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Date: Thu, 21 Aug 2003 15:04:48 -0400
From: "Kurt J. Lidl" <lidl@pix.net>
To: freebsd-hackers@freebsd.org
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	from bicknell@ufp.org on Thu, Aug 21, 2003 at 02:39:44PM -0400
Subject: Re: dd to floppies broken?
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On Thu, Aug 21, 2003 at 02:39:44PM -0400, Leo Bicknell wrote:
> fd0 is block buffered.  Try:
> 
> dd bs=18k of=/dev/rfd0c if=memtest86-2.9/precomp.bin
> 
> I forget why, but 18k maximizes performance on (some?) floppies.

Because a 1440 kbyte floppy has 80 tracks, and it's double sided.
Thus, 9kbyte per side, both sides get done at once == 18k per track.
So, you schedule a full track of data to be written at one go,
the head seeks, and you start the next transfer to the device.

-Kurt