<s>
The	O
Apple	B-Device
II	I-Device
(	O
stylized	O
as	O
)	O
is	O
an	O
8-bit	O
home	O
computer	O
and	O
one	O
of	O
the	O
world	O
's	O
first	O
highly	O
successful	O
mass-produced	O
microcomputer	B-Architecture
products	O
.	O
</s>
<s>
It	O
was	O
designed	O
primarily	O
by	O
Steve	O
Wozniak	O
;	O
Jerry	O
Manock	O
developed	O
the	O
design	O
of	O
Apple	B-Device
II	I-Device
's	O
foam-molded	O
plastic	O
case	O
,	O
Rod	O
Holt	O
developed	O
the	O
switching	O
power	O
supply	O
,	O
while	O
Steve	O
Jobs	O
's	O
role	O
in	O
the	O
design	O
of	O
the	O
computer	O
was	O
limited	O
to	O
overseeing	O
Jerry	O
Manock	O
's	O
work	O
on	O
the	O
plastic	O
case	O
.	O
</s>
<s>
Byte	O
magazine	O
referred	O
to	O
the	O
Apple	B-Device
II	I-Device
,	O
Commodore	B-Device
PET	I-Device
2001	I-Device
,	O
and	O
TRS-80	B-Device
as	O
the	O
"	O
1977	O
Trinity	O
"	O
.	O
</s>
<s>
As	O
the	O
Apple	B-Device
II	I-Device
had	O
the	O
defining	O
feature	O
of	O
being	O
able	O
to	O
display	O
color	B-Device
graphics	I-Device
,	O
the	O
Apple	O
logo	O
was	O
redesigned	O
to	O
have	O
a	O
spectrum	O
of	O
colors	O
.	O
</s>
<s>
The	O
Apple	B-Device
II	I-Device
is	O
the	O
first	O
model	O
in	O
the	O
Apple	B-Device
II	I-Device
series	I-Device
,	O
followed	O
by	O
Apple	O
II+	O
,	O
Apple	B-Device
IIe	I-Device
,	O
Apple	O
IIc	O
,	O
Apple	B-Device
IIc	I-Device
Plus	I-Device
,	O
and	O
the	O
16-bit	O
Apple	B-Device
IIGS	I-Device
—	O
all	O
of	O
which	O
remained	O
compatible	O
.	O
</s>
<s>
Production	O
of	O
the	O
last	O
available	O
model	O
,	O
Apple	B-Device
IIe	I-Device
,	O
ceased	O
in	O
November	O
1993	O
.	O
</s>
<s>
By	O
1976	O
,	O
Steve	O
Jobs	O
had	O
convinced	O
product	O
designer	O
Jerry	O
Manock	O
(	O
who	O
had	O
formerly	O
worked	O
at	O
Hewlett	O
Packard	O
designing	O
calculators	O
)	O
to	O
create	O
the	O
"	O
shell	O
"	O
for	O
the	O
Apple	B-Device
II	I-Device
—	O
a	O
smooth	O
case	O
inspired	O
by	O
kitchen	O
appliances	O
that	O
concealed	O
the	O
internal	O
mechanics	O
.	O
</s>
<s>
The	O
earliest	O
Apple	B-Device
II	I-Device
computers	I-Device
were	O
assembled	O
in	O
Silicon	O
Valley	O
and	O
later	O
in	O
Texas	O
;	O
printed	O
circuit	O
boards	O
were	O
manufactured	O
in	O
Ireland	O
and	O
Singapore	O
.	O
</s>
<s>
The	O
first	O
computers	O
went	O
on	O
sale	O
on	O
June	O
10	O
,	O
1977	O
with	O
an	O
MOS	B-General_Concept
Technology	I-General_Concept
6502	I-General_Concept
microprocessor	O
running	O
at	O
1.022	O
MHz	O
(	O
of	O
the	O
NTSC	O
color	O
carrier	O
)	O
,	O
two	O
game	B-Device
paddles	I-Device
(	O
bundled	O
until	O
1980	O
,	O
when	O
they	O
were	O
found	O
to	O
violate	O
FCC	O
regulations	O
)	O
,	O
4	O
KiB	O
of	O
RAM	B-Architecture
,	O
an	O
audio	B-Device
cassette	I-Device
interface	O
for	O
loading	O
programs	O
and	O
storing	O
data	O
,	O
and	O
the	O
Integer	B-Language
BASIC	I-Language
programming	I-Language
language	I-Language
built	O
into	O
ROMs	B-Device
.	O
</s>
<s>
The	O
original	O
retail	O
price	O
of	O
the	O
computer	O
with	O
