<s>
The	O
Parallel	B-Application
Virtual	I-Application
File	I-Application
System	I-Application
(	O
PVFS	O
)	O
is	O
an	O
open-source	B-Application
parallel	B-Application
file	I-Application
system	I-Application
.	O
</s>
<s>
A	O
parallel	B-Application
file	I-Application
system	I-Application
is	O
a	O
type	O
of	O
distributed	B-Protocol
file	I-Protocol
system	I-Protocol
that	O
distributes	O
file	O
data	O
across	O
multiple	O
servers	O
and	O
provides	O
for	O
concurrent	O
access	O
by	O
multiple	O
tasks	O
of	O
a	O
parallel	O
application	O
.	O
</s>
<s>
PVFS	O
was	O
designed	O
for	O
use	O
in	O
large	O
scale	O
cluster	B-Architecture
computing	I-Architecture
.	O
</s>
<s>
A	O
Linux	B-Operating_System
kernel	I-Operating_System
module	O
and	O
pvfs-client	O
process	O
allow	O
the	O
file	O
system	O
to	O
be	O
mounted	O
and	O
used	O
with	O
standard	O
utilities	O
.	O
</s>
<s>
The	O
client	O
library	O
provides	O
for	O
high	O
performance	O
access	O
via	O
the	O
message	B-Application
passing	I-Application
interface	I-Application
(	O
MPI	O
)	O
.	O
</s>
<s>
PVFS	O
is	O
being	O
jointly	O
developed	O
between	O
The	O
Parallel	O
Architecture	O
Research	O
Laboratory	O
at	O
Clemson	O
University	O
and	O
the	O
Mathematics	O
and	O
Computer	O
Science	O
Division	O
at	O
Argonne	O
National	O
Laboratory	O
,	O
and	O
the	O
Ohio	B-Architecture
Supercomputer	I-Architecture
Center	I-Architecture
.	O
</s>
<s>
PVFS	O
is	O
now	O
known	O
as	O
OrangeFS	B-Application
in	O
its	O
newest	O
development	O
branch	O
.	O
</s>
<s>
PVFS	O
was	O
first	O
developed	O
in	O
1993	O
by	O
Walt	O
Ligon	O
and	O
Eric	O
Blumer	O
as	O
a	O
parallel	B-Application
file	I-Application
system	I-Application
for	O
Parallel	B-Operating_System
Virtual	I-Operating_System
Machine	I-Operating_System
(	O
PVM	B-Operating_System
)	O
as	O
part	O
of	O
a	O
NASA	O
grant	O
to	O
study	O
the	O
I/O	O
patterns	O
of	O
parallel	O
programs	O
.	O
</s>
<s>
PVFS	O
version	O
0	O
was	O
based	O
on	O
Vesta	O
,	O
a	O
parallel	B-Application
file	I-Application
system	I-Application
developed	O
at	O
IBM	O
T	O
.	O
J	O
.	O
Watson	O
Research	O
Center	O
.	O
</s>
<s>
Starting	O
in	O
1994	O
Rob	O
Ross	O
re-wrote	O
PVFS	O
to	O
use	O
TCP/IP	B-Protocol
and	O
departed	O
from	O
many	O
of	O
the	O
original	O
Vesta	O
design	O
points	O
.	O
</s>
<s>
PVFS	O
version	O
1	O
was	O
targeted	O
to	O
a	O
cluster	O
of	O
DEC	O
Alpha	O
workstations	O
networked	O
using	O
switched	O
FDDI	B-Protocol
.	O
</s>
<s>
In	O
late	O
1994	O
Ligon	O
met	O
with	O
Thomas	O
Sterling	O
and	O
John	O
Dorband	O
at	O
Goddard	O
Space	O
Flight	O
Center	O
(	O
GSFC	O
)	O
and	O
discussed	O
their	O
plans	O
to	O
build	O
the	O
first	O
Beowulf	B-Operating_System
computer	O
.	O
</s>
<s>
It	O
was	O
agreed	O
that	O
PVFS	O
would	O
be	O
ported	O
to	O
Linux	B-Application
and	O
be	O
featured	O
on	O
the	O
new	O
machine	O
.	O
</s>
<s>
Ross	O
completed	O
his	O
PhD	O
in	O
2000	O
and	O
moved	O
to	O
Argonne	O
National	O
Laboratory	O
and	O
