Concept
but	O
saw	O
potential	O
if	O
more	O
popular	O
multi-user	B-Operating_System
OSes	O
such	O
as	O
Unix	B-Operating_System
came	O
to	O
support	O
the	O
Dimension	B-Device
68000	I-Device
and	O
wrote	O
that	O
the	O
range	O
of	O
its	O
emulation	O
was	O
unparalleled	O
.	O
</s>
<s>
Popular	O
Computing	O
Rick	O
Cook	O
wrote	O
that	O
,	O
counter	O
to	O
the	O
interest	O
of	O
prospective	O
buyers	O
who	O
had	O
been	O
wooed	O
by	O
advertisements	O
in	O
computer	O
magazines	O
,	O
most	O
would	O
be	O
disappointed	O
:	O
"	O
The	O
Dimension	B-Device
68000	I-Device
is	O
powerful	O
,	O
but	O
it	O
cannot	O
do	O
everything.	O
"	O
</s>
<s>
Cook	O
deemed	O
the	O
computer	O
's	O
native	O
number-crunching	O
performance	O
good	O
and	O
found	O
it	O
one	O
of	O
the	O
cheaper	O
68000-based	O
microcomputers	B-Architecture
on	O
the	O
market	O
,	O
albeit	O
at	O
a	O
price	O
not	O
factoring	O
in	O
a	O
hard	O
drive	O
,	O
which	O
was	O
seen	O
as	O
an	O
increasingly	O
important	O
device	O
for	O
such	O
micros	O
.	O
</s>
<s>
He	O
saw	O
the	O
coprocessor	O
arrangement	O
useful	O
in	O
applications	O
besides	O
emulation	O
,	O
such	O
as	O
in	O
Unix-like	O
operating	B-General_Concept
systems	I-General_Concept
that	O
could	O
take	O
advantage	O
of	O
more	O
than	O
one	O
processor	O
.	O
</s>
<s>
But	O
at	O
"	O
the	O
$5500	O
cost	O
of	O
the	O
Dimension	O
emulation	O
package	O
,	O
"	O
Cook	O
wrote	O
,	O
"	O
you	O
are	O
close	O
to	O
getting	O
an	O
IBM	B-Device
PC	I-Device
or	O
PC	O
clone	O
,	O
an	O
Apple	B-Device
II	I-Device
,	O
and	O
a	O
low-priced	O
CP/M	B-Application
system	O
,	O
such	O
as	O
the	O
Kaypro	O
II.	O
"	O
</s>
<s>
Stephen	O
T	O
.	O
Satchell	O
of	O
InfoWorld	O
,	O
on	O
the	O
other	O
hand	O
,	O
found	O
it	O
slow	O
in	O
native	O
mode	O
—	O
somewhere	O
between	O
the	O
8086	B-General_Concept
Compaq	B-Device
Deskpro	I-Device
and	O
the	O
original	O
IBM	B-Device
PC	I-Device
in	O
terms	O
performance	O
per	O
a	O
benchmark	O
—	O
but	O
called	O
the	O
speed	O
of	O
its	O
IBM	B-Device
PC	I-Device
emulation	O
adequate	O
,	O
although	O
the	O
emulator	O
did	O
not	O
run	O
perfectly	O
for	O
him	O
in	O
some	O
applications	O
,	O
such	O
as	O
Microsoft	B-Operating_System
Flight	I-Operating_System
Simulator	I-Operating_System
and	O
Microsoft	B-Application
Adventure	I-Application
.	O
</s>
<s>
He	O
concluded	O
by	O
stating	O
that	O
if	O
Micro	B-Device
Craft	I-Device
"	O
would	O
spend	O
less	O
time	O
on	O
the	O
frill	O
of	O
emulation	O
and	O
more	O
on	O
the	O
basic	O
processing	O
system	O
,	O
it	O
would	O
have	O
a	O
dynamite	O
product.	O
"	O
</s>
<s>
Native	O
mode	O
Fortran	O
and	O
Pascal	O
on	O
the	O
Dimension	O
run	O
rings	O
around	O
the	O
IBM	B-Device
PC	I-Device
AT.	O
"	O
</s>
