Path: utzoo!attcan!uunet!cs.utexas.edu!bryan
From: bryan@cs.utexas.edu (Bryan Bayerdorffer @ Wit's End)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: 2 Amiga 3000 Questions (from a new Owner ;^))
Message-ID: <198@mohawk.cs.utexas.edu>
Date: 3 Jul 90 16:30:43 GMT
References: <1065@orange9.qtp.ufl.edu> <33215@ut-emx.UUCP>
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In article <33215@ut-emx.UUCP> lshaw@walt.cc.utexas.edu (logan shaw) writes:

	[about Quantum drives]
=-
=-After you have not used the disk for a period of 5 or 10 seconds, the
=-drive will decide to park itself.  Thus, you don't have to do it yourself.
=-Sometimes you'll see the little light flash when it does this.
=-
	Er, no.  The hard disk light flashes briefly after a short timeout
(which is more like 3 seconds) because the disk validator is accessing the
drive, updating the bitmap for some partition.  This is the Amiga system
software at work, not the drive controller.

=-Corollary:  If you reboot or power off within a few seconds of accessing the
=-disk, the head may not have had a chance to park, and bad things can happen.
=-Usually, you can appease the "Volume dh0: not validated" requestor by hitting
=-[retry] several times (be persistent).  If this happens, you'll see the hard
=-disk moving like you never thought it could, trying to figure out life.  The 
=-light will be on solid for a good 20 seconds or more.  Once it's done,
=-everything should be back to normal.
=-
	Quantum drives ALWAYS park when they lose power.  What happens when you
power down or reboot immediately after a disk access is that the disk validator
has not had a chance to update the bitmap.  When the Amiga subsequently boots,
the validator runs and discovers that the bitmap is invalid.  It then has to
read the entire directory tree to find out which sectors are in use.  This is
what all the disk activity is about.  If you cause a write to the disk during
this validation interval, you'll get the 'not validated' requestor.  Eventually
validation will terminate, and your retry will succeed.  None of this has
anything to do with parking the heads.  Think about it: what could possibly be
the reason for parking the heads on a warm reboot?