<s>
GS/OS	B-Application
is	O
an	O
operating	B-General_Concept
system	I-General_Concept
developed	O
by	O
Apple	O
Computer	O
for	O
its	O
Apple	B-Device
IIGS	I-Device
personal	B-Device
computer	I-Device
.	O
</s>
<s>
It	O
provides	O
facilities	O
for	O
accessing	O
the	O
file	B-Application
system	I-Application
,	O
controlling	O
input/output	O
devices	O
,	O
loading	O
and	O
running	O
program	O
files	O
,	O
and	O
a	O
system	O
allowing	O
programs	O
to	O
handle	O
interrupts	B-Application
and	O
signals	O
.	O
</s>
<s>
It	O
uses	O
ProDOS	B-Operating_System
as	O
its	O
primarily	O
filing	O
system	O
.	O
</s>
<s>
GS/OS	B-Application
is	O
a	O
component	O
of	O
Apple	B-Device
IIGS	I-Device
System	B-Application
Software	I-Application
versions	O
4.0	O
through	O
6.0.1	O
,	O
and	O
was	O
the	O
first	O
true	O
16-bit	O
operating	B-General_Concept
system	I-General_Concept
for	O
the	O
IIGS	B-Device
.	O
</s>
<s>
The	O
advantage	O
of	O
GS/OS	B-Application
over	O
its	O
predecessor	O
,	O
the	O
ProDOS	B-Operating_System
16	I-Operating_System
operating	B-General_Concept
system	I-General_Concept
,	O
is	O
that	O
it	O
was	O
written	O
entirely	O
in	O
16-bit	O
code	O
for	O
the	O
65816	B-General_Concept
processor	O
used	O
in	O
the	O
IIGS	B-Device
,	O
rather	O
than	O
primarily	O
in	O
8-bit	O
6502	B-General_Concept
machine	O
code	O
that	O
does	O
not	O
take	O
advantage	O
of	O
the	O
IIGS	B-Device
's	O
unique	O
features	O
.	O
</s>
<s>
This	O
in	O
turn	O
allows	O
GS/OS	B-Application
to	O
offers	O
vast	O
speed	O
optimizations	O
(	O
loading	O
time	O
,	O
disk	O
access	O
,	O
screen	O
updates	O
)	O
compared	O
with	O
the	O
previous	O
OS	O
,	O
and	O
provided	O
room	O
to	O
incorporate	O
many	O
features	O
of	O
other	O
Apple	O
operating	B-General_Concept
systems	I-General_Concept
,	O
including	O
Apple	B-Device
III	I-Device
Apple	B-Operating_System
SOS	I-Operating_System
,	O
the	O
Macintosh	B-Application
System	I-Application
5	O
,	O
as	O
well	O
as	O
concepts	O
and	O
features	O
that	O
would	O
later	O
appear	O
in	O
future	O
Macintosh	B-Application
System	I-Application
Software	I-Application
releases	O
(	O
e.g.	O
</s>
<s>
In	O
addition	O
to	O
continued	O
enhancements	O
to	O
the	O
IIGS	B-Device
Finder	B-Application
and	O
loadable	O
fonts	O
,	O
GS/OS	B-Application
offered	O
plug-in	O
device	O
drivers	O
(	O
modem	O
,	O
printer	O
,	O
etc	O
.	O
</s>
<s>
)	O
,	O
a	O
thermometer	O
progress	O
display	O
,	O
AppleShare	O
support	O
,	O
File	B-Application
System	I-Application
Translators	O
for	O
accessing	O
foreign	O
file	O
formats	O
,	O
disk	O
caching	O
and	O
support	O
for	O
storage	O
devices	O
up	O
to	O
4	O
Gigabytes	O
.	O
</s>
<s>
It	O
also	O
extends	O
the	O
ProDOS	B-Operating_System
file	B-Application
system	I-Application
to	O
provide	O
for	O
resource	B-Operating_System
forks	I-Operating_System
on	O
files	O
similar	O
to	O
those	O
used	O
on	O
the	O
Apple	B-Device
Macintosh	I-Device
,	O
which	O
allows	O
for	O
programs	O
to	O
be	O
written	O
in	O
a	O
more	O
flexible	O
way	O
.	O
</s>
<s>
The	O
newly	O
included	O
Apple	O
Advanced	O
Disk	O
Utilities	O
and	O
Apple	B-Device
IIGS	I-Device
Installer	O
helped	O
facilitate	O
partitioning	O
,	O
formatting	O
and	O
installing	O
software	O
and	O
drivers	O
with	O
visual	O
ease	O
.	O
</s>
<s>
A	O
command-line	O
development	O
environment	O
called	O
APW	O
(	O
Apple	O
Programmer	O
's	O
Workshop	O
)	O
is	O
available	O
;	O
much	O
like	O
the	O
Macintosh	B-Operating_System
Programmer	I-Operating_System
's	I-Operating_System
Workshop	I-Operating_System
.	O
</s>
<s>
GS/OS	B-Application
includes	O
a	O
unique	O
facility	O
known	O
as	O
file	B-Application
system	I-Application
translators	O
(	O
FSTs	O
)	O
which	O
allows	O
it	O
to	O
support	O
multiple	O
on-disk	O
file	O
systems	O
in	O
a	O
manner	O
transparent	O
to	O
application	O
programs	O
,	O
a	O
feature	O
not	O
found	O
in	O
ProDOS	B-Operating_System
or	O
most	O
other	O
microcomputer	O
operating	B-General_Concept
systems	I-General_Concept
at	O
the	O
time	O
.	O
</s>
<s>
It	O
was	O
usually	O
used	O
with	O
the	O
ProDOS	B-Operating_System
file	B-Application
system	I-Application
(	O
which	O
was	O
the	O
only	O
one	O
from	O
which	O
it	O
could	O
be	O
booted	O
)	O
,	O
but	O
GS/OS	B-Application
also	O
supports	O
a	O
variety	O
of	O
other	O
file	B-Application
systems	I-Application
,	O
including	O
the	O
Hierarchical	B-Application
File	I-Application
System	I-Application
used	O
by	O
the	O
Mac	B-Application
OS	I-Application
.	O
</s>
<s>
Other	O
file	B-Application
system	I-Application
translators	O
,	O
in	O
addition	O
to	O
ProDOS	B-Operating_System
and	O
HFS	B-Application
,	O
include	O
those	O
for	O
MS-DOS	B-Application
,	O
High	O
Sierra/ISO	O
-9660	O
,	O
Apple	B-Operating_System
DOS	I-Operating_System
3.3	O
,	O
and	O
Pascal	O
,	O
albeit	O
read-only	O
(	O
full	O
read/write	O
support	O
had	O
been	O
planned	O
but	O
never	O
completed	O
)	O
.	O
</s>
