<s>
Monotone	B-Application
is	O
an	O
open	B-Application
source	I-Application
software	I-Application
tool	O
for	O
distributed	B-Protocol
revision	I-Protocol
control	I-Protocol
.	O
</s>
<s>
Monotone	B-Application
tracks	O
revisions	O
to	O
files	O
,	O
groups	O
sets	O
of	O
revisions	O
into	O
changesets	O
,	O
and	O
tracks	O
history	O
across	O
renames	O
.	O
</s>
<s>
Monotone	B-Application
is	O
designed	O
for	O
distributed	O
operation	O
,	O
and	O
makes	O
heavy	O
use	O
of	O
cryptographic	O
primitives	O
to	O
track	O
file	O
revisions	O
(	O
via	O
the	O
SHA-1	B-Algorithm
secure	B-Algorithm
hash	I-Algorithm
)	O
and	O
to	O
authenticate	O
user	O
actions	O
(	O
via	O
RSA	B-Architecture
cryptographic	O
signatures	O
)	O
.	O
</s>
<s>
Monotone	B-Application
version	O
0.26	O
introduced	O
major	O
changes	O
to	O
the	O
internal	O
database	O
structures	O
,	O
including	O
a	O
new	O
structure	O
known	O
by	O
Monotone	B-Application
developers	O
as	O
a	O
roster	O
.	O
</s>
<s>
Monotone	B-Application
databases	O
created	O
with	O
version	O
0.26	O
can	O
not	O
exchange	O
revisions	O
with	O
older	O
Monotone	B-Application
databases	O
.	O
</s>
<s>
The	O
new	O
netsync	O
protocol	O
is	O
incompatible	O
with	O
earlier	O
versions	O
of	O
Monotone	B-Application
.	O
</s>
<s>
In	O
April	O
2005	O
,	O
Monotone	B-Application
became	O
the	O
subject	O
of	O
increased	O
interest	O
in	O
the	O
FOSS	B-License
community	O
after	O
Linus	O
Torvalds	O
mentioned	O
it	O
as	O
a	O
possible	O
replacement	O
for	O
BitKeeper	B-Protocol
in	O
the	O
Linux	B-Application
development	O
process	O
.	O
</s>
<s>
In	O
a	O
post	O
on	O
the	O
Linux	B-Application
kernel	I-Application
mailing	I-Application
list	I-Application
,	O
Torvalds	O
praised	O
Monotone	B-Application
and	O
disparaged	O
Subversion	B-Application
(	O
and	O
by	O
extension	O
,	O
all	O
client-server	O
version-control	B-Architecture
systems	O
)	O
:	O
</s>
<s>
Instead	O
of	O
adopting	O
Monotone	B-Application
,	O
Torvalds	O
decided	O
to	O
write	O
his	O
own	O
SCM	B-Architecture
system	O
,	O
Git	B-Application
.	O
</s>
<s>
Git	B-Application
's	O
design	O
uses	O
some	O
ideas	O
from	O
Monotone	B-Application
,	O
but	O
the	O
two	O
projects	O
do	O
not	O
share	O
any	O
core	O
source	O
code	O
.	O
</s>
<s>
Git	B-Application
has	O
a	O
much	O
stronger	O
focus	O
on	O
high	O
performance	O
,	O
inspired	O
by	O
the	O
lengthy	O
history	O
and	O
demanding	O
distributed	O
modes	O
of	O
collaboration	O
used	O
by	O
Torvalds	O
and	O
the	O
other	O
Linux	B-Application
kernel	O
authors	O
.	O
</s>
<s>
Torvalds	O
later	O
commented	O
on	O
Monotone	B-Application
's	O
design	O
and	O
performance	O
:	O
</s>
<s>
A	O
key	O
issue	O
debated	O
was	O
whether	O
the	O
replacement	O
of	O
BitKeeper	B-Protocol
should	O
support	O
cherry	O
picking	O
,	O
whereby	O
a	O
tree	O
maintainer	O
can	O
approve	O
a	O
subset	O
of	O
patches	O
while	O
rejecting	O
others	O
on	O
an	O
individual	O
basis	O
.	O
</s>
<s>
Torvalds	O
argued	O
that	O
this	O
approach	O
"	O
results	O
in	O
the	O
wrong	O
dynamics	O
and	O
psychology	O
in	O
the	O
system	O
"	O
by	O
shifting	O
burden	O
to	O
the	O
upstream	B-General_Concept
maintainers	O
rather	O
than	O
forcing	O
downstream	O
maintainers	O
to	O
put	O
more	O
effort	O
into	O
keeping	O
their	O
trees	O
free	O
from	O
garbage	O
.	O
</s>
<s>
He	O
further	O
argued	O
that	O
Monotone	B-Application
is	O
correct	O
in	O
its	O
aversion	O
to	O
cherry-picking	O
as	O
a	O
feature	O
,	O
but	O
then	O
failed	O
to	O
take	O
it	O
far	O
