IBM 7074 and then some: "Systems we love" conference

[Jon Elson]

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