RE: [t13] DRQ data block definition

[Curtis Stevens]

Title: [t13] DRQ data block definition

Alexander               Also keep in mind that ATA/ATAPI-7 introduced the concept of non-512 byte sectors.  Also, the concept of DRQ data block now goes beyond the commands found in the definition…     ------------------------------------------------- Curtis E. Stevens 20511 Lake Forest Drive #C-214D Lake Forest, California 92630 Phone: 949-672-7933 Cell: 949-307-5050 E-Mail: [EMAIL PROTECTED] Ambition is a poor excuse for not having enough sense to be lazy. From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Mark Overby Sent: Tuesday, July 05, 2005 9:55 AM To: Alexander Krebs; forum@t13.org Subject: RE: [t13] DRQ data block definition   Because on serial ATA a data block may be more than 512 bytes. Also that definition is chock full of parallel specific terminology. All the information is there, it's just moved to specific areas. Those words in IDENTIFY DEVICE are still fully described.   From: [EMAIL PROTECTED] on behalf of Alexander Krebs Sent: Tue 7/5/2005 2:17 AM To: forum@t13.org 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.