System V

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UNIX System V
developer AT&T
License (s) proprietary
Current  version 4.2 (1992)
ancestry UNIX  V7
↳ UNIX System III
↳ UNIX System V
Architecture (s) Alpha , x86 , MIPS , 68k
Others most-referenced UNIX

UNIX System V , short System V ( English " System Five " debate usually /ˌsɪs.təm faɪv / ; translated: "system five"), sometimes SysV from AT & T is an output of UNIX - operating system and was first in 1983 as successor published by System III . The System V Release 4.2 version has been available since 1992.

With UNIX System V a new init system was introduced, which bears the name SysVinit and is or was used in many other Unix-like operating systems.


Although System V also refers to a specific Unix derivative , it is now commonly used to refer to a whole class of Unix derivatives that descend from the AT&T UNIX line (as opposed to the BSD line). The actual technical differences between System V and BSD are becoming increasingly blurred, on the one hand, because each line adopts many innovations from the competing line, and on the other hand, due to the ever increasing degree of distribution of the more basic GNU auxiliary programs (especially the GNU coreutils ) instead of the BSD / System -V programs.


The biggest differences were originally (compared to the current situation, as of 2005):

  • Network communication: System V favored the Transport Layer Interface , BSD relies on network sockets .
    Situation today: sockets are predominant
  • System V knew runlevel , BSD did not; this also relates to the way in which daemons are started, for example .
    Situation today: a tie, there are still two camps
  • the interprocess communication interfaces were defined completely differently and followed completely different philosophies.
    The situation today: The easier-to-use System V interfaces are practically everywhere.
  • the management of process signals was slightly different; the smaller differences, however, had big effects.
    Situation today: agreement on the best synthesis
  • some functions of the C library were implemented differently or followed different traditions.
    Situation today: tendency towards System V, although this is now done by other bodies ( POSIX , ANSI , ISO ).
  • some important programs behaved differently with the same options.
    ps : Even today this program has different properties in the GNU version, depending on how the options are specified.
    Situation today: a tie, it is left to the preferences of the respective developer.
  • Program names and the paths to them differed, partly in a way that is no longer comprehensible
    today .
    Situation today: System V was more exemplary here.
  • The BSD file system behaves differently when inheriting the owner properties of higher-level directories than System V-type file systems, with BSD properties are automatically inherited, with System V newly created objects receive the default properties set by the user

Releases and derivatives

  • 1983 - System V
  • 1984 - SVR2 (System V Release  2, meaning 2nd major version )
  • 1987 - SVR3 ( SGI IRIX )
  • 1988 - SVR3.2 ( SCO OpenServer )
  • 1989 - SVR4: integrated some BSD components; by specifying a corresponding path, the programs of the respective variant can be executed
  • 1992 - SVR4.2
  • 1993 - SVR4.2MP (UnixWare 2, Sun Solaris )
  • 1997 - SVR5 (SCO UnixWare  7)

See also

Web links