4	O
KiB	O
of	O
RAM	B-Architecture
was	O
and	O
with	O
the	O
maximum	O
48KB	O
of	O
RAM	B-Architecture
.	O
</s>
<s>
To	O
reflect	O
the	O
computer	O
's	O
color	B-Device
graphics	I-Device
capability	O
,	O
the	O
Apple	O
logo	O
on	O
the	O
casing	O
had	O
rainbow	O
stripes	O
,	O
which	O
remained	O
a	O
part	O
of	O
Apple	O
's	O
corporate	O
logo	O
until	O
early	O
1998	O
.	O
</s>
<s>
Perhaps	O
most	O
significantly	O
,	O
the	O
Apple	B-Device
II	I-Device
was	O
a	O
catalyst	O
for	O
personal	O
computers	O
across	O
many	O
industries	O
;	O
it	O
opened	O
the	O
doors	O
to	O
software	O
marketed	O
at	O
consumers	O
.	O
</s>
<s>
Certain	O
aspects	O
of	O
the	O
system	O
's	O
design	O
were	O
influenced	O
by	O
Atari	O
's	O
arcade	B-Application
video	I-Application
game	I-Application
Breakout	B-Application
(	O
1976	O
)	O
,	O
which	O
was	O
designed	O
by	O
Wozniak	O
,	O
who	O
said	O
:	O
"	O
A	O
lot	O
of	O
features	O
of	O
the	O
Apple	B-Device
II	I-Device
went	O
in	O
because	O
I	O
had	O
designed	O
Breakout	B-Application
for	O
Atari	O
.	O
</s>
<s>
This	O
included	O
his	O
design	O
of	O
color	B-Device
graphics	I-Device
circuitry	O
,	O
the	O
addition	O
of	O
game	B-Device
paddle	I-Device
support	O
and	O
sound	O
,	O
and	O
graphics	O
commands	O
in	O
Integer	B-Language
BASIC	I-Language
,	O
with	O
which	O
he	O
wrote	O
Brick	O
Out	O
,	O
a	O
software	O
clone	O
of	O
his	O
own	O
hardware	O
game	O
.	O
</s>
<s>
Wozniak	O
said	O
in	O
1984	O
:	O
"	O
Basically	O
,	O
all	O
the	O
game	O
features	O
were	O
put	O
in	O
just	O
so	O
I	O
could	O
show	O
off	O
the	O
game	O
I	O
was	O
familiar	O
with	O
—	O
Breakout	B-Application
—	O
at	O
the	O
Homebrew	O
Computer	O
Club	O
.	O
</s>
<s>
The	O
Apple	B-Device
II	I-Device
used	O
peculiar	O
engineering	O
shortcuts	O
to	O
save	O
hardware	O
and	O
reduce	O
costs	O
,	O
such	O
as	O
:	O
</s>
<s>
Taking	O
advantage	O
of	O
the	O
way	O
the	O
6502	B-General_Concept
processor	I-General_Concept
accesses	O
memory	O
:	O
it	O
occurs	O
only	O
on	O
alternate	O
phases	O
of	O
the	O
clock	O
cycle	O
;	O
video	O
generation	O
circuitry	O
memory	O
access	O
on	O
the	O
otherwise	O
unused	O
phase	O
avoids	O
memory	O
contention	O
issues	O
and	O
interruptions	O
of	O
the	O
video	O
stream	O
.	O
</s>
<s>
This	O
arrangement	O
simultaneously	O
eliminated	O
the	O
need	O
for	O
a	O
separate	O
refresh	B-General_Concept
circuit	O
for	O
DRAM	O
chips	O
,	O
as	O
video	O
transfer	O
accessed	O
each	O
row	O
of	O
dynamic	O
memory	O
within	O
the	O
timeout	O
period	O
.	O
</s>
<s>
In	O
addition	O
,	O
it	O
did	O
not	O
require	O
separate	O
RAM	B-Architecture
chips	I-Architecture
for	O
video	O
RAM	B-Architecture
,	O
while	O
the	O
PET	O
and	O
TRS-80	B-Device
had	O
SRAM	O
chips	O
for	O
video	O
.	O
</s>
<s>
This	O
complexity	O
was	O
reportedly	O
due	O
to	O
Wozniak	O
's	O
realization	O
that	O
the	O
method	O
would	O
allow	O
for	O
the	O
refresh	B-General_Concept
of	O
dynamic	O
RAM	B-Architecture
as	O
a	O
side	O
effect	O
(	O
as	O
described	O
