Szia,
amiről ez a Wikipedia cikk szól, az a régi POSIX subsystem, mely már nem használatos, ahogy a cikk jelzi is: "Starting with Windows XP, the POSIX subsystem is not included as part of standard Windows distributions and has been replaced by Interix."
A korábban SFU, mostanában SUA néven futó alrendszer kezel socketeket: "Supports pthreads, shared libraries, DSO's, job control, signals, sockets, shared memory", forrás: http://en.wikipedia.org/wiki/Interix
És nem service: "Interix is not an emulation of a Unix kernel, but rather an implementation of a user-mode subsystem running directly on top of the Windows NT kernel" forrás: http://en.wikipedia.org/wiki/Microsoft_Windows_Services_for_UNIX
Ajánlott olvasmány még: [url=http://technet.microsoft.com/en-us/library/cc754351(WS.10).aspx]Subsyst… for UNIX-based Applications and POSIX Compliance[/url], valamint a környéke.
Üdv,
mrceeka