Date: Fri, 31 Jan 2003 16:06:43 -0500 From: Steve Byan <stephen_byan@maxtor.com> To: <jkirby@storagecraft.com> Cc: "'Julian Elischer'" <julian@elischer.org>, <phk@FreeBSD.ORG>, <freebsd-fs@FreeBSD.ORG>, <tech-kern@netbsd.org> Subject: Re: DEV_B_SIZE Message-ID: <E63D8B4F-355F-11D7-B26B-00306548867E@maxtor.com> In-Reply-To: <000601c2c962$c04aa2d0$0300a8c0@jkirbydesk>
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On Friday, January 31, 2003, at 02:55 PM, Jamey Kirby wrote: > Who will do the translation? > > Will there be a device driver that makes the 4K disk look like a 512 > byte disk? No. > If so, the device driver would have to pre-read the 4K, > modify the 512 byte section and re-write the entire 4K. This would kill > performance. Yes, it would. > If this will be handled in the drive, the same sort of logic must be > employed and surly there will be a performance problem; unless the > drive > will be able to write the 512 bytes without a pre-read. Yes, there surely would be a performance problem if the I/O has to wait for a read-modify-write. There may be proprietary techniques for hiding the cost. The assumption is that this is purely a backward-compatibility case, and the performance hit would motivate folks to update their software to recognize the new larger block size. Regards, -Steve -------- Steve Byan <stephen_byan@maxtor.com> Design Engineer Maxtor Corp. MS 1-3/E23 333 South Street Shrewsbury, MA 01545 (508) 770-3414 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message
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