Editing UNIX System V (section)

=== SVR1 ===
System V, known inside Bell Labs as Unix 5.0, succeeded AT&T's previous commercial Unix called [[UNIX System III|System III]] in January, 1983.<ref name="levenez">{{cite web
| url         = http://www.levenez.com/unix/
| title       = Unix History (Unix Timeline)
| first       = Éric
| last        = Lévénez
| archive-url  = https://web.archive.org/web/20020802080343/http://www.levenez.com/unix/
| archive-date = 2002-08-02
| url-status    = live
| access-date  = 2010-12-29
}}</ref>
Unix 4.0 was never released externally, which would have been designated as System IV.<ref>{{cite book |title=Overview of the XENIX 286 Operating System |publisher=Intel Corporation |date= November 1984 |url=http://bitsavers.trailing-edge.com/pdf/intel/system3xx/xenix-286/174385-001_Overview_of_the_XENIX_286_Operating_System_Nov84.pdf |page=1.10 |quote=There was no System IV.}}</ref><ref>{{cite newsgroup
  | title = UNIX History
  | author = Dale Dejager
  | date = 1984-01-16
  | newsgroup = net.unix
  | url = http://groups.google.com/group/net.unix/msg/b80689d4b3bff13f?dmode=source
}}</ref><ref>{{cite book |title=Modern Operating Systems |last=Tanenbaum |first=Andrew S. |quote=Whatever happened to System IV is one of the great unsolved mysteries of computer science. |location=Upper Saddle River, NJ |publisher=Prentice Hall |edition=2nd |year=2001 |page=[https://archive.org/details/modernoperatings00tane/page/675 675] |isbn=0-13-031358-0 |url=https://archive.org/details/modernoperatings00tane/page/675 }}</ref>
This first release of System V (called System V.0, System V Release 1, or SVR1) was developed by AT&T's UNIX Support Group (USG) and based on the Bell Labs internal USG UNIX 5.0.

System V also included features such as the [[Vi (text editor)|vi]] editor and [[curses (programming library)|curses]] from 4.1 BSD, developed at the [[University of California, Berkeley]]; it also improved performance by adding buffer and [[inode]] caches. It also added support for [[inter-process communication]] using messages, [[semaphore (programming)|semaphore]]s, and [[shared memory (interprocess communication)|shared memory]], developed earlier for the Bell-internal [[CB UNIX]].<ref name="kerrisk">{{cite book |title=The Linux Programming Interface |last=Kerrisk |first=Michael |year=2010 |publisher=No Starch Press |page=921}}</ref>

SVR1 ran on [[Digital Equipment Corporation|DEC]] [[PDP-11]] and [[VAX]] [[minicomputer]]s.