I think the weirdest I encountered was Apollo Domain/OS. But SPP-UX was close as a microkernel with an HP-UX compatible personality on top.
But in some sense, every high-performance platform back then was an abomination. Whether it was the variant of AIX on an SP2, the weirdly unique Irix versions that seemed to exist in each Origin system at each national lab, or the painfully slow fork/exec on a Cray T3E frontend system when compiling apps.
But in some sense, every high-performance platform back then was an abomination. Whether it was the variant of AIX on an SP2, the weirdly unique Irix versions that seemed to exist in each Origin system at each national lab, or the painfully slow fork/exec on a Cray T3E frontend system when compiling apps.