<s>
VisiCalc	B-Application
(	O
"	O
visible	O
calculator	O
"	O
)	O
is	O
the	O
first	O
spreadsheet	B-Application
computer	B-Application
program	I-Application
for	O
personal	B-Device
computers	I-Device
,	O
originally	O
released	O
for	O
Apple	B-Device
II	I-Device
by	O
VisiCorp	O
on	O
October	O
17	O
,	O
1979	O
.	O
</s>
<s>
It	O
is	O
considered	O
the	O
killer	O
application	O
for	O
the	O
Apple	B-Device
II	I-Device
,	O
turning	O
the	O
microcomputer	B-Architecture
from	O
a	O
hobby	O
for	O
computer	O
enthusiasts	O
into	O
a	O
serious	O
business	O
tool	O
,	O
and	O
then	O
prompting	O
IBM	O
to	O
introduce	O
the	O
IBM	B-Device
PC	I-Device
two	O
years	O
later	O
.	O
</s>
<s>
Initially	O
developed	O
for	O
the	O
Apple	B-Device
II	I-Device
computer	O
using	O
a	O
6502	B-General_Concept
assembler	B-Application
running	O
on	O
the	O
Multics	B-Application
time	B-General_Concept
sharing	I-General_Concept
system	O
,	O
VisiCalc	B-Application
was	O
ported	O
to	O
numerous	O
platforms	B-Device
,	O
both	O
8-bit	O
and	O
some	O
of	O
the	O
early	O
16-bit	O
systems	O
.	O
</s>
<s>
To	O
do	O
this	O
,	O
the	O
company	O
developed	O
porting	O
platforms	B-Device
that	O
produced	O
bug	B-General_Concept
compatible	I-General_Concept
versions	O
.	O
</s>
<s>
The	O
company	O
took	O
the	O
same	O
approach	O
when	O
the	O
IBM	B-Device
PC	I-Device
was	O
launched	O
,	O
producing	O
a	O
product	O
that	O
was	O
essentially	O
identical	O
to	O
the	O
original	O
8-bit	O
Apple	B-Device
II	I-Device
version	O
.	O
</s>
<s>
VisiCalc	B-Application
uses	O
the	O
A1	O
notation	O
in	O
formulas	O
.	O
</s>
<s>
When	O
Lotus	B-Application
1-2-3	I-Application
was	O
launched	O
in	O
1983	O
,	O
taking	O
full	O
advantage	O
of	O
the	O
expanded	O
memory	O
and	O
screen	O
of	O
the	O
PC	O
,	O
VisiCalc	B-Application
sales	O
ended	O
almost	O
overnight	O
.	O
</s>
<s>
Lotus	O
Development	O
purchased	O
the	O
company	O
in	O
1985	O
,	O
and	O
immediately	O
ended	O
sales	O
of	O
VisiCalc	B-Application
and	O
the	O
company	O
's	O
other	O
products	O
.	O
</s>
<s>
Dan	O
Bricklin	O
conceived	O
VisiCalc	B-Application
while	O
watching	O
a	O
presentation	O
at	O
Harvard	O
Business	O
School	O
.	O
</s>
<s>
Bricklin	O
realized	O
that	O
he	O
could	O
replicate	O
the	O
process	O
on	O
a	O
computer	O
using	O
an	O
"	O
electronic	O
spreadsheet	B-Application
"	O
to	O
view	O
results	O
of	O
underlying	O
formulae	O
.	O
</s>
<s>
Bob	O
Frankston	O
joined	O
Bricklin	O
at	O
231	O
Broadway	O
,	O
Arlington	O
,	O
Massachusetts	O
,	O
and	O
the	O
pair	O
formed	O
the	O
Software	O
Arts	O
company	O
,	O
and	O
developed	O
the	O
VisiCalc	B-Application
program	O
in	O
two	O
months	O
during	O
the	O
winter	O
of	O
1978	O
–	O
79	O
.	O
</s>
<s>
Bricklin	O
was	O
referring	O
to	O
the	O
variety	O
of	O
report	B-General_Concept
generators	I-General_Concept
that	O
were	O
in	O
use	O
at	O
that	O
time	O
,	O
