Subject: Re: DEV_B_SIZE
To: None <>
From: Steve Byan <>
List: tech-kern
Date: 01/31/2003 16:06:43
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?


> 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.

Steve Byan <>
Design Engineer
Maxtor Corp.
MS 1-3/E23
333 South Street
Shrewsbury, MA 01545
(508) 770-3414