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From: jacc@midas.UUCP (Jac Colby)
Newsgroups: comp.sys.amiga
Subject: Re: Amiga Multi-tasking Overhead
Message-ID: <926@midas.UUCP>
Date: Sun, 14-Dec-86 16:41:01 EST
Article-I.D.: midas.926
Posted: Sun Dec 14 16:41:01 1986
Date-Received: Tue, 16-Dec-86 18:40:25 EST
References: <1986Dec2.102542.4658@utcs.uucp> <1085@cbmvax.cbmvax.cbm.UUCP> <1986Dec11.185731.13459@utcs.uucp>
Reply-To: jacc@midas.TEK.COM (Jac Colby)
Organization: Tektronix, Inc., Beaverton, OR.
Lines: 26

In article <1986Dec11.185731.13459@utcs.uucp> wagner@utcs.UUCP (Michael Wagner) writes:
>I'm getting more and more convinced that the problem is in the File systems
>and the trackdisk.devices.  I now have a copy of AMIGAMON20, and by turning
>it up to very fast, I'm able to see that the trackdisk.devices and the file
>systems are being dispatched regularly, even when there is no disk activity.

When I was trying to figure out how to add my own external disks,
I noticed that the select lines went active once every second if a
disk was not present in a drive.  When a disk is placed in a
drive, its presence is always detected within one second, and the
validator is run.  However, the select lines *continue* to be
pulsed, and at an even higher rate.  I presume that this is done
to check for disk removal.  The disk-removed signal is active low,
so detection of disk removal or insertion must be done by polling.
An obvious question, though, is why doesn't the trackdisk.device
just check for disk-removed prior to each disk access?

I would guess that the overhead would go down if no disks are
present when running benchmarks.


Jac Colby	- they disclaim me around here, too.
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