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

[Jan-Erik Soderholm]

Simon Clubley wrote 2012-03-26 22:19:
> On 2012-03-26, JF Mezei<jfmezei.spamnot at vaxination.ca>  wrote:
>> John Wallace wrote:
>>
>>> Oh dear, not that silliness again. Not running Windows may be better
>>> than running Windows, but running a Linux layer underneath the
>>> emulator doesn't make it a "bare metal" emulator.
>>
>> Not sure how much of linux is included in that vtAlpha "bare bones". But
>> it is quite possible to really have a bare metal linux and this is
>> commonly done for embedded systems, TVs, thermostats, TV decoders etc.
>>
>
> In the embedded world, bare metal has a specific meaning. When your
> application is directly addressing the hardware it's running on
> without any operating system between the application and the hardware,
> the application is running in bare metal mode.
>
> When your application is talking to the hardware via a operating system
> supplied API, that is not bare metal mode.
>
> One specific example: one of the boards in front of me is a Atmel SAM7S256
> board (this one: http://olimex.com/dev/sam7-h256.html in case you are
> interested.) When my application directly talks to the hardware registers
> on this board and handles the interrupts directly, then it's running in
> bare metal mode.
>
> If I write a BSP for a RTOS and modify the same application to run on this
> board under that RTOS, then the application is no longer running in bare
> metal mode.
>
> If there's a cut down Linux between your application and the hardware,
> then that application is not running in bare metal mode. :-)
>

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 ?

The customer buys something called "vtAlpha" that can be runed on a
new "bare metal" box without installing anything else before. Fine.

In the same way, if someone buys your SAM7 "application" with a
builtin runtime version of a RTOS, he could get a "bare metal"
sam7-h256 board from Olimex and run it on.

The term "bare metal" is more how the user/customer looks at it.

If the user can install product "X" without pre-installing anything
else, product "X" runs on "bare metal". Doesn't matter a bit (to the
customer) what product "X" is built from.

Jan-Erik.









> Simon.
>