IRIX 6.0 and 6.1
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IRIX 6.0 was introduced based on IRIX 5.2 code for the R8000 systems in late 1994. 6.0.1 was a point release with upgrades from 5.3, and 6.1 was a further refinement. Again, these were only designed for the R8000 systems, referred to as "Power" systems. 6.1 is notable for releasing XFS, the filesystem that replaced EFS.
Additional Information
IRIX 6.1 in particular released an experimental version of the N32 ABI, replacing the O32 which was originally designed around limitations of the R2000 CPU.