above	O
)	O
.	O
</s>
<s>
Similarly	O
,	O
in	O
high-resolution	O
graphics	O
mode	O
,	O
color	O
is	O
determined	O
by	O
pixel	B-Algorithm
position	O
and	O
thus	O
can	O
be	O
implemented	O
in	O
software	O
,	O
saving	O
Wozniak	O
the	O
chips	O
needed	O
to	O
convert	O
bit	O
patterns	O
to	O
colors	O
.	O
</s>
<s>
This	O
also	O
allowed	O
for	O
subpixel	O
font	O
rendering	O
,	O
since	O
orange	O
and	O
blue	O
pixels	B-Algorithm
appear	O
half	O
a	O
pixel-width	O
farther	O
to	O
the	O
right	O
on	O
the	O
screen	O
than	O
green	O
and	O
purple	O
pixels	B-Algorithm
.	O
</s>
<s>
The	O
Apple	B-Device
II	I-Device
at	O
first	O
used	O
data	O
cassette	O
storage	O
,	O
like	O
most	O
other	O
microcomputers	B-Architecture
of	O
the	O
time	O
.	O
</s>
<s>
The	O
Disk	B-Device
II	I-Device
interface	O
,	O
created	O
by	O
Wozniak	O
,	O
is	O
regarded	O
as	O
an	O
engineering	O
masterpiece	O
for	O
its	O
economy	O
of	O
electronic	O
components	O
.	O
</s>
<s>
The	O
approach	O
taken	O
in	O
the	O
Disk	B-Device
II	I-Device
controller	O
is	O
typical	O
of	O
Wozniak	O
's	O
designs	O
.	O
</s>
<s>
With	O
a	O
few	O
small-scale	O
logic	O
chips	O
and	O
a	O
cheap	O
PROM	O
(	O
programmable	B-General_Concept
read-only	I-General_Concept
memory	I-General_Concept
)	O
,	O
he	O
created	O
a	O
functional	O
floppy	B-Device
disk	I-Device
interface	O
at	O
a	O
fraction	O
of	O
the	O
component	O
cost	O
of	O
standard	O
circuit	O
configurations	O
.	O
</s>
<s>
The	O
first	O
production	O
Apple	B-Device
II	I-Device
computers	I-Device
had	O
hand-molded	O
cases	O
;	O
these	O
had	O
visible	O
bubbles	O
and	O
other	O
lumps	O
in	O
them	O
from	O
the	O
imperfect	O
plastic	O
molding	O
process	O
,	O
which	O
was	O
soon	O
switched	O
to	O
machine	O
molding	O
.	O
</s>
<s>
The	O
Apple	B-Device
II	I-Device
's	O
printed	O
circuit	O
board	O
(	O
PCB	O
)	O
underwent	O
several	O
revisions	O
,	O
as	O
Steve	O
Wozniak	O
made	O
modifications	O
to	O
it	O
.	O
</s>
<s>
Later	O
revisions	O
added	O
a	O
color	O
killer	O
circuit	O
to	O
prevent	O
color	O
fringing	O
when	O
the	O
computer	O
was	O
in	O
text	O
mode	O
,	O
as	O
well	O
as	O
modifications	O
to	O
improve	O
the	O
reliability	O
of	O
cassette	O
I/O	B-General_Concept
.	O
</s>
<s>
Revision	O
0	O
Apple	B-Device
IIs	I-Device
powered	O
up	O
in	O
an	O
undefined	O
mode	O
and	O
had	O
garbage	O
on-screen	O
,	O
requiring	O
the	O
user	O
to	O
press	O
Reset	O
.	O
</s>
<s>
Revision	O
0	O
Apple	B-Device
IIs	I-Device
could	O
display	O
only	O
four	O
colors	O
in	O
hi-res	O
mode	O
,	O
but	O
Wozniak	O
was	O
able	O
to	O
increase	O
this	O
to	O
six	O
hi-res	O
colors	O
on	O
later	O
board	O
revisions	O
.	O
</s>
<s>
The	O
PCB	O
had	O
three	O
RAM	B-Architecture
banks	O
for	O
a	O
total	O
of	O
24	O
RAM	B-Architecture
chips	I-Architecture
.	O
</s>
<s>
Original	O
Apple	B-Device
IIs	I-Device
had	O
jumper	O
switches	O
to	O
adjust	O
RAM	B-Architecture
size	O
,	O
and	O
RAM	B-Architecture
configurations	O
could	O
be	O
4	O
,	O
8	O
,	O
12	O
,	O
16	O
,	O
20	O
