Path: utzoo!attcan!uunet!lll-winken!lll-lcc!ames!killer!davidg
From: davidg@killer.DALLAS.TX.US (David Guntner)
Newsgroups: comp.sys.amiga
Subject: Re: PPPppppplllleeeeeaaaasssseeee stop clicking
Message-ID: <6521@killer.DALLAS.TX.US>
Date: 22 Dec 88 05:50:44 GMT
References: <742@zehntel.UUCP>
Organization: The Unix(R) Connection, Dallas, Texas
Lines: 21

From article <742@zehntel.UUCP>, by donw@zehntel (Don White):
> 
>      Can anyone at Commodore tell us why (in detail) the drives click? I know
>   they are looking for disk insertion, but HOW are they doing it and why?
>   Don't all drives have some kind of hardware to tell you if a drive is
>   loaded?  Couldn't drives be kept at one known location (like track 0)
>   where you KNOW there should be SOME information? ANd just do reads with
>   no more head positioning?

From what I understand, what AmigaDOS is doing is moving the head of the drive
from track 0 to track 1 (and then back again).  This changes a status bit if a
disk is present, and AmigaDOS (or is it a KickStart function?) then knows that
a disk has been inserted.  There are a few programs that stop the clicking by
making the head move from track 0 to track -1.  Since there ISN'T a track -1,
nothing moves/clicks, but that status bit still gets updated....
                   --Dave

-- 
        David Guntner  UUCP: {ames, mit-eddie}!killer!davidg
                       INET: davidg@killer.DALLAS.TX.US
"...Different ship, but she's got the right name. Treat   --Admiral L. McCoy
 her like a lady, and she'll always bring you home."    "Encounter at Farpoint"