including	O
Business	O
Planning	O
Language	O
(	O
BPL	O
)	O
from	O
International	O
Timesharing	B-General_Concept
Corporation	O
(	O
ITS	O
)	O
and	O
Foresight	O
from	O
Foresight	O
Systems	O
.	O
</s>
<s>
However	O
,	O
these	O
earlier	O
timesharing	B-General_Concept
programs	O
were	O
not	O
completely	O
interactive	O
,	O
and	O
they	O
pre-dated	O
personal	B-Device
computers	I-Device
.	O
</s>
<s>
Frankston	O
described	O
VisiCalc	B-Application
as	O
a	O
"	O
magic	O
sheet	O
of	O
paper	O
that	O
can	O
perform	O
calculations	O
and	O
recalculations	O
 [ which ] 	O
allows	O
the	O
user	O
to	O
just	O
solve	O
the	O
problem	O
using	O
familiar	O
tools	O
and	O
concepts	O
"	O
.	O
</s>
<s>
The	O
Personal	O
Software	O
company	O
began	O
selling	O
VisiCalc	B-Application
in	O
mid-1979	O
for	O
under	O
,	O
after	O
a	O
demonstration	O
at	O
the	O
fourth	O
West	O
Coast	O
Computer	O
Faire	O
and	O
an	O
official	O
launch	O
on	O
June4	O
at	O
the	O
National	O
Computer	O
Conference	O
.	O
</s>
<s>
It	O
requires	O
an	O
Apple	B-Device
II	I-Device
with	O
32K	O
of	O
random-access	B-Architecture
memory	I-Architecture
(	O
RAM	B-Architecture
)	O
,	O
and	O
supports	O
saving	O
files	O
to	O
magnetic	O
tape	B-Device
cassette	I-Device
or	O
to	O
the	O
Apple	B-Device
Disk	I-Device
II	I-Device
floppy	O
disk	O
system	O
.	O
</s>
<s>
VisiCalc	B-Application
was	O
unusually	O
easy	O
to	O
use	O
and	O
came	O
with	O
excellent	O
documentation	O
.	O
</s>
<s>
Ben	O
Rosen	O
speculated	O
in	O
July	O
1979	O
,	O
that	O
"	O
VisiCalc	B-Application
could	O
someday	O
become	O
the	O
software	O
tail	O
that	O
wags	O
(	O
and	O
sells	O
)	O
the	O
personal	B-Device
computer	I-Device
dog	O
"	O
.	O
</s>
<s>
For	O
the	O
first	O
12	O
months	O
,	O
it	O
was	O
only	O
available	O
for	O
Apple	B-Device
II	I-Device
,	O
and	O
became	O
its	O
killer	O
app	O
.	O
</s>
<s>
John	O
Markoff	O
wrote	O
that	O
the	O
computer	O
was	O
sold	O
as	O
a	O
"	O
VisiCalc	B-Application
accessory	O
"	O
,	O
and	O
many	O
bought	O
Apple	O
computers	O
to	O
run	O
the	O
$100	O
software	O
—	O
more	O
than	O
25%	O
of	O
those	O
sold	O
in	O
1979	O
were	O
reportedly	O
for	O
VisiCalc	B-Application
—	O
even	O
if	O
they	O
already	O
owned	O
other	O
computers	O
.	O
</s>
<s>
Steve	O
Wozniak	O
said	O
that	O
small	O
businesses	O
,	O
not	O
the	O
hobbyists	O
he	O
and	O
Steve	O
Jobs	O
had	O
expected	O
,	O
purchased	O
90%	O
of	O
Apple	B-Device
IIs	I-Device
.	O
</s>
<s>
Apple	O
's	O
rival	O
Tandy	O
Corporation	O
used	O
VisiCalc	B-Application
on	O
Apple	B-Device
IIs	I-Device
at	O
their	O
headquarters	O
.	O
</s>
<s>
Other	O
software	O
supports	O
its	O
Data	B-Protocol
Interchange	I-Protocol
Format	I-Protocol
(	O
DIF	O
)	O
to	O
share	O
data	O
.	O
</s>
<s>
One	O
example	O
is	O
the	O
Microsoft	B-Language
BASIC	I-Language
interpreter	O
supplied	O
with	O
most	O
microcomputers	B-Architecture
that	O
run	O
VisiCalc	B-Application
