From: [EMAIL PROTECTED] on behalf of Alexander Krebs
Sent: Tue 7/5/2005 2:17 AM
To: [email protected]
Subject: [t13] DRQ data block definition
This message is from the T13 list server.
Hi
all,
Does anybody know why the definition of the term "DRQ data
block"
changed from
ATA/ATAPI-7, vol 1, rev 3c
3.1.42 DRQ data
block: This term describes a unit of data words transferred during a single
assertion of DRQ when using PIO data transfer. A data block is transferred
between the host and the device as a complete unit. For all PIO data transfer
commands except READ MULTIPLE, WRITE MULTIPLE, and PACKET, a DRQ data block is
one sector, 512 bytes. For READ MULTIPLE and WRITE MULTIPLE commands the DRQ
data block is the number of sectors indicated in word 59 of the IDENTIFY DEVICE
response. For PACKET command the DRQ data block for transfer of the command
packet is the number of bytes indicated in word 0 of the IDENTIFY PACKET DEVICE
response.
to
ATA/ATAPI-7, vol 1, rev 3d
3.1.44 DRQ data block:
This term describes a unit of data words transferred during a single assertion
of DRQ when using PIO data transfer.
?
Given the lost sentences in
ATA/ATAPI-7, rev 3d, how shall host and
device determine the exact size of a
DRQ data block? Since both host
and device need to agree on the size of a DRQ
data block, this is an
essential definition. Did this information move
somewhere
else?
Thanks,
Alex.
