[Info-vax] OT: news from the trenches (re: Solaris)

[glen herrmannsfeldt]

lists at openmailbox.org wrote:
> On Thu, 12 Mar 2015 15:47:18 -0400
> Stephen Hoffman via Info-vax <info-vax at rbnsn.com> wrote:
 
>> IBM has a very long history of emulating previous generations
 
> n the mainframe nothing has been emulated. Of course they pioneered
> virtualization but the whole point of S/360 was one architecture
> implemented on machines from large to extra large. You're suggesting
> something that is completely infeasible, has never been done once in over
> 50 years of production and you're suggesting it's a foregone conclusion.
> That is just unsupportable and wrong.

Most models of S/360 also supported one or two previous generation
machines, usually partially with special microcode and partially
with software emulation. That allowed them to sell one to someone
running an older machine as they slowly migrated up to S/360.

They were still supporting emulators in the early S/370 years,
such as the 370/165 supporting a 7094 emulator. To support the 36
bit floating point format of the 165, there was hardware 
(and microcode) to use that format, though only when the emulator
was active.

-- glen