You might be right that it was not due the a.out format alone. Now I remember that at the same time there was some huge migration from libc5 to glibc! Maybe it

You might be right that it was not due the a.out format alone. Now I remember that at the same time there was some huge migration from libc5 to glibc! Maybe it was composition of libc5 + a.out + egcs that gave us speed(no swappng) back then. I might do some benchmark on "PCEM" emulator (only proper emulator for old hardware as it retains original speed of cpu, memory and hard drives) in my spare time.