IRIX 5.3
From TechPubs Wiki
IRIX 5.3 was released in November of 1994, the last of the IRIX 5.x series that began in March of 1993. IRIX 5.3 improved system stability and introduced many features of IRIX such as XFS (with the XFS release in 12/1994), ELF executables and more. It replaced IRIX 4.0, and maintains compatibility with IRIX 4.0 by and large.
