Direct Attach Ad Hoc Meeting Minutes, 8/94

Gene Milligan Gene_Milligan at
Wed Aug 24 09:05:47 PDT 1994

Kurt Wrote:
>3) Does system SW expect a guaranteed relationship between a physical
>  device and an AL_PA (like SCSI parallel)?
 The system guarantee for SCSI parallel was not as guaranteed as it might seem.
In former times I think it staid the same as long as the access was through a
HBA of the same manufacturer. However the translation between the system drive
identification and the SCSI ID actually depends upon the order in which the HBA
scans the bus. Now with SCAM it is up to the host to have a ULP which provides
utility to unscramble the addresses assigned by SCAM. It may remain the same if
steps are taken to have that happen but it is not automagic.
 My assumption, but you system guys speak up, is that there has to be a
controlled way that the relationship can be maintained. I view this a little
different than guaranteed.
> In particular, Seagate emphasized that recovering cached
>data when Write Caching was implemented requires ACA.
 This reads, to me, like recovering cached data is required (which it is in
some applications) but I presume most systems will not have the ULP facilities
to accomplish this. Does the profile anticipate making the ULP required? If not
the recovery should remain optional. Having ACA required is another matter and
I support it being required.
Gene Milligan
Gene Milligan -- Gene_Milligan at
Seagate Technology   -   920 Disc Drive   -   Scotts Valley, CA 95066 USA
Main Phone 408-438-6550   -   Email Problems postmaster at
Technical Support: BBS 408-438-8771  Fax 408-438-8137  Voice 408-438-8222  

### OGATE Version 8 message trace and attachment information:
### MsgFileName: m:\mgate\outbound\182.MSG
### Org Date:    08-24-94 08:09:18 AM
### From:        Gene Milligan at SEAGATE
### To:          scsi @ @ internet
### Subject:     Re: Direct Attach Ad Hoc Meeting Minutes, 8/94
### Attachments: none

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