ATA offers quite a
few ways to perform WRITE LONG and READ LONG functionality.
1. ATA-3 defined
WRITE LONG (command codes 32h and 33h) and READ LONG
(command codes 22h
and 23h), including a note that "The committe is considering removing READ LONG
and WRITE LONG commands in a future ATA standard." The commands are
obsolete in ATA-4.
2. The SCT (SMART
Command Transport) technical report defines a way to implement WRITE LONG
and READ LONG commands through SMART log pages (supporting 48-bit
LBAs).
Command:
SMART READ LOG, SMART WRITE LOG, READ LOG EXT, or WRITE LOG
EXT
Log address: E0h
(Writes) or E1h (Reads)
SCT Function code:
0001h (Read Long) and 0002h (Write Long)
Those log addresses are marked "Reserved" in
ata7v1r4b.
3. Proposal
e02126, defining new WRITE WRONG EXT and READ WRONG EXT commands, has apparently
been resurrected.
Any
chance of converging on one method? If WRITE WRONG continues, then a SCSI
equivalent would be helpful for the SCSI-to-ATA Translation (SAT)
project.
Since these commands each address a single logical block, it's unclear
how well they will work with long physical
sectors, where the ECC bytes are shared by more than one logical
block.
--
Rob Elliott, [EMAIL PROTECTED]
Hewlett-Packard Industry Standard Server Storage Advanced Technology
https://ecardfile.com/id/RobElliott
Rob Elliott, [EMAIL PROTECTED]
Hewlett-Packard Industry Standard Server Storage Advanced Technology
https://ecardfile.com/id/RobElliott
