[Info-vax] VMS port to x86

[JKB]

Le Thu, 31 May 2012 13:56:36 -0700 (PDT),
John Wallace <johnwallace4 at yahoo.co.uk> écrivait :
> On May 31, 9:28 pm, JKB <j... at koenigsberg.invalid> wrote:
>> Le 31 May 2012 09:35:17 -0500,
>> Bob Koehler <koeh... at eisner.nospam.encompasserve.org> écrivait :
>>
>> > In article <slrnjse7if.ul.... at rayleigh.systella.fr>, JKB <j... at koenigsberg.invalid> writes:
>>
>> >>        That's why VMS should not be ported on x86, but on top of a real
>> >>        microkernel. L4 is a good candidate as it is compact and simple. If
>> >>        you want to port your OS on another processor, you only has to port
>> >>        microkernel (and toolchain).
>>
>> >    Port VMS to the hardware and you get the behaviour of VMS.
>>
>> >    Rewrite the VMS kernel and APIs to sit on top of a micro-kernel and you
>> >    get some other behaviour, limitted by what the micro-kernel can do.
>>
>> >    There are a great many applications that won't care.  And some that
>> >    will.
>>
>>         And why ?
>>
>> --
>> Si votre demande me parvient sur carte perforée, je titiouaillerai très
>> volontiers une réponse...
>> =>http://grincheux.de-charybde-en-scylla.fr
>
> Because most user mode applications mostly don't (or at least
> shouldn't) care about the exact behaviours of the underlying OS? Such
> user mode stuff probably already works fine in one of the various
> readily available VAX or Alpha emulators, subject to the usual
> commercial considerations, so a DIY VMS is not necessarily of major
> interest. Not necessarily a bad idea, but not necessarily attractive
> to IT departments and end users who just want a way to run routine VMS
> applications.
>
> On the other hand, VMS would happily let you run complex kernel-mode
> and/or real-time stuff on the same box that was supporting interactive
> and batch users. It may not always have been a bright idea to do that,
> but it usually worked. Sometimes these things came to depend on
> behaviours that weren't formally documented but were predictable and
> reliable; sometimes that kind of dependency happened even without the
> interactive and batch users.
>
> If micro[kernel]VMS doesn't demonstrably have those same reliable and
> predictable behaviours, it is probably of no interest to this class of
> application. There may not be lots of people in this class, but if the
> rest of the users are happy with an emulator...

	I don't understand why you think that a microkernel couldn't offer
	all capabilities required by OpenVMS. Don't forget that DEC has
	ported VMS (kernel and some features) on Mach a long time ago.

	JKB

-- 
Si votre demande me parvient sur carte perforée, je titiouaillerai très
volontiers une réponse...
=> http://grincheux.de-charybde-en-scylla.fr