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From: sirkm@ssyx.ucsc.edu (Greg Anderson)
Newsgroups: comp.sys.atari.st
Subject: Re: Non busy-wait disk IO on the ST.
Message-ID: <9042@saturn.ucsc.edu>
Date: 8 Sep 89 15:26:02 GMT
References: <9023@saturn.ucsc.edu> <1685@atari.UUCP>
Sender: usenet@saturn.ucsc.edu
Reply-To: sirkm@ssyx.ucsc.edu (Greg Anderson)
Organization: UC Santa Cruz; Division of Social Sciences
Lines: 53

In article <1685@atari.UUCP> apratt@atari.UUCP (Allan Pratt) writes:
> >I would like to be able to initiate disk IO in a program, go away
> >and do something else & then be informed later (via an interrupt)
> >that the opperation completed.
>
>You'll get no help from GEMDOS or the BIOS.

That's what I was afraid of.

>You can do it yourself,
>but you'll have to learn all about the DMA chip and any DMA devices you
>plan to talk to.

What is the best (actually, cheapest and easiest to obtain) documentation
on the DMA chip?  I've been surviving with the Laser C manual (which
is quite good, for the things it documents).

>The circuitry is all there: the acknowledge from the
>DMA device (which says the operation is complete) can cause an
>interrupt if you want, and that's really all you need.  (Of course, you
>have to deal with timeouts, etc...)

That doesn't bother me as much as rewriting GEMDOS.  I suppose I could
just create a blank partition on my hard drive and _only_ do direct
sector access, but there are some things that I'd really like to keep
in files.

I'm not really in the mood for writing a DOS, though, and I doubt
I could get GEMDOS source.  (Come to think of it, I'm not really in
the mood for rewriting a DOS either...)

>It's a lot of work, but there's nothing in hardware stopping you. It's
>possible that MINIX and/or OS/9 and/or some flavors of UNIX on the ST
>do this.  I don't know about that.

I should probably just buy a multitasking OS for the ST instead of
trying to write one myself.  (That's not literally what I'm doing,
but...)  Any recommendations from people who have used Minix &/or
OS/9?

>Anyway, good luck.

Looks like I'm going to need it.  Thanks for your comments.

>============================================
>Opinions expressed above do not necessarily	-- Allan Pratt, Atari Corp.
>reflect those of Atari Corp. or anyone else.	  ...ames!atari!apratt


  ___\    /___               Greg Anderson              ___\    /___ 
  \   \  /   /         Social Sciences Computing        \   \  /   /
   \  /\/\  /    University of California, Santa Cruz    \  /\/\  /
    \/    \/              sirkm@ssyx.ucsc.edu             \/    \/