Date: Thu, 21 Aug 2003 15:04:48 -0400 From: "Kurt J. Lidl" <lidl@pix.net> To: freebsd-hackers@freebsd.org Subject: Re: dd to floppies broken? Message-ID: <20030821150448.A15808@pix.net> In-Reply-To: <20030821183944.GA87316@ussenterprise.ufp.org>; from bicknell@ufp.org on Thu, Aug 21, 2003 at 02:39:44PM -0400 References: <20030821183421.GN85538@numachi.com> <20030821183944.GA87316@ussenterprise.ufp.org>
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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
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