AIX 4.1.[45], 4.2[.1], and 4.3[.123]
BSDI BSD/OS 2.1, 3.[01], and 4.[01] for Intel-based systems
DC/OSx 1.1 for Pyramid systems
DEC OSF/1, Digital UNIX, Tru64 UNIX 2.0, 3.2, 4.0, and 5.[01]
FreeBSD 2.1.[67], 2.2[.x], 3.[012345], 4.[01], and 5.0 for
Intel-based systems
HP-UX 9.01, 10.20, and 11.00
Linux 2.0.3[2346] and 2.[1234].x for Intel-based systems
NetBSD 1.[2345] for Alpha, Intel, and SPARC-based systems
NEXTSTEP 3.[13] for NEXTSTEP architectures
OpenBSD 2.[01234567] for Intel-based systems
OpenStep 4.x
Reliant UNIX 5.4[34] for Pyramid systems
SCO OpenServer Release 3.0 and 5.0.[02456] for Intel-based systems
SCO UnixWare 2.1.[123] and 7[[.0].1] for Intel-based systems
Sequent PTX 2.1.9, 4.2.[13], 4.[34], 4.4[.1246], and 4.5[.1] for Sequent systems
Solaris 2.5.1, 2.6, 7, 8 BETA, and 8 BETA-Refresh
SunOS 4.1.x
Ultrix 4.2