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OOOPS!

I forgot that many devices DO terminate bursts during longer data transfers
for improved CRC protection, though I would expect this to happen very
quickly in cases where data was in the device's buffer for a READ or space
was available in the device's buffer for a WRITE (terminate, check CRC,
initiate, all done at hardware speeds).

Regards,

Mark Evans
Maxtor Corporation
500 McCarthy Boulevard
Milpitas, CA 95035 USA
Tel:  408-894-5310

 -----Original Message-----
From:   Jim Castleberry [mailto:[EMAIL PROTECTED]] 
Sent:   Wednesday, November 28, 2001 8:53 AM
To:     Evans, Mark
Cc:     'Keith Clausen'; [EMAIL PROTECTED]
Subject:        Re: [t13] Command completion of an UDMA OUT burst ...

On Wed, Nov 28, 2001 at 07:48:18AM -0800, Evans, Mark wrote:
> In addition, I
> think that most HDDs won't initiate burst termination before all data for
a
> command is transferred.  So, if there is a burst termination, it's because
> the host wanted to do something else.

In the few dozen devices from various manufacturers that I've had a reason
to look at in the lab, I don't think I've ever seen one that did NOT
terminate the burst before all data was transferred (not counting commands
transferring 1 sector or less).  And I've never seen one do a UDMA Pause
either.  They all seem to terminate for flow control rather than Pause.
YMMV.

jcastle
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