the	O
design	O
and	O
implementation	O
was	O
carried	O
out	O
by	O
Ligon	O
,	O
Carns	O
,	O
Dale	O
Witchurch	O
,	O
and	O
Harish	O
Ramachandran	O
at	O
Clemson	O
University	O
,	O
Ross	O
,	O
Neil	O
Miller	O
,	O
and	O
Rob	O
Latham	O
at	O
Argonne	O
National	O
Laboratory	O
,	O
and	O
Pete	O
Wyckoff	O
at	O
Ohio	B-Architecture
Supercomputer	I-Architecture
Center	I-Architecture
.	O
</s>
<s>
As	O
many	O
of	O
these	O
goals	O
conflicted	O
with	O
development	O
for	O
Blue	B-Operating_System
Gene	I-Operating_System
,	O
a	O
second	O
branch	O
of	O
the	O
CVS	O
source	O
tree	O
was	O
created	O
and	O
dubbed	O
"	O
Orange	O
"	O
and	O
the	O
original	O
branch	O
was	O
dubbed	O
"	O
Blue.	O
"	O
</s>
<s>
PVFS	O
and	O
OrangeFS	B-Application
track	O
each	O
other	O
very	O
closely	O
,	O
but	O
represent	O
two	O
different	O
groups	O
of	O
user	O
requirements	O
.	O
</s>
<s>
As	O
of	O
2011	O
OrangeFS	B-Application
is	O
the	O
main	O
development	O
line	O
.	O
</s>
<s>
The	O
object-based	O
design	O
has	O
become	O
typical	O
of	O
many	O
distributed	B-Protocol
file	I-Protocol
systems	I-Protocol
including	O
Lustre	B-Application
,	O
Panasas	O
,	O
and	O
pNFS	O
.	O
</s>
<s>
BMI	O
has	O
multiple	O
implementation	O
modules	O
for	O
a	O
number	O
of	O
different	O
networks	O
used	O
in	O
high	O
performance	O
computing	O
including	O
TCP/IP	B-Protocol
,	O
Myrinet	B-General_Concept
,	O
Infiniband	B-Architecture
,	O
and	O
Portals	B-Operating_System
.	O
</s>
<s>
Kernel	B-Operating_System
modifications	O
are	O
not	O
needed	O
.	O
</s>
<s>
There	O
is	O
an	O
optional	O
kernel	B-Operating_System
module	O
that	O
allows	O
a	O
PVFS	O
file	O
system	O
to	O
be	O
mounted	O
like	O
any	O
other	O
file	O
system	O
,	O
or	O
programs	O
can	O
link	O
directly	O
to	O
a	O
user	O
interface	O
such	O
as	O
MPI-IO	O
or	O
a	O
Posix-like	O
interface	O
.	O
</s>
<s>
It	O
has	O
similarities	O
with	O
the	O
Linux	B-Application
VFS	B-Application
,	O
this	O
making	O
it	O
easy	O
to	O
implement	O
as	O
a	O
mountable	O
file	O
system	O
,	O
but	O
is	O
equally	O
adaptable	O
to	O
user	O
level	O
interfaces	O
such	O
as	O
MPI-IO	O
or	O
Posix-like	O
interfaces	O
.	O
</s>
<s>
The	O
components	O
are	O
the	O
PVFS2-server	O
,	O
the	O
pvfslib	O
,	O
the	O
PVFS-client-core	O
,	O
and	O
the	O
PVFS	O
kernel	B-Operating_System
module	O
.	O
</s>
<s>
that	O
all	O
operate	O
directly	O
on	O
the	O
file	O
system	O
without	O
using	O
the	O
kernel	B-Operating_System
module	O
(	O
primarily	O
for	O
maintenance	O
and	O
testing	O
)	O
.	O
</s>
<s>
A	O
state	O
machine	O
consists	O
of	O
a	O
number	O
of	O
states	O
,	O
each	O
of	O
which	O
either	O
runs	O
a	O
C	B-Language
state	O
action	O
function	O
or	O
calls	O
a	O
nested	O
(	O
subroutine	O
)	O
state	O
machine	O
.	O
</s>
<s>
To	O
date	O
the	O
only	O
implementation	O
has	O
been	O
the	O
Trove-dbfs	O
implementation	O
that	O
stores	O
bytestreams	O
in	O
files	O
and	O
key/value	O
pairs	O
in	O
a	O
Berkeley	B-Language
DB	I-Language
database	O
.	O
</s>
