More from the past.. old operation systems

There's an open source mainframe emulator called Hercules which runs on
linux and windows.  Besides the current hardware, it can emulate a 360 or
370.

Apparently not all IBM OSs were licensed.  The 360's MFT and MVT are public
domain and vintage 370 versions of VM and MVS are available for download.

I'd guess that all versions of S/36 SSP were licensed.
But does anyone know if the S/3 and S/34 OSs were licensed ?

I'm not sure if all CPF releases were licensed.  My AS/400 signon screen
says "Copyright 1980",  but since the S/38 was introduced prior to this, I
wonder if Release 1 was the exception.

Admittedly, even if an emulator were available, there's little practical
value in running an old OSs.  But it would be a novelty.


Keith