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From: parkern@jacobs.CS.ORST.EDU (Neil Parker)
Newsgroups: comp.sys.apple2
Subject: Re: Silly ProDOS 8 question...
Summary: Because...um...er...well...just because!
Message-ID: <1991May02.030042.4611@lynx.CS.ORST.EDU>
Date: 2 May 91 03:00:42 GMT
References: <9105010233.AA21470@carroll1.cc.edu>
Sender: @lynx.CS.ORST.EDU
Reply-To: parkern@jacobs.CS.ORST.EDU (Neil Parker)
Organization: The Universal Society for the Prevention of Reality
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Nntp-Posting-Host: jacobs.cs.orst.edu

In article <9105010233.AA21470@carroll1.cc.edu> acct069@CARROLL1.CC.EDU
(Ron) writes:
>When ProDOS 8 boots there's a spurt of noise from the speaker.  What is
>ProDOS doing to make it do this?  Sometimes the noise is more of a short
>chirp than a spurt, does this have any significance?  Doing a cold boot
>changes it from a chirp to a burst (the normal sound).

The reason ProDOS makes noise when it boots is simple.  There is a LDA
$C030 instruction at the beginning of the routine that clears the screen
and displays the intro message ("PRODOS 8 V1.x, COPYRIGHT...", etc.), and
another LDA $C030 instruction at the end of this routine.

I have no idea why those LDA $C030 instructions are there, nor do I have
any idea why the sound seems to vary.

               - Neil Parker
--
Neil Parker                 No cute ASCII art...no cute quote...no cute
parkern@jacobs.cs.orst.edu  disclaimer...no deposit, no return...
parker@corona.uoregon.edu   (This space intentionally left blank:           )