.	O
</s>
<s>
This	O
allows	O
skilled	O
BASIC	O
programmers	O
to	O
write	O
features	O
,	O
such	O
as	O
trigonometric	O
functions	O
,	O
that	O
VisiCalc	B-Application
lacks	O
.	O
</s>
<s>
However	O
,	O
Apple	O
eventually	O
began	O
shipping	O
all	O
Apple	B-Device
IIs	I-Device
with	O
48k	O
memory	O
following	O
a	O
drop	O
in	O
RAM	B-Architecture
prices	O
,	O
enabling	O
the	O
developers	O
to	O
include	O
more	O
features	O
.	O
</s>
<s>
The	O
initial	O
release	O
supported	O
tape	B-Device
cassette	I-Device
storage	O
,	O
but	O
that	O
was	O
quickly	O
dropped	O
.	O
</s>
<s>
At	O
VisiCalc	B-Application
's	O
release	O
,	O
Personal	O
Software	O
promised	O
to	O
port	O
the	O
program	O
to	O
other	O
computers	O
,	O
starting	O
with	O
those	O
with	O
the	O
MOS	B-General_Concept
Technology	I-General_Concept
6502	I-General_Concept
microprocessor	O
,	O
and	O
versions	O
appeared	O
for	O
Atari	B-Device
800	I-Device
and	O
Commodore	B-Device
PET	I-Device
.	O
</s>
<s>
Both	O
of	O
those	O
were	O
easy	O
,	O
because	O
those	O
computers	O
have	O
the	O
same	O
CPU	O
as	O
Apple	B-Device
II	I-Device
,	O
and	O
large	O
portions	O
of	O
code	O
were	O
reused	O
.	O
</s>
<s>
The	O
PET	O
only	O
has	O
32k	O
versus	O
Apple	B-Device
II	I-Device
's	O
available	O
48k	O
.	O
</s>
<s>
Other	O
ports	O
followed	O
for	O
Apple	B-Device
III	I-Device
,	O
the	O
Zilog	O
Z80-based	O
Tandy	B-Device
TRS-80	I-Device
Model	O
I	O
,	O
Model	B-Device
II	I-Device
,	O
Model	O
III	O
,	O
Model	B-Device
4	I-Device
,	O
and	O
Sony	O
SMC-70	O
.	O
</s>
<s>
The	O
TRS-80	B-Device
Model	I-Device
I	I-Device
and	O
Sony	O
SMC-70	O
ports	O
are	O
the	O
only	O
versions	O
of	O
VisiCalc	B-Application
without	O
copy	B-Application
protection	I-Application
.	O
</s>
<s>
The	O
Sony	O
SMC-70	O
port	O
is	O
the	O
only	O
CP/M	B-Application
version	O
.	O
</s>
<s>
Most	O
versions	O
are	O
disk-based	O
,	O
but	O
the	O
PET	O
VisiCalc	B-Application
came	O
with	O
a	O
ROM	B-Device
chip	I-Device
that	O
the	O
user	O
must	O
install	O
in	O
one	O
of	O
the	O
motherboard	O
's	O
expansion	O
ROM	O
sockets	O
.	O
</s>
<s>
The	O
most	O
important	O
port	O
is	O
for	O
the	O
IBM	B-Device
PC	I-Device
,	O
and	O
VisiCalc	B-Application
became	O
one	O
of	O
the	O
first	O
commercial	B-Application
packages	O
available	O
when	O
the	O
IBM	B-Device
PC	I-Device
shipped	O
in	O
1981	O
.	O
</s>
<s>
It	O
quickly	O
became	O
a	O
best-seller	O
on	O
this	O
platform	O
,	O
though	O
severely	O
limited	O
to	O
be	O
compatible	O
with	O
the	O
versions	O
for	O
the	O
8-bit	O
platforms	B-Device
.	O
</s>
<s>
By	O
1982	O
,	O
VisiCalc	B-Application
's	O
price	O
had	O
risen	O
from	O
$100	O
to	O
.	O
</s>
<s>
Several	O
competitors	O
appeared	O
in	O
the	O
market	O
,	O
such	O
as	O
SuperCalc	B-Application
and	O
Multiplan	B-Device
,	O
each	O
of	O
which	O
have	O
more	O
features	O
and	O
corrected	O
deficiencies	O
in	O