,	O
24	O
,	O
32	O
,	O
36	O
,	O
or	O
48KiB	O
.	O
</s>
<s>
Unlike	O
most	O
machines	O
,	O
all	O
integrated	O
circuits	O
on	O
the	O
Apple	B-Device
II	I-Device
PCB	O
were	O
socketed	O
;	O
although	O
this	O
cost	O
more	O
to	O
manufacture	O
and	O
created	O
the	O
possibility	O
of	O
loose	O
chips	O
causing	O
a	O
system	O
malfunction	O
,	O
it	O
was	O
considered	O
preferable	O
to	O
make	O
servicing	O
and	O
replacement	O
of	O
bad	O
chips	O
easier	O
.	O
</s>
<s>
The	O
Apple	B-Device
II	I-Device
PCB	O
lacks	O
any	O
means	O
of	O
generating	O
an	O
interrupt	B-General_Concept
request	I-General_Concept
,	O
although	O
expansion	B-Device
cards	I-Device
may	O
generate	O
one	O
.	O
</s>
<s>
Program	O
code	O
had	O
to	O
stop	O
everything	O
to	O
perform	O
any	O
I/O	B-General_Concept
task	O
;	O
like	O
many	O
of	O
the	O
computer	O
's	O
other	O
idiosyncrasies	O
,	O
this	O
was	O
due	O
to	O
cost	O
reasons	O
and	O
Steve	O
Wozniak	O
assuming	O
interrupts	O
were	O
not	O
needed	O
for	O
gaming	O
or	O
using	O
the	O
computer	O
as	O
a	O
teaching	O
tool	O
.	O
</s>
<s>
Color	O
on	O
the	O
Apple	B-Device
II	I-Device
series	I-Device
uses	O
a	O
quirk	O
of	O
the	O
NTSC	O
television	O
signal	O
standard	O
,	O
which	O
made	O
color	O
display	O
relatively	O
easy	O
and	O
inexpensive	O
to	O
implement	O
.	O
</s>
<s>
These	O
pulses	O
can	O
translate	O
into	O
pixels	B-Algorithm
on	O
the	O
computer	O
screen	O
,	O
with	O
the	O
possibility	O
of	O
exploiting	O
composite	O
artifact	O
colors	O
.	O
</s>
<s>
The	O
Apple	B-Device
II	I-Device
display	O
provides	O
two	O
pixels	B-Algorithm
per	O
subcarrier	O
cycle	O
.	O
</s>
<s>
When	O
the	O
color	O
burst	O
reference	O
signal	O
is	O
turned	O
on	O
and	O
the	O
computer	O
attached	O
to	O
a	O
color	O
display	O
,	O
it	O
can	O
display	O
green	O
by	O
showing	O
one	O
alternating	O
pattern	O
of	O
pixels	B-Algorithm
,	O
magenta	O
with	O
an	O
opposite	O
pattern	O
of	O
alternating	O
pixels	B-Algorithm
,	O
and	O
white	O
by	O
placing	O
two	O
pixels	B-Algorithm
next	O
to	O
each	O
other	O
.	O
</s>
<s>
Blue	O
and	O
orange	O
are	O
available	O
by	O
tweaking	O
the	O
pixel	B-Algorithm
offset	O
by	O
half	O
a	O
pixel-width	O
in	O
relation	O
to	O
the	O
color-burst	O
signal	O
.	O
</s>
<s>
The	O
high-resolution	O
display	O
offers	O
more	O
colors	O
by	O
compressing	O
more	O
(	O
and	O
narrower	O
)	O
pixels	B-Algorithm
into	O
each	O
subcarrier	O
cycle	O
.	O
</s>
<s>
The	O
coarse	O
,	O
low-resolution	O
graphics	O
display	O
mode	O
works	O
differently	O
,	O
as	O
it	O
can	O
output	O
a	O
pattern	O
of	O
dots	O
per	O
pixel	B-Algorithm
to	O
offer	O
more	O
color	O
options	O
.	O
</s>
<s>
These	O
patterns	O
are	O
stored	O
in	O
the	O
character	O
generator	O
ROM	B-Device
,	O
and	O
replace	O
the	O
text	O
character	O
bit	O
patterns	O
when	O
the	O
computer	O
is	O
switched	O
to	O
low-res	O
graphics	O
mode	O
.	O
</s>
<s>
A	O
single	O
HGR	O
page	O
occupied	O
8KiB	O
of	O
RAM	B-Architecture
;	O
in	O
practice	O
this	O
meant	O
that	O
