Re: FYSOS: The Graphical User Interface

From	"wolfgang kern" <nowhere@never.at>
Newsgroups	alt.os.development
Subject	Re: FYSOS: The Graphical User Interface
Date	2016-08-25 14:43 +0200
Organization	KESYS-development
Message-ID	<npmp7f$1f9n$1@gioia.aioe.org> (permalink)
References	(14 earlier) <npjl0o$s2o$1@dont-email.me> <npjtl5$v8l$2@gioia.aioe.org> <npmeqp$lfe$1@dont-email.me> <npmi0l$12mr$1@gioia.aioe.org> <npmjmm$58b$1@dont-email.me>

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James Harris wrote:
...
>> What could have hooked INT10 before your OS boot ?
 
> If booted just by the BIOS and my own boot sector, only the graphics 
> card ROMs may have hooked the vector.

It's supposed to do so, otherwise we see only dark screens :)

> But it is hard to verify that that's how the OS was booted.

just check on the vector, if the seg-part is in the range of 
0xc000.. then you can be sure that this mean the video ROM. 
 
> Think about your own OS. Couldn't someone who understood its boot 
> process provide the initial boot conditions the OS needs or expects? 

NO, such attempt would need a very strange modified BIOS. 

> If so, then that person could also hook INT 0x10 and others before 
> starting your code.

I cannot think how this could be done, there is nothing between my 
OS and the BIOS.
 
>>> It's not that I expect gremlins. This is more about warrantability.
>>> E.g. once our OSes have control can they guarantee security? Handing
>>> off control to some other code which runs with full privilege is a way
>>> to lose that guarantee.

>> I think we can trust that VESA/VBE/VGA-BIOS only deal with its well
>> known hardware. The only annoying thing I encountered is that mode
>> change and also text-mode font setup functions return with the default
>> PIT setting (18.2Hz). Looks like VBIOS have to use the timer but wont
>> check on its setting upfront. Not a big deal to restore it to my 1mS
>> after any, anway rare used, INT10 or INT6D call (6D is just an alias).
 
> That would be very annoying!

it once was annoying, my workaround is a single call to my PIT-setup.  

> And potentially hard to find. Did you discover it when you stepped 
> through the code? Or did you one day notice that the timer had been 
> reset and need to hunt down what had caused it?

I found this out almost immediate, because my beep sound became awful 
long at low frequencies after INT10 calls.
Since known I set the PIT again as desired after all INT10 calls.

> In your case the BIOS code was not malicious, just stupid. But still the 
> cause of a problem to our OSes. All the more reason to emulate our way 
> through BIOS calls, if possible. ;-)

emulation with hw-function analysis ?  good luck on that one.
 
> QED?

I found it on several cards, old S3 and newer ATI too. 
can you check if your INT10 fall back to 18.2Hz PIT setting ?
__
wolfgang