VisiCalc	B-Application
,	O
but	O
could	O
not	O
overcome	O
its	O
market	O
dominance	O
.	O
</s>
<s>
A	O
more	O
dramatic	O
change	O
occurred	O
with	O
the	O
1983	O
launch	O
of	O
Lotus	O
Development	O
Corporation	O
's	O
Lotus	B-Application
1-2-3	I-Application
,	O
created	O
by	O
former	O
Personal	O
Software/VisiCorp	O
employee	O
Mitch	O
Kapor	O
,	O
who	O
had	O
written	O
VisiTrend	O
and	O
VisiPlot	O
.	O
</s>
<s>
Unlike	O
the	O
IBM	B-Device
PC	I-Device
version	O
of	O
VisiCalc	B-Application
,	O
1-2-3	O
was	O
written	O
to	O
take	O
full	O
advantage	O
of	O
the	O
PC	O
's	O
increased	O
memory	O
,	O
screen	O
,	O
and	O
performance	O
.	O
</s>
<s>
Yet	O
it	O
was	O
designed	O
to	O
be	O
as	O
compatible	O
as	O
possible	O
with	O
VisiCalc	B-Application
,	O
including	O
the	O
menu	O
structure	O
,	O
to	O
allow	O
VisiCalc	B-Application
users	O
to	O
easily	O
migrate	O
to	O
1-2-3	O
.	O
</s>
<s>
1-2-3	O
was	O
almost	O
immediately	O
successful	O
,	O
and	O
in	O
1984	O
,	O
InfoWorld	O
wrote	O
that	O
sales	O
of	O
VisiCalc	B-Application
were	O
"	O
rapidly	O
declining	O
"	O
,	O
stating	O
,	O
that	O
it	O
was	O
"	O
the	O
first	O
successful	O
software	O
product	O
to	O
have	O
gone	O
through	O
a	O
complete	O
life	O
cycle	O
,	O
from	O
conception	O
in	O
1978	O
to	O
introduction	O
in	O
1979	O
to	O
peak	O
success	O
in	O
1982	O
to	O
decline	O
in	O
1983	O
to	O
a	O
probable	O
death	O
according	O
to	O
industry	O
insiders	O
in	O
1984	O
"	O
.	O
</s>
<s>
The	O
magazine	O
added	O
that	O
the	O
company	O
was	O
slow	O
to	O
upgrade	O
the	O
software	O
,	O
only	O
releasing	O
an	O
Advanced	O
Version	O
of	O
VisiCalc	B-Application
for	O
Apple	B-Device
II	I-Device
in	O
1983	O
,	O
and	O
announcing	O
one	O
for	O
the	O
IBM	B-Device
PC	I-Device
in	O
1984	O
.	O
</s>
<s>
1983	O
:	O
Enhanced	O
VisiCalc	B-Application
for	O
TRS-80	B-Device
Model	I-Device
4	I-Device
,	O
Model	B-Device
II	I-Device
(	O
with	O
RAM	B-Architecture
expansion	O
card	O
)	O
and	O
Model	O
16	O
.	O
</s>
<s>
In	O
1983	O
,	O
Softline	O
readers	O
named	O
VisiCalc	B-Application
tenth	O
overall	O
and	O
the	O
highest	O
non-game	O
on	O
the	O
magazine	O
's	O
Top	O
Thirty	O
list	O
of	O
Atari	B-Device
8-bit	I-Device
programs	O
by	O
popularity	O
.	O
</s>
<s>
II	O
Computing	O
listed	O
it	O
second	O
on	O
the	O
magazine	O
's	O
list	O
of	O
top	O
Apple	B-Device
II	I-Device
software	O
as	O
of	O
late	O
1985	O
,	O
based	O
on	O
sales	O
and	O
market-share	O
data	O
.	O
</s>
<s>
In	O
its	O
1980	O
review	O
,	O
BYTE	B-Application
wrote	O
"	O
The	O
most	O
exciting	O
and	O
influential	O
piece	O
of	O
software	O
that	O
has	O
been	O
written	O
for	O
any	O
microcomputer	B-Architecture
application	O
is	O
VisiCalc	B-Application
"	O
.	O
</s>
<s>
It	O
concluded	O
,	O
"	O
VisiCalc	B-Application
is	O
the	O
first	O
program	O
available	O
on	O
a	O
microcomputer	B-Architecture
that	O
has	O
been	O
responsible	O
