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

[Stephen Hoffman]

On 2015-03-12 23:47:33 +0000, glen herrmannsfeldt said:

> 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.

Ayup.   IBM mainframe emulation goes back earlier than that, too.   IBM 
had 1401 series emulation that was available in some of the System/360 
boxes.  (I helped port some code off a then-still-running IBM 1620, as 
the owner didn't want to continue with the IBM gear.  Never tangled 
with an actual and running 1401, though.)  There's also the Hercules 
emulator, if you want to run your mainframe software on some other box. 
Or maybe use the z390 stuff, depending on what you're up to.

As for another approach, the Transitive folks were the source for 
Apple's Rosetta, a package which allowed for transparent application 
migration from PPC to Intel on OS X.  I'd tend to see something like 
that used and likely in conjunction with an operating system port, if 
IBM does decide to start migrating folks off their proprietary 
platforms.



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