the	O
user	O
had	O
to	O
have	O
at	O
least	O
12KiB	O
of	O
total	O
RAM	B-Architecture
to	O
use	O
HGR	O
mode	O
and	O
20KiB	O
to	O
use	O
two	O
pages	O
.	O
</s>
<s>
Early	O
Apple	B-Device
II	I-Device
games	O
from	O
the	O
1977	O
–	O
79	O
period	O
often	O
ran	O
only	O
in	O
text	O
or	O
low-resolution	O
mode	O
in	O
order	O
to	O
support	O
users	O
with	O
small	O
memory	O
configurations	O
;	O
HGR	O
not	O
being	O
near	O
universally	O
supported	O
by	O
games	O
until	O
1980	O
.	O
</s>
<s>
Rather	O
than	O
a	O
dedicated	O
sound-synthesis	O
chip	O
,	O
the	O
Apple	B-Device
II	I-Device
has	O
a	O
toggle	O
circuit	O
that	O
can	O
only	O
emit	O
a	O
click	O
through	O
a	O
built-in	O
speaker	O
or	O
a	O
line-out	O
jack	O
;	O
all	O
other	O
sounds	O
(	O
including	O
two-	O
,	O
three	O
-	O
and	O
,	O
eventually	O
,	O
four-voice	O
music	O
and	O
playback	O
of	O
audio	O
samples	O
and	O
speech	O
synthesis	O
)	O
are	O
generated	O
entirely	O
by	O
software	O
that	O
clicked	O
the	O
speaker	O
at	O
just	O
the	O
right	O
times	O
.	O
</s>
<s>
Routines	O
in	O
machine	O
ROM	B-Device
encode	O
and	O
decode	O
data	O
in	O
frequency-shift	O
keying	O
for	O
the	O
cassette	O
.	O
</s>
<s>
Initially	O
,	O
the	O
Apple	B-Device
II	I-Device
was	O
shipped	O
with	O
Integer	B-Language
BASIC	I-Language
encoded	O
in	O
the	O
motherboard	O
ROM	B-Device
chips	I-Device
.	O
</s>
<s>
Because	O
Steve	O
Wozniak	O
was	O
busy	O
developing	O
the	O
Disk	B-Device
II	I-Device
hardware	O
,	O
he	O
did	O
not	O
have	O
time	O
to	O
modify	O
Integer	B-Language
BASIC	I-Language
for	O
floating	O
point	O
support	O
.	O
</s>
<s>
Apple	O
instead	O
licensed	O
Microsoft	O
's	O
6502	B-General_Concept
BASIC	O
to	O
create	O
Applesoft	B-Language
BASIC	I-Language
.	O
</s>
<s>
Disk	O
users	O
normally	O
purchased	O
a	O
so-called	O
Language	O
Card	O
,	O
which	O
had	O
Applesoft	O
in	O
ROM	B-Device
,	O
and	O
was	O
sat	O
below	O
the	O
Integer	B-Language
BASIC	I-Language
ROM	B-Device
in	O
system	O
memory	O
.	O
</s>
<s>
Apple	O
also	O
offered	O
a	O
different	O
version	O
of	O
Applesoft	O
for	O
cassette	O
users	O
,	O
which	O
occupied	O
low	O
memory	O
,	O
and	O
was	O
started	O
by	O
using	O
the	O
LOAD	O
command	O
in	O
Integer	B-Language
BASIC	I-Language
.	O
</s>
<s>
As	O
shipped	O
,	O
Apple	B-Device
II	I-Device
incorporated	O
a	O
machine	B-General_Concept
code	I-General_Concept
monitor	I-General_Concept
with	O
commands	O
for	O
displaying	O
and	O
altering	O
the	O
computer	O
's	O
RAM	B-Architecture
,	O
either	O
one	O
byte	O
at	O
a	O
time	O
,	O
or	O
in	O
blocks	O
of	O
256	O
bytes	O
at	O
once	O
.	O
</s>
<s>
The	O
computer	O
powers	O
on	O
into	O
the	O
monitor	O
ROM	B-Device
,	O
displaying	O
a	O
*	O
prompt	O
.	O
</s>
<s>
Disk	O
software	O
can	O
be	O
booted	O
with	O
Ctrl+P	O
followed	O
by	O
6	O
,	O
referring	O
to	O
Slot	O
6	O
which	O
normally	O
contained	O
the	O
Disk	B-Device
II	I-Device
controller	O
.	O
</s>
<s>
A	O
6502	B-General_Concept
assembler	O
was	O
soon	O
offered	O
on	O
disk	O
