<s>
Pintos	B-Application
is	O
computer	O
software	O
,	O
a	O
simple	O
instructional	O
operating	B-General_Concept
system	I-General_Concept
framework	O
for	O
the	O
x86	B-Operating_System
instruction	B-General_Concept
set	I-General_Concept
architecture	I-General_Concept
.	O
</s>
<s>
It	O
supports	O
kernel	B-Operating_System
threads	B-Operating_System
,	O
loading	O
and	O
running	O
user	O
programs	B-Application
,	O
and	O
a	O
file	B-Application
system	I-Application
,	O
but	O
it	O
implements	O
all	O
of	O
these	O
in	O
a	O
very	O
simple	O
way	O
.	O
</s>
<s>
Pintos	B-Application
is	O
currently	O
used	O
by	O
multiple	O
institutions	O
,	O
including	O
UT	O
Austin	O
,	O
UC	O
Berkeley	O
and	O
Imperial	O
College	O
London	O
,	O
as	O
an	O
academic	O
aid	O
in	O
Operating	B-General_Concept
Systems	I-General_Concept
class	O
curriculums	O
.	O
</s>
<s>
It	O
originated	O
as	O
a	O
replacement	O
for	O
Not	B-Operating_System
Another	I-Operating_System
Completely	I-Operating_System
Heuristic	I-Operating_System
Operating	I-Operating_System
System	I-Operating_System
(	O
Nachos	O
)	O
,	O
a	O
similar	O
system	O
originally	O
developed	O
at	O
UC	O
Berkeley	O
by	O
Thomas	O
E	O
.	O
Anderson	O
,	O
and	O
was	O
designed	O
along	O
similar	O
lines	O
.	O
</s>
<s>
Like	O
Nachos	O
,	O
Pintos	B-Application
is	O
intended	O
to	O
introduce	O
undergraduates	O
to	O
concepts	O
in	O
operating	B-General_Concept
system	I-General_Concept
design	O
and	O
implementation	O
by	O
requiring	O
them	O
to	O
implement	O
significant	O
portions	O
of	O
a	O
real	O
operating	B-General_Concept
system	I-General_Concept
,	O
including	O
thread	B-Operating_System
and	O
memory	O
management	O
and	O
file	B-Application
system	I-Application
access	O
.	O
</s>
<s>
Pintos	B-Application
also	O
teaches	O
students	O
valuable	O
debugging	O
skills	O
.	O
</s>
<s>
Unlike	O
Nachos	O
,	O
Pintos	B-Application
can	O
run	O
on	O
actual	O
x86	B-Operating_System
hardware	O
,	O
though	O
it	O
is	O
often	O
run	O
atop	O
an	O
x86	B-Operating_System
emulator	O
,	O
such	O
as	O
Bochs	B-Language
or	O
QEMU	B-Application
.	O
</s>
<s>
Nachos	O
,	O
by	O
contrast	O
,	O
runs	O
as	O
a	O
user	O
process	O
on	O
a	O
host	O
operating	B-General_Concept
system	I-General_Concept
,	O
and	O
targets	O
the	O
MIPS	B-Device
architecture	I-Device
(	O
Nachos	O
code	O
must	O
run	O
atop	O
a	O
MIPS	O
simulator	O
)	O
.	O
</s>
<s>
Pintos	B-Application
and	O
its	O
accompanying	O
assignments	O
are	O
also	O
written	O
in	O
the	O
programming	B-Language
language	I-Language
C	I-Language
instead	O
of	O
C++	B-Language
(	O
used	O
for	O
original	O
Nachos	O
)	O
or	O
Java	B-Language
(	O
used	O
for	O
Nachos	O
5.0j	O
)	O
.	O
</s>
