On 01/24/2017 12:00 AM, Chuck Guzis wrote:
On 01/23/2017 09:42 PM, Jon Elson wrote:
On 01/23/2017 07:45 PM, Jon Elson wrote:
This blog seems to indicate that there is NO 7074, but an emulator
running on 370 hardware.
http://nikhilism.com/post/2016/systems-we-love/
This makes a lot more sense, some of these microcode emulations were
still available of fairly late machines. Also, it probably would not
be real hard to write a decent emulator for the 7074 and run it on
modern hardware. Once you are using emulation, why not keep the host
hardware current?
Too bad the excerpts from the original talk are totally scrambled.
It wouldn't surprise me if the IBM S/370 isn't being emulated as well.
It wouldn't be the first time for "nested" emulation.
Is there a "recursive" emulator setup wherein one machine emulates
another one...where the final emulation is for the original hardware?
I have no idea, although VM/370 systems tended to have a LOT
of instances of OS'es and virtual machines running.
I wonder how late IBM still supported the 7074 microcode
emulation? And, of course, anybody could write a
software-level emulation for the 7074, in IBM or other
hardware. One reason maybe to not run simh on a PC is if
the data comes in on old mag tapes (gasp, maybe even 556 BPI
NRZI half-inch tapes)?
Jon
