System V Interface Definition, as described in "The System V Interface
Definition, Fourth Edition".
.TP
-POSIX.1
+POSIX.1-1990
IEEE 1003.1-1990 part 1, aka ISO/IEC 9945-1:1990s, aka "IEEE Portable
Operating System Interface for Computing Environments", as elucidated
in Donald Lewine's "POSIX Programmer's Guide" (O'Reilly & Associates,
"Programming for the real world \- POSIX.4"
by Bill O. Gallmeister (O'Reilly & Associates, Inc. ISBN 1-56592-074-0).
.TP
+POSIX.1c
+IEEE Std 1003.1c-1995 describing the POSIX threads interfaces.
+.TP
+POSIX.1-1996
+A 1996 revision of POSIX.1 which incorporated POSIX.1b and POSIX.1c.
+.TP
SUS, SUSv2
Single Unix Specification.
(Developed by X/Open and The Open Group. See also
http://www.UNIX-systems.org/version2/ .)
.TP
+POSIX.1-2001, SUSv3
+The 2001 revision and consolidation of the POSIX.1 and SUS standards
+into a single document, conducted under the auspices of the Austin group
+(http://www.opengroup.org/austin/ .)
+The standard is available online at
+http://www.unix-systems.org/version3/ ,
+and the interfaces that it describes are also available in the Linux
+manual pages package under sections 1p and 3p (e.g., "man 3p open").
+The standard defines two levels of conformance:
+.IR "POSIX conformance" ,
+which is a baseline set of interfaces required of a conforming system;
+and
+.IR "XSI Conformance",
+which additionally mandates a set of interfaces
+(the "XSI extension") which are only optional for POSIX conformance.
+XSI-conformant systems can be branded
+.IR "UNIX 03" .
+Two Technical Corrigenda (minor fixes and improvements)
+of the original 2001 standard have occurred:
+TC1 in 2003, and TC2 in 2004.
+.TP
4.3BSD/4.4BSD
The 4.3 and 4.4 distributions of Berkeley Unix. 4.4BSD was
upward-compatible from 4.3.