,	O
and	O
later	O
the	O
UCSD	B-Language
compiler	I-Language
and	I-Language
operating	I-Language
system	I-Language
for	O
the	O
Pascal	B-Application
language	I-Application
were	O
made	O
available	O
.	O
</s>
<s>
The	O
Pascal	B-Application
system	O
requires	O
a	O
16KiB	O
RAM	B-Architecture
card	O
to	O
be	O
installed	O
in	O
the	O
language	O
card	O
position	O
(	O
expansion	B-Device
slot	I-Device
0	O
)	O
in	O
addition	O
to	O
the	O
full	O
48KiB	O
of	O
motherboard	O
memory	O
.	O
</s>
<s>
The	O
first	O
1,000	O
or	O
so	O
Apple	B-Device
IIs	I-Device
shipped	O
in	O
1977	O
with	O
a	O
68-page	O
mimeographed	O
"	O
Apple	B-Device
II	I-Device
Mini	O
Manual	O
"	O
,	O
hand-bound	O
with	O
brass	O
paper	O
fasteners	O
.	O
</s>
<s>
This	O
was	O
the	O
basis	O
for	O
the	O
Apple	B-Device
II	I-Device
Reference	O
Manual	O
,	O
which	O
became	O
known	O
as	O
the	O
Red	O
Book	O
for	O
its	O
red	O
cover	O
,	O
published	O
in	O
January	O
1978	O
.	O
</s>
<s>
The	O
Apple	B-Device
II	I-Device
Reference	O
Manual	O
contained	O
the	O
complete	O
schematic	O
of	O
the	O
entire	O
computer	O
's	O
circuitry	O
,	O
and	O
a	O
complete	O
source	O
listing	O
of	O
the	O
"	O
Monitor	O
"	O
ROM	B-Device
firmware	O
that	O
served	O
as	O
the	O
machine	O
's	O
BIOS	B-Operating_System
.	O
</s>
<s>
An	O
Apple	B-Device
II	I-Device
manual	O
signed	O
by	O
Steve	O
Jobs	O
in	O
1980	O
with	O
the	O
inscription	O
"	O
Julian	O
,	O
your	O
generation	O
is	O
the	O
first	O
to	O
grow	O
up	O
with	O
computers	O
.	O
</s>
<s>
The	O
original	O
Apple	B-Device
II	I-Device
provided	O
an	O
operating	B-General_Concept
system	I-General_Concept
in	O
ROM	B-Device
along	O
with	O
a	O
BASIC	O
variant	O
called	O
Integer	B-Language
BASIC	I-Language
.	O
</s>
<s>
The	O
only	O
form	O
of	O
storage	O
available	O
was	O
cassette	B-Architecture
tape	I-Architecture
which	O
was	O
inefficiently	O
slow	O
and	O
,	O
worse	O
,	O
unreliable	O
.	O
</s>
<s>
In	O
1977	O
when	O
Apple	O
decided	O
against	O
the	O
popular	O
but	O
clunky	O
CP/M	B-Application
operating	I-Application
system	I-Application
for	O
Wozniak	O
's	O
innovative	O
disk	O
controller	O
design	O
,	O
it	O
contracted	O
Shepardson	B-Device
Microsystems	I-Device
for	O
$	O
13,000	O
to	O
write	O
an	O
Apple	B-Operating_System
DOS	I-Operating_System
for	O
the	O
Apple	B-Device
II	I-Device
series	I-Device
.	O
</s>
<s>
Apple	O
's	O
Disk	B-Device
II	I-Device
-inch	O
floppy	B-Device
disk	I-Device
drive	I-Device
was	O
released	O
in	O
1978	O
.	O
</s>
<s>
The	O
final	O
and	O
most	O
popular	O
version	O
of	O
this	O
software	O
was	O
Apple	B-Operating_System
DOS	I-Operating_System
3.3	O
.	O
</s>
<s>
Apple	B-Operating_System
DOS	I-Operating_System
was	O
superseded	O
by	O
ProDOS	B-Operating_System
,	O
which	O
supported	O
a	O
hierarchical	O
filesystem	O
and	O
larger	O
storage	O
devices	O
.	O
</s>
<s>
With	O
an	O
optional	O
third-party	O
Z80-based	O
expansion	B-Device
card	I-Device
,	O
the	O
Apple	B-Device
II	I-Device
could	O
boot	O
into	O
