[ Thanks to Amy Newman for this link. ]
In the mid-1980s, most of the open system file systems
came as part of a standard Unix release from USL. A few vendors,
such as Cray and Amdahl, wrote their own file systems. These
vendors generally did so because the standard UNIX file did not
meet the requirements of the day. UFS on Solaris came from another
operating system, which was written in the 1960s, called Multics.That brings us to the late 1980s, and by this time, we had a
number of high-performance file systems from companies such as
Convex, MultiFlow and Thinking Machines. Everyone who had larger
systems had their own file system, and everyone was trying to
address many, if not all, of the same issues.