Re: Bidirectional SCSI commands and iSCSI

["Jim Hafner/Almaden/IBM" <hafner@almaden.ibm.com>]

Folks,

I'm not advocating variable length headers here to support bi-d commands.
More to the point, I'm suggesting that the fixed length header change (NOW)
to accomodate the bi-directional SCSI commands. Better now while the draft
is still in flux than later after its finalized and more hardware gets
built.

BTW, I see two approaches:
1) one universal header with enough fields for both directions
2) one header for classical uni-d commands and an additional header for
bi-d commands (as FCP is proposing)

My vote would be for option (1).

Jim Hafner


Stephen Bailey <steph@cs.uchicago.edu>@ece.cmu.edu on 10-03-2000 07:12:46
AM

Sent by:  owner-ips@ece.cmu.edu


To:   ips@ece.cmu.edu
cc:
Subject:  Re: Bidirectional SCSI commands and iSCSI



> I think that software initiators will be widely used and they are far
> more efficient with fixed length headers for widely used operations.

In ST, fixed length headers were a design choice to permit hardware
acceleration.

Other than on very slow links, it's hard to argue with the performance
advantages of fixed length headers under any circumstances.

Steph