I was waiting for Clem to weigh in on this, since I assume he knows more about it than I do.

 

I wasn’t paying much attention to Unix on 370, but my impression has always been that there were multiple 370 ports. The only ones that were completed, to my knowledge, were the ESS one and AIX/370. I don’t know of the ESS one being available outside of AT&T.

 

I don’t know anything about the compilers used, would assume they were PCC-based, even if provided by IBM.

 

In 1989, when I left IBM, there were certainly plenty of 370 people inside IBM that would have understood 370 channels. I would have thought that to still be true in 1991, even with the buyout packages that encouraged people to retire. (It wasn’t until Gerstner became CEO in April 1993 that IBM abandoned the “full employment” traditions.)

 

What Clem says about the smaller footprint of devices rings true. There were also likely customers that wanted to run AIX alongside other VMs, just as there were customers who wanted to run MVS alongside other VMs.

 

Charlie