<s>
GEOS	B-Application
(	O
Graphic	O
Environment	O
Operating	B-General_Concept
System	I-General_Concept
)	O
is	O
a	O
discontinued	O
operating	B-General_Concept
system	I-General_Concept
from	O
Berkeley	O
Softworks	O
(	O
later	O
GeoWorks	B-Application
)	O
.	O
</s>
<s>
Originally	O
designed	O
for	O
the	O
Commodore	O
64	O
with	O
its	O
version	O
being	O
released	O
in	O
1986	O
,	O
enhanced	O
versions	O
of	O
GEOS	B-Application
later	O
became	O
available	O
in	O
1987	O
for	O
the	O
Commodore	B-Device
128	I-Device
and	O
in	O
1988	O
for	O
the	O
Apple	B-Device
II	I-Device
series	I-Device
of	O
computers	O
.	O
</s>
<s>
A	O
lesser-known	O
version	O
was	O
also	O
released	O
for	O
the	O
Commodore	B-Operating_System
Plus/4	I-Operating_System
.	O
</s>
<s>
GEOS	B-Application
closely	O
resembles	O
early	O
versions	O
of	O
the	O
classic	B-Application
Mac	I-Application
OS	I-Application
and	O
includes	O
a	O
graphical	O
word	B-General_Concept
processor	I-General_Concept
(	O
geoWrite	O
)	O
and	O
paint	O
program	O
(	O
geoPaint	O
)	O
.	O
</s>
<s>
'	O
s	O
Gazette	O
found	O
that	O
nearly	O
half	O
of	O
respondents	O
used	O
GEOS	B-Application
.	O
</s>
<s>
For	O
many	O
years	O
,	O
Commodore	O
bundled	O
GEOS	B-Application
with	O
its	O
redesigned	O
and	O
cost-reduced	O
C64	O
,	O
the	O
C64C	O
.	O
</s>
<s>
At	O
its	O
peak	O
,	O
GEOS	B-Application
was	O
the	O
third-most-popular	O
microcomputer	O
operating	B-General_Concept
system	I-General_Concept
in	O
the	O
world	O
in	O
terms	O
of	O
units	O
shipped	O
,	O
trailing	O
only	O
MS-DOS	B-Application
and	O
Mac	B-Application
OS	I-Application
(	O
besides	O
the	O
original	O
Commodore	O
64	O
's	O
KERNAL	B-Operating_System
)	O
.	O
</s>
<s>
Other	O
GEOS-compatible	O
software	O
packages	O
were	O
available	O
from	O
Berkeley	O
Softworks	O
or	O
from	O
third	O
parties	O
,	O
including	O
a	O
reasonably	O
sophisticated	O
desktop	O
publishing	O
application	O
called	O
geoPublish	B-Device
and	O
a	O
spreadsheet	O
called	O
geoCalc	O
.	O
</s>
<s>
While	O
geoPublish	B-Device
is	O
not	O
as	O
sophisticated	O
as	O
Aldus	B-Operating_System
Pagemaker	I-Operating_System
and	O
geoCalc	O
not	O
as	O
sophisticated	O
as	O
Microsoft	B-Application
Excel	I-Application
,	O
the	O
packages	O
provide	O
reasonable	O
functionality	O
,	O
and	O
Berkeley	O
Softworks	O
founder	O
Brian	O
Dougherty	O
claimed	O
the	O
company	O
ran	O
its	O
business	O
using	O
its	O
own	O
software	O
on	O
Commodore	O
8-bit	O
computers	O
for	O
several	O
years	O
.	O
</s>
<s>
Written	O
by	O
a	O
group	O
of	O
programmers	O
,	O
the	O
GEOS	B-Application
Design	O
Team	O
:	O
Jim	O
DeFrisco	O
,	O
Dave	O
Durran	O
,	O
Michael	O
Farr	O
,	O
Doug	O
Fults	O
,	O
Chris	O
Hawley	O
,	O
Clayton	O
Jung	O
,	O
and	O
Tony	O
Requist	O
,	O
led	O
by	O
Dougherty	O
,	O
who	O
cut	O
their	O
teeth	O
on	O
limited-resource	O
video	B-Device
game	I-Device
machines	I-Device
such	O
as	O
the	O
Atari	B-General_Concept
2600	I-General_Concept
,	O
GEOS	B-Application
was	O
revered	O
for	O
what	O
it	O
could	O
accomplish	O
on	O
machines	O
with	O
64	O
–	O
128kB	O
of	O
RAM	B-Architecture
memory	I-Architecture
and	O
1	O
–	O
2MHz	O
of	O
8-bit	O
processing	O
power	O
.	O
</s>
<s>
Unlike	O
many	O