the	O
CP/M	B-Application
operating	I-Application
system	I-Application
and	O
run	O
WordStar	B-Application
,	O
dBase	B-Application
II	I-Application
,	O
and	O
other	O
CP/M	B-Application
software	O
.	O
</s>
<s>
With	O
the	O
release	O
of	O
MousePaint	O
in	O
1984	O
and	O
the	O
Apple	B-Device
IIGS	I-Device
in	O
1986	O
,	O
the	O
platform	O
took	O
on	O
the	O
look	O
of	O
the	O
Macintosh	B-Device
user	O
interface	O
,	O
including	O
a	O
mouse	O
.	O
</s>
<s>
Apple	O
released	O
Applesoft	B-Language
BASIC	I-Language
in	O
1977	O
,	O
a	O
more	O
advanced	O
variant	O
of	O
the	O
language	O
which	O
users	O
could	O
run	O
instead	O
of	O
Integer	B-Language
BASIC	I-Language
for	O
more	O
capabilities	O
.	O
</s>
<s>
Some	O
commercial	O
Apple	B-Device
II	I-Device
software	O
booted	O
directly	O
and	O
did	O
not	O
use	O
standard	O
DOS	O
disk	O
formats	O
.	O
</s>
<s>
When	O
the	O
Apple	B-Device
II	I-Device
initially	O
shipped	O
in	O
June	O
1977	O
,	O
no	O
expansion	B-Device
cards	I-Device
were	O
available	O
for	O
the	O
slots	O
.	O
</s>
<s>
This	O
meant	O
that	O
the	O
user	O
did	O
not	O
have	O
any	O
way	O
of	O
connecting	O
a	O
modem	B-Application
or	O
a	O
printer	O
.	O
</s>
<s>
Wozniak	O
's	O
open-architecture	B-Architecture
design	O
and	O
Apple	B-Device
II	I-Device
's	O
multiple	O
expansion	B-Device
slots	I-Device
permitted	O
a	O
wide	O
variety	O
of	O
third-party	O
devices	O
,	O
including	O
peripheral	O
cards	O
,	O
such	O
as	O
serial	O
controllers	O
,	O
display	O
controllers	O
,	O
memory	O
boards	O
,	O
hard	O
disks	O
,	O
networking	O
components	O
,	O
and	O
real-time	B-Device
clocks	I-Device
.	O
</s>
<s>
There	O
were	O
plug-in	O
expansion	B-Device
cards	I-Device
—	O
such	O
as	O
the	O
Z-80	B-Device
SoftCard	I-Device
—	O
that	O
permitted	O
Apple	B-Device
II	I-Device
to	O
use	O
the	O
Z80	B-General_Concept
processor	O
and	O
run	O
programs	O
for	O
the	O
CP/M	B-Application
operating	I-Application
system	I-Application
,	O
including	O
the	O
dBase	B-Application
II	I-Application
database	O
and	O
the	O
WordStar	B-Application
word	O
processor	O
.	O
</s>
<s>
The	O
Z80	B-General_Concept
card	O
also	O
allowed	O
the	O
connection	O
to	O
a	O
modem	B-Application
,	O
and	O
thereby	O
to	O
any	O
networks	O
that	O
a	O
user	O
might	O
have	O
access	O
to	O
.	O
</s>
<s>
There	O
was	O
also	O
a	O
third-party	O
6809	B-Device
card	O
that	O
allowed	O
OS-9	B-Operating_System
Level	O
One	O
to	O
be	O
run	O
.	O
</s>
<s>
Apple	B-Device
II	I-Device
accelerator	O
cards	O
doubled	O
or	O
quadrupled	O
the	O
computer	O
's	O
speed	O
.	O
</s>
<s>
Early	O
Apple	B-Device
IIs	I-Device
were	O
often	O
sold	O
with	O
a	O
Sup'R'Mod	O
,	O
which	O
allowed	O
the	O
composite	O
video	O
signal	O
to	O
be	O
viewed	O
in	O
a	O
television	O
.	O
</s>
<s>
The	O
Soviet	O
Union	O
radio-electronics	O
industry	O
designed	O
Apple	O
II-compatible	O
computer	O
Agat	B-Device
.	O
</s>
<s>
Roughly	O
12,000	O
Agat	B-Device
7	O
and	O
9	O
models	O
were	O
produced	O
and	O
