Path: utzoo!attcan!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!bryan
From: bryan@cs.utexas.edu (Bryan Bayerdorffer @ Wit's End)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: Quantum Hard Drives
Message-ID: <217@mohawk.cs.utexas.edu>
Date: 8 Sep 90 16:55:46 GMT
References: <4306@crash.cts.com>
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In article <4306@crash.cts.com> lkoop@pnet01.cts.com (Lamonte Koop) writes:
=-I'm sorry if this has at one time been discussed, but I need some information
=-pertaining to Quantum HDs.  Specifically, I am curious about a particular
=-behavior of the drives after performing a write operation to the disk.  It
=-appears that after performing said write, the drive will perform another I/O
=-operation a second or so later, lasting just an instant.  (No, I'm not 
=-referring to the drive dumping it's cache buffer) Furthermore, if this 
=-operation is not performed, due to a system reset or such, no problems are
=-encountered with the drive, save for one peculiarity:  The drive will seem
=-to search for something for quite a while upon re-start, then apparently
=-having found it, will boot normally. (This seems to be a common behavior
=-to all Quantums I have encountered) What exactly is this small I/O operation
=-doing?  Thanks in advance.
=-

	This has nothing specifically to do with Quantum disks.  The disk
access after the short timeout is caused by the Amiga's disk validator process
revalidating the disk's bitmap after a write, and occurs with all hard disks,
and floppies, too, in fact.  If you reboot before the validator updates the
bitmap, then the disk validator has to read the entire file system structure
and rebuild the bitmap before allowing writes to the disk.