<s>
Sprite	B-Operating_System
is	O
an	O
experimental	O
Unix-like	B-Operating_System
distributed	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
developed	O
at	O
the	O
University	O
of	O
California	O
,	O
Berkeley	O
by	O
John	O
Ousterhout	O
's	O
research	O
group	O
between	O
1984	O
and	O
1992	O
.	O
</s>
<s>
Its	O
notable	O
features	O
include	O
support	O
for	O
single	B-Operating_System
system	I-Operating_System
image	I-Operating_System
on	O
computer	B-Architecture
clusters	I-Architecture
and	O
the	O
introduction	O
of	O
the	O
log-structured	B-Application
filesystem	I-Application
.	O
</s>
<s>
The	O
Tcl	B-Operating_System
scripting	O
language	O
also	O
originated	O
in	O
this	O
project	O
.	O
</s>
<s>
Early	O
work	O
on	O
Sprite	B-Operating_System
was	O
based	O
on	O
the	O
idea	O
of	O
making	O
the	O
operating	O
system	O
more	O
"	O
network	O
aware	O
"	O
,	O
and	O
thereby	O
at	O
the	O
same	O
time	O
make	O
it	O
invisible	O
to	O
the	O
user	O
.	O
</s>
<s>
Many	O
of	O
the	O
key	O
Unix	B-Application
files	O
are	O
based	O
on	O
the	O
network	O
,	O
including	O
things	O
like	O
the	O
password	O
file	O
.	O
</s>
<s>
Other	O
common	O
Unix	B-Application
utilities	O
such	O
as	O
finger	O
were	O
re-written	O
to	O
make	O
them	O
network	O
aware	O
as	O
well	O
,	O
listing	O
all	O
of	O
the	O
people	O
logged	O
on	O
across	O
the	O
network	O
.	O
</s>
<s>
This	O
makes	O
a	O
Sprite	B-Operating_System
network	O
appear	O
as	O
if	O
it	O
were	O
a	O
single	O
large	O
time-sharing	B-General_Concept
system	I-General_Concept
,	O
or	O
a	O
single-system	B-Operating_System
image	I-Operating_System
.	O
</s>
<s>
Another	O
key	O
addition	O
to	O
Sprite	B-Operating_System
is	O
process	B-Operating_System
migration	I-Operating_System
,	O
which	O
allows	O
programs	O
to	O
be	O
moved	O
between	O
machines	O
at	O
any	O
time	O
.	O
</s>
<s>
Long	O
tasks	O
(	O
like	O
compiling	B-Language
the	O
Sprite	B-Operating_System
system	O
)	O
can	O
appear	O
very	O
fast	O
.	O
</s>
<s>
Work	O
on	O
the	O
"	O
early	O
"	O
Sprite	B-Operating_System
outlined	O
above	O
ended	O
around	O
1987	O
,	O
but	O
was	O
improved	O
during	O
the	O
next	O
year	O
.	O
</s>
<s>
Starting	O
in	O
1990	O
Sprite	B-Operating_System
was	O
used	O
as	O
the	O
basis	O
for	O
development	O
of	O
the	O
first	O
log-structured	B-Application
file	I-Application
system	I-Application
(	O
LFS	O
)	O
,	O
development	O
of	O
which	O
continued	O
until	O
about	O
1992	O
.	O
</s>
<s>
Under	O
Sprite	B-Operating_System
,	O
this	O
tradeoff	O
is	O
particularly	O
useful	O
because	O
most	O
read	O
access	O
is	O
cached	O
anyway	O
—	O
that	O
is	O
,	O
Sprite	B-Operating_System
systems	O
typically	O
perform	O
fewer	O
reads	O
than	O
a	O
normal	O
Unix	B-Application
system	I-Application
.	O
</s>
<s>
Additional	O
experimentation	O
on	O
striped	B-Architecture
file	O
systems	O
,	O
both	O
striped	B-Architecture
across	O
different	O
machines	O
as	O
well	O
as	O
clusters	O
of	O
drives	O
,	O
continued	O
until	O
about	O
1994	O
.	O
</s>
<s>
Sprite	B-Operating_System
was	O
not	O
a	O
microkernel	B-Operating_System
system	O
,	O
and	O
suffers	O
the	O
same	O
sort	O
of	O
problems	O
as	O
other	O
Unixes	B-Application
in	O
terms	O
of	O
development	O
complexity	O
,	O
becoming	O
increasingly	O
difficult	O
to	O
develop	O
as	O
more	O
functionality	O
was	O
added	O
.	O
</s>
<s>
By	O
the	O
1990s	O
it	O
was	O
suffering	O
and	O
the	O
small	O
team	O
supporting	O
the	O
project	O
was	O
simply	O
not	O
able	O
to	O
keep	O
up	O
with	O
the	O
rapid	O
changes	O
in	O
Unix	B-Application
taking	O
place	O
during	O
this	O
time	O
.	O
</s>
