SCO should give it a rest.
I have used their products extensively in my IT career. They SUCK! The only thing worse than SCO products has to be BSD.
SCO UnixWare caused me so many headaches in my IT career. I'm still dealing with that garbage in several sites. Slowly, I'm replacing everything with pSeries running AIX.
I have a couple of processes I can run under either RH9 Linux or Cygwin.
They all run better under Cygwin. Something to do with how it handles threads, I think.