pieces	O
of	O
proprietary	B-Application
software	I-Application
for	O
the	O
C64	O
and	O
C128	O
,	O
GEOS	B-Application
takes	O
full	O
advantage	O
of	O
many	O
of	O
the	O
add-ons	O
and	O
improvements	O
available	O
for	O
these	O
systems	O
.	O
</s>
<s>
Commodore	O
's	O
1351	B-Device
mouse	I-Device
is	O
supported	O
by	O
GEOS	B-Application
,	O
as	O
are	O
its	O
various	O
RAM	B-General_Concept
expansion	I-General_Concept
units	I-General_Concept
.	O
</s>
<s>
GEOS	B-Application
128	O
also	O
fully	O
supports	O
the	O
C128	O
's	O
640×200	O
high-resolution	O
VDC	O
display	O
mode	O
through	O
a	O
compatible	O
RGB	O
monitor	O
.	O
</s>
<s>
The	O
C64	O
version	O
of	O
GEOS	B-Application
incorporates	O
a	O
built-in	O
fast	B-Device
loader	I-Device
,	O
called	O
diskTurbo	B-Device
,	O
that	O
significantly	O
increases	O
the	O
speed	O
of	O
drive	O
access	O
on	O
the	O
slow	O
1541	B-Device
.	O
</s>
<s>
GEOS	B-Application
is	O
the	O
first	O
Commodore	O
software	O
that	O
could	O
use	O
a	O
floppy	O
disk	O
as	O
swap	O
space	O
or	O
virtual	B-Architecture
memory	I-Architecture
.	O
</s>
<s>
GEOS	B-Application
128	O
can	O
take	O
advantage	O
of	O
the	O
C128	O
's	O
enhanced	O
"	O
burst	O
mode	O
"	O
in	O
conjunction	O
with	O
the	O
1571	B-Device
and	O
1581	O
drives	O
.	O
</s>
<s>
The	O
Commodore	O
version	O
of	O
GEOS	B-Application
uses	O
a	O
copy	B-Application
protection	I-Application
scheme	O
that	O
renders	O
users	O
 '	O
disks	O
unbootable	O
if	O
it	O
detects	O
that	O
the	O
disk	O
has	O
been	O
illegally	O
duplicated	O
.	O
</s>
<s>
Via	O
Berkeley	O
's	O
special	O
geoCable	O
interface	O
converter	O
or	O
other	O
third-party	O
interfaces	O
to	O
connect	O
standard	O
RS-232	O
or	O
Centronics	O
printers	O
to	O
the	O
Commodore	O
serial	O
bus	O
,	O
GEOS	B-Application
supports	O
a	O
wide	O
variety	O
of	O
printers	O
,	O
including	O
HP	O
PCL	O
printers	O
and	O
the	O
Apple	O
LaserWriter	O
.	O
</s>
<s>
This	O
ability	O
to	O
print	O
to	O
high-end	O
printers	O
was	O
a	O
major	O
factor	O
in	O
making	O
GEOS	B-Application
a	O
desktop	O
publishing	O
platform	O
.	O
</s>
<s>
The	O
Apple	B-Device
II	I-Device
version	O
of	O
GEOS	B-Application
was	O
released	O
as	O
freeware	B-License
in	O
August	O
2003	O
.	O
</s>
<s>
The	O
latest	O
GEOS	B-Application
desktop	O
suite	O
for	O
IBM	O
PC	O
compatibles	O
is	O
Breadbox	B-Application
Ensemble	I-Application
.	O
</s>
<s>
Nokia	O
used	O
GEOS	B-Application
as	O
a	O
base	O
operating	B-General_Concept
system	I-General_Concept
for	O
their	O
Nokia	B-Operating_System
Communicator	I-Operating_System
series	O
,	O
before	O
switching	O
to	O
EPOC	B-Language
(	O
Symbian	B-Operating_System
)	O
.	O
</s>
<s>
On	O
August	O
19	O
,	O
2016	O
,	O
Michael	O
Steil	O
posted	O
in	O
his	O
blog	O
that	O
the	O
source	O
code	O
for	O
GEOS	B-Application
2.0	O
for	O
Commodore	O
C64	O
had	O
been	O
fully	O
reverse-engineered	O
and	O
suitable	O
for	O
the	O
cc65	O
compiler	O
suite	O
.	O
</s>
<s>
The	O
reverse-engineered	O
source	O
code	O
has	O
been	O
made	O
available	O
at	O
GitHub	B-Application
.	O
</s>
<s>
Dozens	O
of	O
official	O
and	O
third-party	O
applications	O
and	O
other	O
products	O
were	O
produced	O
for	O
GEOS	B-Application
.	O
</s>
