Subject: Re: DEV_B_SIZE
To: Steve Byan <>
From: None <>
List: tech-kern
Date: 01/31/2003 20:23:52
In message <>, Steve Byan writes

>> Not broken any worse than because of write-caching.
>Agreed, but IDEMA is proposing to do this to SCSI drives, too.

We've seen broken caching on SCSI as well, but not recently I think :-)

>But if someone were to plug a new 4K-block disk into a system compiled 
>to use 512 byte block disks, and the SCSI interface were faked to make 
>it appear that the disk could read and write 512-byte blocks, then what 
>happens? IDEMA's notion is that faking 512-byte logical size is good 
>enough to get new disks to work in systems running legacy code. My fear 
>is that it is not so simple.

If plug a 4k sector disk into a system which doesn't know how to find
out that the drive really is 4k sectors, then you will increase the
window for lossage.

>> The thing we really need is working tagged-queing...
>Since I believe tagged-queuing works in SCSI, I assume you are asking 
>for it in ATA? Or is there some feature missing from SCSI 
>tagged-queuing that you'd like to see?

Yes, I was talking ATA there.

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