they	O
were	O
widely	O
used	O
in	O
Soviet	O
schools	O
.	O
</s>
<s>
Agat	B-Device
9	O
computers	O
could	O
run	O
"	O
Apple	B-Device
II	I-Device
"	O
compatibility	O
and	O
native	O
modes	O
.	O
</s>
<s>
"	O
Apple	B-Device
II	I-Device
"	O
mode	O
allowed	O
to	O
run	O
wider	O
variety	O
of	O
(	O
presumably	O
pirated	O
)	O
Apple	B-Device
II	I-Device
software	O
,	O
but	O
at	O
the	O
expense	O
of	O
less	O
RAM	B-Architecture
.	O
</s>
<s>
Because	O
of	O
that	O
Soviet	O
developers	O
preferred	O
native	O
mode	O
over	O
"	O
Apple	B-Device
II	I-Device
"	O
compatibility	O
mode	O
.	O
</s>
<s>
Jesse	O
Adams	O
Stein	O
wrote	O
,	O
"	O
As	O
the	O
first	O
company	O
to	O
release	O
a	O
'	O
consumer	O
appliance	O
 '	O
micro-computer	B-Architecture
,	O
Apple	O
Computer	O
offers	O
us	O
a	O
clear	O
view	O
of	O
this	O
shift	O
from	O
a	O
machine	O
to	O
an	O
appliance.	O
"	O
</s>
<s>
After	O
seeing	O
a	O
crude	O
,	O
wire-wrapped	O
prototype	O
demonstrated	O
by	O
Wozniak	O
and	O
Steve	O
Jobs	O
in	O
November	O
1976	O
,	O
Byte	O
predicted	O
in	O
April	O
1977	O
,	O
that	O
the	O
Apple	B-Device
II	I-Device
"	O
may	O
be	O
the	O
first	O
product	O
to	O
fully	O
qualify	O
as	O
the	O
'	O
appliance	O
computer	O
 '	O
...	O
a	O
completed	O
system	O
which	O
is	O
purchased	O
off	O
the	O
retail	O
shelf	O
,	O
taken	O
home	O
,	O
plugged	O
in	O
and	O
used	O
"	O
.	O
</s>
<s>
The	O
computer	O
's	O
color	B-Device
graphics	I-Device
capability	O
especially	O
impressed	O
the	O
magazine	O
.	O
</s>
<s>
The	O
magazine	O
published	O
a	O
favorable	O
review	O
of	O
the	O
computer	O
in	O
March	O
1978	O
,	O
concluding	O
:	O
"	O
For	O
the	O
user	O
that	O
wants	O
color	B-Device
graphics	I-Device
,	O
the	O
Apple	B-Device
II	I-Device
is	O
the	O
only	O
practical	O
choice	O
available	O
in	O
the	O
'	O
appliance	O
 '	O
computer	O
class.	O
"	O
</s>
<s>
Personal	O
Computer	O
World	O
in	O
August	O
1978	O
also	O
cited	O
the	O
color	O
capability	O
as	O
a	O
strength	O
,	O
stating	O
that	O
"	O
the	O
prime	O
reason	O
that	O
anyone	O
buys	O
an	O
Apple	B-Device
II	I-Device
must	O
surely	O
be	O
for	O
the	O
colour	O
graphics	O
"	O
.	O
</s>
<s>
The	O
author	O
concluded	O
that	O
"	O
the	O
Apple	B-Device
II	I-Device
is	O
a	O
very	O
promising	O
machine	O
"	O
which	O
"	O
would	O
be	O
even	O
more	O
of	O
a	O
temptation	O
were	O
its	O
price	O
slightly	O
lower	O
...	O
for	O
the	O
moment	O
,	O
colour	O
is	O
an	O
Apple	B-Device
II	I-Device
"	O
.	O
</s>
<s>
Sales	O
expanded	O
exponentially	O
into	O
the	O
business	O
and	O
professional	O
market	O
,	O
when	O
the	O
spreadsheet	O
program	O
VisiCalc	B-Application
was	O
launched	O
in	O
mid-1979	O
.	O
</s>
<s>
VisiCalc	B-Application
is	O
credited	O
as	O
the	O
defining	O
killer	O
app	O
in	O
the	O
microcomputer	B-Architecture
industry	O
.	O
</s>
<s>
During	O
this	O
period	O
the	O
sole	O
products	O
of	O
the	O
company	O
were	O
the	O
Apple	B-Device
II	I-Device
and	O
its	O
peripherals	O
,	O
accessories	O
,	O
and	O
software	O
.	O
</s>
