[Info-vax] WHY IS VSI REQUIRING A HYPERVISOR FOR X86 OPENVMS?

David Wade g4ugm at dave.invalid
Mon Jan 4 14:51:26 EST 2021


On 04/01/2021 13:16, Simon Clubley wrote:
> On 2021-01-01, Scott Dorsey <kludge at panix.com> wrote:
>> In article <rsljns$1c1u$1 at gioia.aioe.org>, Snowshoe  <no at spam.please> wrote:
>>>
>>> Is there such a thing as an OS-less VM hypervisor? More specifically, a
>>> hypervisor which is its own OS in a way, you boot it directly (not
>>> booting Linux/Windoze then starting the hypervisor) and pretty much the
>>> only thing you can do once booted is starting virtual machines.
>>
>> Yes.  This is rather common actually.  VM/370 is of course the great
>> grandaddy.
>>
> 
> I would still regard VM/370 as being an OS, just one with an unusual and
> highly specific set of capabilities.

When IBM announced VM/370 they included two operation systems.

There is CP which is sometimes called VM and which is almost a pure 
Hypervisor. Its job is to provide virtual machines which look as much as 
possible as like real S/370's.

Then there is CMS which is what users normally IPL into their virtual 
machines. CMS is a very simple single user OS about as complex as MS DOS.

There is a shared spool that is usde for reading, printing and punching.

> 
>> But once you get to this you then start getting arguments about what really
>> constitutes and operating system.
> 
> Are MS-DOS or RT-11 operating systems ? I would say yes, because they
> provide services to the applications running on top of them. Likewise,
> I would say that VM/370 is still an OS because it provides services to
> the operating systems running on top of it.
> 

I would say VM is, in modern parlance a Hypervisor.

> Simon.
> 

Dave
G4UGM



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