This message is from the T13 list server.
Fixing the bytes/LBA at 512 is not acceptable.
In ATA/ATAPI-7, T13 established support for
* long LBAs
* multiple LBAs/physical sector
* multiple physical sectors/LBA
Thank You !!!
-----------------------------------------------------------------
Jim Hatfield
ATA Interface Firmware & T13 (ATA/ATAPI) Standards Representative
Seagate Technology - PSG
e-mail: [EMAIL PROTECTED]
s-mail: 389 Disc Drive; Longmont, CO 80503 USA
voice: 720-684-2120
fax : 720-684-2711
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|---------+---------------------------->
| | Jeff Garzik |
| | <[EMAIL PROTECTED]|
| | m> |
| | Sent by: |
| | [EMAIL PROTECTED]|
| | rg |
| | No Phone Info |
| | Available |
| | |
| | 06/07/2004 09:24 |
| | AM |
| | |
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>--------------------------------------------------------------------------------------------------------------|
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| To: Joerg Schilling <[EMAIL PROTECTED]>
|
| cc: [EMAIL PROTECTED], [EMAIL PROTECTED], [EMAIL PROTECTED]
|
| Subject: Re: [t13] 04-136r0.pdf SCSI to ATA Command Translations
|
>--------------------------------------------------------------------------------------------------------------|
This message is from the T13 list server.
Joerg Schilling wrote:
>>From [EMAIL PROTECTED] Fri Jun 4 21:14:23 2004
>
>
>>>>3.2 Read Capacity (10) Command (25h)
>>>>() BLOCK LENGTH IN BYTES
>>>>This value is currently set to 512 bytes,
>>>>which is the standard sector size for disk drives.
>>>
>>>
>>>I see us taking the chance to try to fix the bytes/LBA at 0.5 Ki, like
>>>MMC fixed the bytes/LBA at 2 Ki, shutting out the (empty set of?) ATA MO
>>>folk.
>>>
>>>I like that.
>
>
>>It shut out nobody.
>
>
>>IMO the OS request block size _should_ be constant at 512 octets. It
>>makes calculations easier, and representations more normal.
>
>
> Please do not forget CD/DVD writers.
>
> They use 2048 Bytes per block.
That's fine, it's a multiple of 512.
It's rather nice when the kernel block or filesystem driver can simply
store a shift count, and then do
BASE_SECTOR_SHIFT=9
dvd_wr_sector_shift=2
device_sector_shift=BASE_SECTOR_SHIFT + dvd_wr_sector_shift
block_bytes = (1 << device_sector_shift)
Storing things as a power-of-2 is very efficient on a number of host
platforms. And basing things off of a fixed base -- 9 (512 bytes) --
makes life even easier.
Jeff
