<s>
The	O
Cyrus	B-Protocol
IMAP	I-Protocol
server	I-Protocol
is	O
electronic	O
mail	O
server	B-Application
software	I-Application
developed	O
by	O
Carnegie	O
Mellon	O
University	O
.	O
</s>
<s>
It	O
differs	O
from	O
other	O
Internet	B-Protocol
Message	I-Protocol
Access	I-Protocol
Protocol	I-Protocol
(	O
IMAP	B-Protocol
)	O
server	B-Application
implementations	O
in	O
that	O
it	O
is	O
generally	O
intended	O
to	O
be	O
run	O
on	O
sealed	B-Application
servers	I-Application
,	O
where	O
normal	O
users	O
cannot	O
log	O
in	O
.	O
</s>
<s>
The	O
mail	O
spool	O
uses	O
a	O
filesystem	O
layout	O
and	O
format	O
similar	O
to	O
the	O
Maildir	O
format	O
used	O
by	O
other	O
popular	O
email	O
servers	O
such	O
as	O
qmail	B-Application
,	O
Courier	B-Protocol
,	O
Dovecot	B-Language
,	O
etc	O
.	O
</s>
<s>
Users	O
can	O
access	O
mail	O
through	O
the	O
IMAP/IMAP	O
-S	O
,	O
POP3/POP3	O
-S	O
or	O
KPOP	O
protocols	O
.	O
</s>
<s>
The	O
Cyrus	B-Protocol
IMAP	I-Protocol
server	I-Protocol
supports	O
server-side	O
mail	O
filtering	O
through	O
the	O
implementation	O
of	O
a	O
mail	O
filtering	O
language	O
called	O
Sieve	O
.	O
</s>
<s>
The	O
private	O
mailbox	O
database	O
design	O
gives	O
the	O
server	B-Application
considerable	O
advantages	O
in	O
efficiency	B-General_Concept
,	O
scalability	B-Architecture
,	O
and	O
administratability	B-Application
.	O
</s>
<s>
The	O
server	B-Application
supports	O
access	O
control	O
lists	O
on	O
mailboxes	O
and	O
storage	O
quotas	O
on	O
mailbox	O
hierarchies	O
.	O
</s>
<s>
As	O
of	O
version	O
2.4.17	O
,	O
there	O
is	O
support	O
for	O
CalDAV	B-Protocol
and	O
CardDAV	B-Protocol
to	O
provide	O
an	O
integrated	O
calendaring	O
and	O
email	O
solution	O
,	O
and	O
also	O
support	O
for	O
viewing	O
email	O
via	O
an	O
RSS	B-Application
reader	I-Application
.	O
</s>
<s>
Prior	O
to	O
1994	O
,	O
Carnegie	O
Mellon	O
University	O
's	O
email	O
was	O
based	O
on	O
the	O
locally	O
developed	O
and	O
non-standard	O
Andrew	B-Operating_System
Messaging	I-Operating_System
System	I-Operating_System
(	O
AMS	O
)	O
-	O
written	O
in	O
the	O
early	O
1980s	O
as	O
part	O
of	O
the	O
Andrew	B-Operating_System
Project	I-Operating_System
.	O
</s>
<s>
This	O
was	O
very	O
advanced	O
for	O
its	O
day	O
,	O
but	O
had	O
major	O
scalability	B-Architecture
issues	O
and	O
Carnegie	O
Mellon	O
wanted	O
to	O
move	O
to	O
a	O
standards-compliant	O
mail	O
system	O
that	O
met	O
or	O
exceeded	O
the	O
feature	O
set	O
of	O
AMS	O
.	O
</s>
<s>
In	O
1994	O
the	O
Computing	O
Services	O
Division	O
at	O
Carnegie	O
Mellon	O
addressed	O
these	O
goals	O
by	O
starting	O
the	O
Cyrus	B-Protocol
Project	O
.	O
</s>
<s>
In	O
1998	O
,	O
Carnegie	O
Mellon	O
placed	O
all	O
of	O
its	O
incoming	O
freshmen	O
(	O
the	O
class	O
of	O
2002	O
)	O
on	O
the	O
Cyrus	B-Protocol
server	B-Application
for	O
the	O
first	O
time	O
and	O
in	O
December	O
2001	O
,	O
board	B-Application
access	O
(	O
which	O
had	O
been	O
mirrored	O
from	O
AMS	O
to	O
Cyrus	B-Protocol
)	O
,	O
was	O
cut	O
over	O
to	O
Cyrus	B-Protocol
completely	O
.	O
</s>
<s>
Several	O
members	O
of	O
the	O
Cyrus	B-Protocol
development	O
team	O
at	O
Carnegie	O
Mellon	O
went	O
on	O
to	O
become	O
leaders	O
in	O
the	O
development	O
of	O
large-scale	O
electronic	O
mail	O
infrastructure	O
elsewhere	O
:	O
John	O
Gardiner	O
Myers	O
was	O
Chief	O
Architect	O
of	O
Host	O
Mail	O
Infrastructure	O
at	O
America	O
Online	O
;	O
and	O
Rob	O
Siemborski	O
worked	O
on	O
Gmail	B-Application
infrastructure	O
at	O
Google	O
.	O
</s>
<s>
In	O
the	O
fall	O
of	O
2016	O
Carnegie	O
Mellon	O
announced	O
the	O
retirement	O
of	O
Cyrus	B-Protocol
IMAP	I-Protocol
as	O
their	O
electronic	O
mail	O
storage	O
service	O
,	O
with	O
Cyrus	B-Protocol
users	O
required	O
to	O
choose	O
between	O
on-campus	O
Microsoft	O
Exchange	O
and	O
Google	O
"	O
G	O
Suite	O
"	O
off-campus	O
mail	O
.	O
</s>
<s>
Cyrus	B-Protocol
is	O
still	O
being	O
actively	O
developed	O
.	O
</s>
