[Info-vax] [OT] Bare metal definition, was: Re: VMS port to x86

[Simon Clubley]

On 2012-03-27, Jan-Erik Soderholm <jan-erik.soderholm at telia.com> wrote:
> Johnny Billquist wrote 2012-03-27 17:23:
>> On 2012-03-27 16.23, Jan-Erik Soderholm wrote:
>>> Bob Koehler wrote 2012-03-27 17:49:
>>>> In article<jkqkjv$p1i$1 at news.albasani.net>, Jan-Erik
>>>> Soderholm<jan-erik.soderholm at telia.com> writes:
>>>>>
>>>>> But Linux runs on "bare metal". And if that part is builtin in whatever
>>>>> the developer calles "the product", then what ? Doesn't "the product"
>>>>> then
>>>>> run on "bare metal"? Yes, one component of "the product" is some parts
>>>>> usualy called "Linux", but so what ? Why should the customer/user care ?
>>>>
>>>> Because the Linux kernel can't handle some of the hard real-time
>>>> applications that the user might have.
>>>>
>>>
>>> But that is a completly different question.
>>> It has nothing to do with the "bare metall" discussion.
>>
>> I think it has a lot of relevance if your "bare metal" actually introduce a
>> non-deterministic middle layer to your emulation.
>>
>> The bare metal actually, by definition, do not have this property. So I
>> would expect something that runs on the bare metal to retain that property,
>> which to some is a very much wanted property. By falsely claiming that a
>> product is running on the bare metal, when it actually is running on top of
>> an operating system, they are in fact doing false marketing, and implicitly
>> claim properties of their system which they can not back up.
>>
>> "Bare metal" is not just a word... It *means* something.
>>
>> Johnny
>>
>
> Windows runs on "bare metal", still many would claim that Windows
> is non-deterministic.
>

You are missing the point. :-)

You don't get deterministic behaviour simply by running your software
on bare metal; your software has to be designed to have deterministic
behaviour. Running on bare metal is what allows you to maintain that
deterministic behaviour (in the absence of a dedicated RTOS).

In order to guarantee deterministic behaviour on a platform, you need
to make sure that everything about that platform behaves in a predictable
and deterministic manner.

It doesn't matter if your software, in it's native environment, is the
most predictable and deterministic software in the world if it's running
on top of a hidden OS layer which is non-deterministic.

Simon.

-- 
Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP
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