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FYSOS: The Graphical User Interface "Benjamin David Lunt" <zfysz@fysnet.net> - 2016-07-08 11:52 -0700
  Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-16 11:00 +0200
    Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-16 11:14 +0100
      Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-16 19:07 +0200
        Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-16 19:42 +0100
          Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-16 21:32 +0200
            Re: FYSOS: The Graphical User Interface Rod Pemberton <NoHaveNotOne@zxdehrnyya.cam> - 2016-08-16 23:22 -0400
              Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-17 13:50 +0200
                Re: FYSOS: The Graphical User Interface Rod Pemberton <NoHaveNotOne@zxdehrnyya.cam> - 2016-08-18 01:41 -0400
                Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-18 10:47 +0200
            Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-17 08:45 +0100
              Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-17 13:57 +0200
                Re: FYSOS: The Graphical User Interface Rod Pemberton <NoHaveNotOne@zxdehrnyya.cam> - 2016-08-18 01:47 -0400
                Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-18 10:59 +0200
                Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-18 11:37 +0100
                Re: FYSOS: The Graphical User Interface Rod Pemberton <NoHaveNotOne@zxdehrnyya.cam> - 2016-08-18 17:38 -0400
                Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-19 10:03 +0100
                Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-19 22:34 +0200
                Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-22 17:43 +0100
                Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-22 19:04 +0200
    Re: FYSOS: The Graphical User Interface "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-16 04:18 -0700
      Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-16 12:25 +0100
        Re: FYSOS: The Graphical User Interface "Rick C. Hodgin" <rick.c.hodgin@gmail.com> - 2016-08-16 04:41 -0700
        Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-16 19:19 +0200
      Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-16 19:14 +0200
    Re: FYSOS: The Graphical User Interface "Benjamin David Lunt" <zfysz@fysnet.net> - 2016-08-16 19:24 -0700
      Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-17 12:26 +0200
        Re: FYSOS: The Graphical User Interface "Mike Gonta" <mikegonta@gmail.com> - 2016-08-17 10:42 -0400
          Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-18 01:16 +0200
            Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-18 12:17 +0100
              Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-18 19:23 +0200
                Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-19 17:29 +0100
                Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-19 22:55 +0200
                Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-22 17:18 +0100
                Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-22 19:23 +0200
                Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-23 11:46 +0100
                Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-23 23:44 +0200
                Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-24 08:29 +0100
                Re: FYSOS: The Graphical User Interface "Alexei A. Frounze" <alexfrunews@gmail.com> - 2016-08-24 02:39 -0700
                Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-24 17:43 +0100
                Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-24 11:25 +0200
                Re: FYSOS: The Graphical User Interface Rod Pemberton <NoHaveNotOne@zxdehrnyya.cam> - 2016-08-23 17:50 -0400
                Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-24 09:14 +0100
                Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-24 12:39 +0200
                Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-25 10:46 +0100
                Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-25 12:40 +0200
                Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-25 12:10 +0100
                Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-25 14:43 +0200
                Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-27 13:56 +0100
                Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-27 15:59 +0200
                Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-27 17:03 +0100
                Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-27 22:43 +0200
                Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-28 09:22 +0100
                Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-28 11:51 +0200
                Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-28 13:08 +0100
                Re: FYSOS: The Graphical User Interface Rod Pemberton <NoHaveNotOne@zxdehrnyya.cam> - 2016-08-27 19:12 -0400
                Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-28 10:41 +0200
                Re: FYSOS: The Graphical User Interface Rod Pemberton <NoHaveNotOne@zxdehrnyya.cam> - 2016-08-28 08:48 -0400
                Re: FYSOS: The Graphical User Interface Rod Pemberton <NoHaveNotOne@zxdehrnyya.cam> - 2016-08-27 19:12 -0400
                Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-28 10:16 +0100
                Re: FYSOS: The Graphical User Interface Rod Pemberton <NoHaveNotOne@zxdehrnyya.cam> - 2016-08-28 08:46 -0400
                Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-28 18:45 +0100
                Re: FYSOS: The Graphical User Interface Rod Pemberton <NoHaveNotOne@zxdehrnyya.cam> - 2016-08-28 17:51 -0400
                Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-29 07:55 +0100
                Re: FYSOS: The Graphical User Interface Rod Pemberton <NoHaveNotOne@zxdehrnyya.cam> - 2016-08-29 06:40 -0400
                Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-31 06:43 +0100
                Re: FYSOS: The Graphical User Interface Rod Pemberton <NoHaveNotOne@zxdehrnyya.cam> - 2016-08-24 07:00 -0400
                Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-25 11:37 +0100
                Re: FYSOS: The Graphical User Interface Rod Pemberton <NoHaveNotOne@zxdehrnyya.cam> - 2016-08-25 18:45 -0400
                Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-26 10:00 +0200
                Re: FYSOS: The Graphical User Interface Rod Pemberton <NoHaveNotOne@zxdehrnyya.cam> - 2016-08-26 16:16 -0400
                Re: FYSOS: The Graphical User Interface "wolfgang kern" <nowhere@never.at> - 2016-08-27 15:10 +0200
                Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-27 17:59 +0100
                Re: FYSOS: The Graphical User Interface Rod Pemberton <NoHaveNotOne@zxdehrnyya.cam> - 2016-08-27 19:11 -0400
                Re: FYSOS: The Graphical User Interface James Harris <james.harris.1@gmail.com> - 2016-08-28 10:56 +0100
                Re: FYSOS: The Graphical User Interface Rod Pemberton <NoHaveNotOne@zxdehrnyya.cam> - 2016-08-28 08:45 -0400
        Re: FYSOS: The Graphical User Interface "Benjamin David Lunt" <zfysz@fysnet.net> - 2016-08-17 20:12 -0700

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