enough	O
by	O
not	O
making	O
it	O
easy	O
enough	O
to	O
"	O
throw	O
away	O
"	O
unclean	O
working	O
trees	O
after	O
their	O
purpose	O
is	O
served	O
.	O
</s>
<s>
Torvalds	O
also	O
noted	O
his	O
perception	O
that	O
Monotone	B-Application
at	O
that	O
time	O
had	O
not	O
achieved	O
the	O
performance	O
level	O
required	O
by	O
a	O
project	O
as	O
large	O
as	O
Linux	B-Application
kernel	O
development	O
.	O
</s>
<s>
Like	O
GNU	B-Protocol
arch	I-Protocol
,	O
and	O
unlike	O
Subversion	B-Application
,	O
Monotone	B-Application
takes	O
a	O
distributed	O
approach	O
to	O
version	B-Architecture
control	I-Architecture
.	O
</s>
<s>
Monotone	B-Application
uses	O
SHA-1	B-Algorithm
hashes	I-Algorithm
to	O
identify	O
specific	O
files	O
or	O
groups	O
of	O
files	O
,	O
as	O
with	O
Git	B-Application
and	O
Mercurial	B-Protocol
,	O
in	O
place	O
of	O
linear	O
revision	B-Architecture
numbers	I-Architecture
.	O
</s>
<s>
Each	O
participant	O
maintains	O
their	O
own	O
revision	O
history	O
,	O
stored	O
in	O
a	O
local	O
SQLite	B-Language
database	O
.	O
</s>
<s>
Prior	O
to	O
some	O
heavy	O
optimisation	O
in	O
revision	O
0.27	O
,	O
Monotone	B-Application
's	O
emphasis	O
on	O
correctness	O
over	O
optimisation	O
was	O
often	O
blamed	O
for	O
poor	O
initial	O
experiences	O
.	O
</s>
<s>
The	O
first	O
action	O
of	O
a	O
new	O
user	O
is	O
often	O
to	O
synchronize	O
(	O
clone	O
)	O
a	O
large	O
existing	O
Monotone	B-Application
database	O
,	O
an	O
action	O
which	O
often	O
took	O
hours	O
for	O
large	O
databases	O
,	O
due	O
to	O
the	O
extensive	O
validation	O
and	O
integrity	O
checking	O
which	O
Monotone	B-Application
performs	O
when	O
revisions	O
are	O
moved	O
through	O
the	O
network	O
.	O
</s>
<s>
Monotone	B-Application
is	O
especially	O
strong	O
in	O
its	O
support	O
for	O
a	O
diverge/merge	O
workflow	O
,	O
which	O
it	O
achieves	O
in	O
part	O
by	O
always	O
allowing	O
commit	O
before	O
merge	O
.	O
</s>
<s>
Although	O
Monotone	B-Application
originally	O
supported	O
a	O
variety	O
of	O
networking	O
protocols	O
for	O
synchronizing	O
trees	O
,	O
it	O
now	O
exclusively	O
uses	O
a	O
custom	O
protocol	O
called	O
netsync	O
,	O
which	O
is	O
more	O
robust	O
and	O
efficient	O
,	O
and	O
shares	O
some	O
conceptual	O
ground	O
with	O
rsync	B-Application
and	O
cvsup	O
.	O
</s>
<s>
Netsync	O
has	O
its	O
own	O
IANA-assigned	O
port	O
(	O
4691	O
)	O
and	O
older	O
versions	O
of	O
it	O
are	O
supported	O
by	O
a	O
Wireshark	B-Language
plug-in	O
for	O
traffic	O
analysis	O
.	O
</s>
<s>
There	O
is	O
no	O
separate	O
Monotone	B-Application
server	O
because	O
any	O
Monotone	B-Application
client	O
can	O
act	O
as	O
a	O
server	O
.	O
</s>
<s>
Other	O
features	O
of	O
Monotone	B-Application
include	O
:	O
</s>
<s>
Monotone	B-Application
can	O
import	O
CVS	B-Application
projects	O
.	O
</s>
<s>
,	O
possible	O
drawbacks	O
of	O
Monotone	B-Application
include	O
:	O
</s>
<s>
Monotone	B-Application
is	O
implemented	O
in	O
modern-dialect	O
C++	B-Language
on	O
top	O
of	O
the	O
Boost	B-Language
library	I-Language
,	O
the	O
Botan	B-Protocol
cryptography	O
library	O
,	O
and	O
the	O
SQLite	B-Language
database	O
library	O
.	O
</s>
<s>
Monotone	B-Application
supports	O
customization	O
and	O
extension	O
via	O
hook	O
functions	O
written	O
in	O
the	O
Lua	B-Language
programming	I-Language
language	I-Language
.	O
</s>
<s>
The	O
monotone	B-Application
build	O
process	O
is	O
automated	O
with	O
BuildBot	B-Application
and	O
includes	O
extensive	O
regression	O
tests	O
.	O
</s>
