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Re: operating systems design

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On 29/01/15 22:11, ruben safir wrote:
> I'm wondering if anyone has a background in operating system design.
> I'm taking a class is OS's and the text is
>
> OPERATING
> SYSTEM
> CONCEPTS
> ABRAHAM SILBERSCHATZ
> 9th edition, and it says something that is puzzling me
>
>
>
> "Interrupts are an important part of a computer architecture. Each
> computer design has its own interrupt mechanism, but several functions
> are common. The interrupt must transfer control to the appropriate
> interrupt service routine. The straightforward method for handling this
> transfer would be to invoke a generic routine to examine the interrupt
> information. The routine, in turn, would call the interrupt-specific
> handler. However, interrupts must be handled quickly"
>
> " Since only a predefined number of interrupts is possible, a table of
> pointers to interrupt routines can be used instead*** to provide the
> necessary speed. The interrupt routine is called indirectly through the
> table, with no intermediate routine needed. Generally, the table of
> pointers is stored in low memory (the first hundred or so locations).
> These locations hold the addresses of the interrupt service routines for
> the various devices. This array, or interrupt vector, of addresses is
> then indexed by a unique device number, given with the interrupt
> request, to provide the address of the interrupt service routine for
> the interrupting device. Operating systems as different as Windows and
> UNIX dispatch interrupts in this manner."
>
>
> ***  Instead of what?  Just because you have a table of pointers to
> routines doesn't change the need for a routine, a generic routine
> perhaps, from accessing that table.
>

I think what he means is that having a set of specific ISRs on a per 
hardware basis is preferable to having one ISR and polling all the 
hardware to find out which one did it, and then vectoring to ITS ISR

>
> Ruben
>


-- 
Everything you read in newspapers is absolutely true, except for the 
rare story of which you happen to have first-hand knowledge. – Erwin Knoll

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operating systems design ruben safir <ruben@mrbrklyn.com> - 2015-01-29 17:11 -0500
  Re: operating systems design Rich <rich@example.invalid> - 2015-01-29 22:29 +0000
    Re: operating systems design ruben safir <ruben@mrbrklyn.com> - 2015-01-30 08:19 -0500
      Re: operating systems design "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2015-01-30 09:01 -0500
      Re: operating systems design Robert Heller <heller@deepsoft.com> - 2015-01-30 08:07 -0600
        Re: operating systems design Jeroen Belleman <jeroen@nospam.please> - 2015-01-30 15:43 +0100
          Re: operating systems design Robert Heller <heller@deepsoft.com> - 2015-01-30 09:09 -0600
      Re: operating systems design Rich <rich@example.invalid> - 2015-01-30 15:21 +0000
        Re: operating systems design Robert Heller <heller@deepsoft.com> - 2015-01-30 11:27 -0600
          Re: operating systems design Rich <rich@example.invalid> - 2015-01-30 19:10 +0000
            Re: operating systems design Jean-David Beyer <jeandavid8@verizon.net> - 2015-02-02 08:29 -0500
              Re: operating systems design Rich <rich@example.invalid> - 2015-02-02 15:09 +0000
      Re: operating systems design The Natural Philosopher <tnp@invalid.invalid> - 2015-02-03 00:11 +0000
  Re: operating systems design Jeroen Belleman <jeroen@nospam.please> - 2015-01-30 09:28 +0100
  Re: operating systems design The Natural Philosopher <tnp@invalid.invalid> - 2015-02-03 00:08 +0000
    Re: operating systems design Charlie Gibbs <cgibbs@kltpzyxm.invalid> - 2015-02-03 20:52 +0000
      Re: operating systems design The Natural Philosopher <tnp@invalid.invalid> - 2015-02-03 21:06 +0000
      Re: operating systems design Rich <rich@example.invalid> - 2015-02-03 21:19 +0000

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