IDEMA Request to the T10 committee

Aloisi, Paul paul_aloisi at
Fri Sep 21 05:19:36 PDT 2001

* From the T10 Reflector (t10 at, posted by:
* "Aloisi, Paul" <paul_aloisi at>

Changing the block size from 512 to 4K needs to be reviewed in all the SCSI
documents for the clear statement to IDEMA. A reflector discussion before
the November CAP and SPI meetings is important to make sure everyone gives
it some thought ahead of time.

This is required for ECC expansion for the higher density recording

When this is implemented the drivers and operating systems are the main
obstacles. We will have to work in STA to communicate this to all the
effected parties. We may need to develop a driver-operating system profile
document to support the change.

Thank you,

-----Original Message-----
From: John Lohmeyer [mailto:lohmeyer at]
Sent: Thursday, September 20, 2001 10:48 AM
To: Aloisi, Paul
Cc: Penokie, George (IBM) (E-mail); Ralph O. Weber
Subject: Re: IDEMA Request to the T10 committee


Unless we have screwed up somewhere I don't know about, the 4k block size 
should work fine.  However, it is pretty clear the IDEMA people are looking 
for a stronger statement.  I think I would have been willing to make such a 
statement about SCSI-2, but there are so many SCSI standards now that no one

is familiar with every one of them. The best we can do is to involve more 
people looking for any known holes.  A reflector discussion might be best 
plus we should put this topic on the SPI and CAP agendas.

In any case, the strongest statement that we could make is that T10 has 
examined this question and to the best of our knowledge there are no issues 
supporting the 4k block in the various T10 standards.   If they want this 
statement to come from T10, we will need to pass a motion at our November

Do you want to ask this question on the T10 reflector or would you rather 
that I do it?


At 08:19 AM 9/20/2001, Aloisi, Paul wrote:
>John, George,
>I was invited to a meeting at DISKCON, and received a formal request for a
>statement from IDEMA. IDEMA is in the process of changing the block size
>from 512 to 4K, this is required for the higher density disk.
>They want a clear state that the SCSI standards will allow the change to 4K
>block size on all levels. They already have tested SCSI drives running the
>4K, but they want to make sure that it is not an issue for any level in the
>SCSI standards.
>The replay needs to go back to:
>  Dr. Ed Grochowski
>  IBM Almaden Research Center
>  650 Harry Road, K61/C2
>  San Jose, CA 95120
>Telephone: 408-927-2043
>FAX: 408-927-3520
>Email: grchwski at
>Thank you,
>Address, FAX and Phone numbers changed 23-July-2001
>Paul D. Aloisi                       Phone: 603-222-8687
>Texas Instruments                Mobile:603-930-4104
>50 Phillippe Cote St               FAX: 603-222-8700
>Manchester, NH 03101         email: paul_aloisi at
>                                            web site:

John Lohmeyer                  Email: lohmeyer at
LSI Logic Corp.                Voice: +1-719-533-7560
4420 ArrowsWest Dr.              Fax: +1-719-533-7183
Colo Spgs, CO 80907
* For T10 Reflector information, send a message with
* 'info t10' (no quotes) in the message body to majordomo at

More information about the T10 mailing list