for	O
sales	O
of	O
entire	O
systems	O
"	O
.	O
</s>
<s>
Creative	B-General_Concept
Computings	I-General_Concept
review	O
that	O
year	O
similarly	O
concluded	O
,	O
"	O
for	O
almost	O
anyone	O
in	O
business	O
,	O
education	O
,	O
or	O
any	O
science-related	O
field	O
it	O
is	O
...	O
reason	O
enough	O
to	O
purchase	O
a	O
small	O
computer	O
system	O
in	O
the	O
first	O
place	O
"	O
.	O
</s>
<s>
reported	O
,	O
"	O
Every	O
Visicalc	B-Application
user	O
knows	O
of	O
someone	O
who	O
purchased	O
an	O
Apple	O
just	O
to	O
be	O
able	O
to	O
use	O
Visicalc	B-Application
"	O
.	O
</s>
<s>
Antic	O
wrote	O
in	O
1984	O
,	O
"	O
VisiCalc	B-Application
is	O
n't	O
as	O
easy	O
to	O
use	O
as	O
prepackaged	O
home	O
accounting	O
programs	O
,	O
because	O
you	O
're	O
required	O
to	O
design	O
both	O
the	O
layout	O
and	O
the	O
formulas	O
used	O
by	O
the	O
program	O
.	O
</s>
<s>
You	O
can	O
use	O
VisiCalc	B-Application
to	O
balance	O
your	O
checkbook	O
,	O
keep	O
track	O
of	O
credit	O
card	O
purchases	O
,	O
calculate	O
your	O
net	O
worth	O
,	O
do	O
your	O
taxes	O
—	O
the	O
possibilities	O
are	O
practically	O
limitless.	O
"	O
</s>
<s>
In	O
2006	O
,	O
Charles	O
Babcock	O
of	O
InformationWeek	O
wrote	O
that	O
,	O
in	O
retrospect	O
,	O
"	O
VisiCalc	B-Application
was	O
flawed	O
and	O
clunky	O
,	O
and	O
could	O
n't	O
do	O
many	O
things	O
users	O
wanted	O
it	O
to	O
do	O
"	O
,	O
but	O
also	O
,	O
"	O
It	O
's	O
great	O
because	O
it	O
demonstrated	O
the	O
power	O
of	O
personal	O
computing.	O
"	O
</s>
<s>
Since	O
2010	O
,	O
the	O
anniversary	O
of	O
the	O
October	O
17	O
,	O
1979	O
,	O
launch	O
of	O
VisiCalc	B-Application
has	O
been	O
celebrated	O
as	O
Spreadsheet	B-Application
Day	O
.	O
</s>
<s>
VisiCalc	B-Application
is	O
one	O
of	O
the	O
earliest	O
examples	O
of	O
metaphor-driven	B-Architecture
user	I-Architecture
interface	I-Architecture
design	I-Architecture
,	O
due	O
to	O
its	O
resemblance	O
with	O
paper	O
spreadsheets	B-Application
.	O
</s>
<s>
This	O
metaphor	O
made	O
the	O
program	O
comprehensible	O
and	O
familiar	O
to	O
accountants	O
,	O
economists	O
,	O
and	O
bookkeepers	O
who	O
were	O
not	O
used	O
to	O
using	O
computers	O
,	O
and	O
VisiCalc	B-Application
's	O
release	O
marked	O
the	O
point	O
where	O
"	O
personal	B-Device
computers	I-Device
crossed	O
the	O
line	O
from	O
a	O
hobbyist	O
obsession	O
to	O
a	O
compelling	O
tool	O
"	O
.	O
</s>
<s>
Compared	O
to	O
paper	O
spreadsheets	B-Application
,	O
VisiCalc	B-Application
freed	O
users	O
to	O
change	O
numbers	O
without	O
having	O
to	O
recalculate	O
the	O
whole	O
spreadsheet	B-Application
by	O
hand	O
,	O
which	O
,	O
according	O
to	O
Steven	O
Levy	O
,	O
"	O
changed	O
the	O
perception	O
of	O
a	O
spreadsheet	B-Application
from	O
a	O
document	O
of	O
hard	O
costs	O
into	O
a	O
modeling	O
tool	O
by	O
which	O
one	O
tested	O
business	O
scenarios	O
"	O
.	O
</s>
