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Re: OS startup goals and steps

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"wolfgang kern" <nowhere@never.at> wrote in message 
news:mo8fov$vi5$2@speranza.aioe.org...
> James Harris wrote:

...

> Only the BIOS may know what's connected to the NMI-pin.

According to RBIL there are these standard-ish sources of information:

  port 0x0061 reports RAM or IO parity errors
  port 0x0461 (EISA) reports NMI status

And port 0x0462 (EISA) apparently allows software to trigger an NMI.

Of course, they may or may not be present on a given PC. And some 
chipsets have other sources of information about NMI.

...

>>> VESA-modelist, INT15_E820, EDID,

I've just looked up EDID. As I have complained about many other 
standards made up in this industry EDID is similarly awful. For example, 
depending on the version if you want to find out the display's 
resolution you can look at the following.

  Byte 38: x resolution
  Byte 39: aspect ratio (2 bits)

The x resolution is just one byte so is coded: You add 31 to it and 
multiply by 8 to get the real x resolution - and just hope it is really 
a multiple of 8.

The y resolution cannot be read. It must be estimated from the x 
resolution and one of the only four possible aspect ratios.

  https://en.wikipedia.org/wiki/Extended_Display_Identification_Data#Limitations

Nevertheless, despite EDID's limitations, where present it looks as 
though it should be able to detect if a new monitor has been added 
allowing the OS to adjust the display accordingly.

>> OK. Someone may (unwisely? or because the monitor has died) unplug 
>> one monitor and plug in another one while the OS is running but I 
>> guess the EDID info can be re-got as long as the OS notices.
>
> I'm not sure for monitors and graphic-cards survive hot-plug ?

IME they are OK. I have had enough monitor leads fall out in my time.

...

>>> One OS for different architectures ?
>
>> Yes. At least that's the plan....
>>
>>> I see an OS just as a link between hardware and human aka user-app. 
>>> :)
>
>> That's a valid view. I see the OS, however, as an environment for 
>> apps to run in. So the OS should provide the same services regardless 
>> of hardware. IMO a given app which is written for the OS should run 
>> on the OS irrespective of the machine it is running on. Just a 
>> different view.
>
> I agree with you view, but I think one OS flexible enough to cover 
> several different platforms will end up bloated.

No need for bloat. You can have multiple images built from the same and 
different sources. You don't have to have the code for all of them in 
one image. Each image can contain just what is needed for the target 
hardware.

James

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Thread

OS startup goals and steps "James Harris" <james.harris.1@gmail.com> - 2015-07-14 10:35 +0100
  Re: OS startup goals and steps "Rod Pemberton" <boo@fasdfrewar.cdm> - 2015-07-15 04:00 -0400
    Re: OS startup goals and steps "Rod Pemberton" <boo@fasdfrewar.cdm> - 2015-07-15 22:29 -0400
      Re: OS startup goals and steps "James Harris" <james.harris.1@gmail.com> - 2015-07-16 08:00 +0100
        Re: OS startup goals and steps "James Harris" <james.harris.1@gmail.com> - 2015-07-16 11:01 +0100
          Re: OS startup goals and steps "Rod Pemberton" <boo@fasdfrewar.cdm> - 2015-07-17 05:40 -0400
            Re: OS startup goals and steps "wolfgang kern" <nowhere@never.at> - 2015-07-17 17:58 +0200
        Re: OS startup goals and steps "Alexei A. Frounze" <alexfrunews@gmail.com> - 2015-07-16 03:24 -0700
  Re: OS startup goals and steps "James Harris" <james.harris.1@gmail.com> - 2015-07-16 10:32 +0100
    Re: OS startup goals and steps "wolfgang kern" <nowhere@never.at> - 2015-07-16 16:04 +0200
      Re: OS startup goals and steps "James Harris" <james.harris.1@gmail.com> - 2015-07-17 06:44 +0100
        Re: OS startup goals and steps "wolfgang kern" <nowhere@never.at> - 2015-07-17 17:50 +0200
    Re: OS startup goals and steps "Rod Pemberton" <boo@fasdfrewar.cdm> - 2015-07-17 06:10 -0400
      Re: OS startup goals and steps "James Harris" <james.harris.1@gmail.com> - 2015-07-17 18:07 +0100
        Re: OS startup goals and steps "Rod Pemberton" <boo@fasdfrewar.cdm> - 2015-07-18 03:35 -0400
  Re: OS startup goals and steps "wolfgang kern" <nowhere@never.at> - 2015-07-16 14:42 +0200
    Re: OS startup goals and steps "Rod Pemberton" <boo@fasdfrewar.cdm> - 2015-07-17 05:48 -0400
      Re: OS startup goals and steps "wolfgang kern" <nowhere@never.at> - 2015-07-17 17:29 +0200

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