[temp t13] Re: way too quiet on this list!

[stephen . cumpson]

Dear T13,

The motion to remove the AV Feature Set from ATA6 as noted in the
minutes of the last T13 meeting did come as quite a surprise to us
working to get HDD's inside the mainstream Consumer Electronics devices.

Although the mass market has not developed yet for HDD's in CE devices
we are working on many projects with HDD's. In general we are
only asking the question of when HDD's are to be included in CE devices
and not if. I can assure you all that CE companies as a whole prefer to
produce and sell in large volumes, so there is potential.

For simple applications it is of course possible to get a working system
without the AV Feature Set, but our goal was to help shape the proprietary
solutions that were being developed within each HDD vendor, to provide
a good solution for CE companies for the longer term.

My personal summary: The market potential for HDD's in CE devices is
still expected to be very large.

Technically my colleagues and I feel that the AV Feature Set is a good
solution when it is accepted that both IT and AV data have to be
issued with timing constraints by using an AV Feature Set READ/WRITE
STREAM command. This necessitates changes in the host software
stack, of course, but the results are worth it.

Typically even on a modern PC it is unwise to open any significant application
whilst burning a CD or DVD, or streaming in your DV from your camcorder.
Imagine a PC on which CD's and DVD's could be written whilst in parallel
starting a web browser and not having to throw the failed disc away when
the buffers underflow. This is an improvement.

Mixing standard IT commands with AV Stream commands is
unacceptable, as any timing guarantees offered by the AV
commands may be invalidated by any standard IT command.

My personal summary: Use AV STREAM command for IT and AV data
and do not mix standard IT command with AV STREAM commands.

The error reporting for streaming commands, of course, needs serious
consideration, but I believe our technical input has been useful in this area.
I have personally submitted a document on Stream Error Reporting for
streaming commands and there has been no negative technical feedback.
I assume some of T13 followers have read it.

My personal opinion is that even though this is an optional feature set,
now is a good time to standardise it. In this way both hosts and HDD
vendors have something to work from, if they choose to. Commitment from
T13 may alleviate the current 'chicken and egg' feeling that is apparent
from some quarters.

A point that seems to have raised some debate is the AV Model and
the performance tables. From a hosts' perspective this is only a nice to have
which may be sacrificed if it jepardizes the complete AV Feature Set.
Key features of an AV Feature Set that cannot be sacrificed are guaranteed
command completion times, and time sliced error handling.

As a final point, I would like to confirm that the (CE) hosts are still serious
about using an AV Feature Set. The reason that there has been reduced
presence in the T13 commission was related plainly to the fact that the
AV Feature Set provides an excellent technical solution that we can use
under the condition that the implementation follows the spirit of the
standard.

Kind regards,

Stephen.
--
Dr. Stephen Cumpson, Senior Scientist,
Group Storage Technologies, Building  WY 1 45, (WY12),
Philips Research Labs., Prof. Holstlaan 4, 5656 AA Eindhoven, The Netherlands
Tel.: +31 40 274 2762  Fax: +31 40 274 4927
Email: mailto:[EMAIL PROTECTED]
Web: http://www.research.philips.com/