BUFE Bit

Henry Gabryjelski henrygab at exchange.microsoft.com
Thu Feb 8 10:01:56 PST 2001


* From the T10 Reflector (t10 at t10.org), posted by:
* "Henry Gabryjelski" <henrygab at Exchange.Microsoft.com>
*
Katata-san,

Requiring the host to set the BUFE bit in the mode page continues the
problematic use of mode pages.  I agree with Bill that the default
setting should be automatically enabled.  If this is not the case, then
the host will not get the benefits of this functionality.  Hosts should
*never* depend upon error conditions for proper completion of commands,
such as completion of writes -- this is a very poor design.  The MMC3
document supports an error-free model of working with the device.
Should you desire the host to know this information, please suggest a
method for it to retrieve such information using the GET_CONFIGURATION
command.

sincerely,
.




-----Original Message-----
From: keiji_katata at post.pioneer.co.jp
[mailto:keiji_katata at post.pioneer.co.jp]
Sent: Wednesday, February 07, 2001 9:19 PM
To: mtfuji5 at avc-pioneer.com
Cc: mmc at dt.wdc.com; T10 at t10.org; mtfuji5 at avc-pioneer.com
Subject: Re: BUFE Bit





Hello Bill,

I can not understand what you want.

You already know the problem that after write command issued, host need
to
send synchronized cache command to execute complete write on disc when
BUF
is enabled. I think we need not to talk about the reason because it is
drive implementation issue. Anyway, Host shall know the BUFE settiong.

And what is the function that shall be handled automatically by the
device?
What is your automatic behavior? It shall deferent with us. You want to
go
back before MMC1 period? If you have very good automatic behavior, you
must
make your proposal for the document. If you need not to change document,
you must not change our implementation. You can go your way.

Without any actual proposal and explanation by document, you must not
change the document only for your convenience.

Keiji Katata
PIONEER CORP.




reply to mtfuji5 at avc-pioneer.com

to:   mmc at dt.wdc.com, T10 at t10.org, mtfuji5 at avc-pioneer.com
cc:    (bcc: Keiji Katata/Pioneer)
subject:  BUFE Bit


MMC3 subject:
Recently, the BUFE bit (WRITE PARAMETERS MODE PAGE) has been extended to
include CD-R/RW.  There has been some concern raised by host software
people
that this may not work well.

In fact, we do not understand why this has value in the case of
DVD-R/RW.
Specifically, providing the host with the ability to switch this feature
on
and off may only provide the host with additional complexity and no real
value.

The value of BUFE as it applies to DVD is a subject for RMC/MMC4,
however,
let us first consider changes to CD.  Due to the widespread use of
CD-R/RW,
we should serve the existing platforms by not changing anything.  When a
device has the lossless linking capability with CD-R/RW, the control of
the
feature is best left with the drive to apply during long streamed
writing.

It is important to have this function handled automatically by the
device.
That insures the highest level of compatibility.  So, I wish to remove
the
use of BUFE for CD in MMC3.

Bill McFerrin



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