Path: utzoo!utgpu!watserv1!watmath!att!pacbell!pacbell.com!decwrl!sun-barr!olivea!orc!inews!iwarp.intel.com!psueea!parsely!agora!billsey
From: billsey@agora.uucp (Bill Seymour)
Newsgroups: comp.sys.amiga.hardware
Subject: Re: Quantum Hard Drives
Message-ID: <1990Sep10.231016.403@agora.uucp>
Date: 10 Sep 90 23:10:16 GMT
References: <4306@crash.cts.com>
Organization: Open Communication Forum
Lines: 37

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 isn't a Quantum phenomenon per se, it's an AmigaDOS thing. The
Filesystem write the file, then goes back later to update the disk BAM. The
pause between writing the file data and the BAM is what you're seeing. You're
right in saying it's not the Quantum flushing it's cache, but rather the Amiga
flushing *it's* cache. This time is greatly reduced under 2.0...
	The long wait on bootup after a reset before the DOS cache is flushed
is caused by the system having to re-validate the drive. Since that DOS cache
hadn't been written, the bitmap flag was still set as invalid.

:--LaMonte
:
:"The most original .sig file yet: a non-existant one."-me
:
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:INET: lkoop@pnet01.cts.com


-- 
     -Bill Seymour             ...tektronix!reed!percival!agora!billsey
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