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From: jb@rti-sel.UUCP (Jeff Bartlett)
Newsgroups: net.micro.apple
Subject: Re: Apple //e Interrupts
Message-ID: <943@rti-sel.UUCP>
Date: Tue, 29-Jul-86 22:51:50 EDT
Article-I.D.: rti-sel.943
Posted: Tue Jul 29 22:51:50 1986
Date-Received: Thu, 31-Jul-86 02:00:25 EDT
References: <283@ski.UUCP> <175@uvicctr.UUCP> <2245@brl-smoke.ARPA> <3184@utcsri.UUCP>
Organization: Research Triangle Institute, NC
Lines: 35

> In article <2245@brl-smoke.ARPA> gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>) writes:
> >I haven't seen mention of this, but interrupts during disk I/O
> >can corrupt your disk.  ProDOS supports interrupts but they're
> >inhibited during critical timing loops.  If you need interrupts
> >
> >I have to agree that the Apple ][ family is really not designed
> >for real-time, multitasking use.  There's no reason it shouldn't
> >have been, except they didn't think of it in the first place.
> 
> Oh yeah? Any idea how much cost was saved ( way back when ) by making the
> CPU work its tail off in disk I/O, rather than using an LSI disk controller
> chip ? ( Not to mention trimming everything from the drive, e.g door switch,
> index hole sensor, track zero sensor. TUKATUKATUKATUKATUKATUKA!!)
> 
> Greg Smith     University of Toronto      UUCP: ..utzoo!utcsri!greg

An Apple ][ with software disk control will beat a
   Radio Shack model II (w/controller) hands down in disk performance.

   * Faster track to track seek time.
   * Higher density.
   * Fast transfer times.

Also you can operate the disk spinning backward, or lay down spiral sectors.

Maybe they should include a 2nd CPU on-board to process IO.

(My grip is:
    "why didn't they tie the parallel keyboard input into the interupts",
'Can you say "POLL" boys and girls?, I thought you could.' )


Jeff Bartlett				mcnc!rti-sel!jb
Center for Digital Systems Research
Research Triangle Institute