** This is the quasi-official and semi-temporary T13 email list server. **
Okay if this is the right (erm correct) way to write a taskfile, what is
the correct way to read it back?
Andre Hedrick
Linux ATA Development
On Thu, 24 May 2001, Hale Landis wrote:
> Date: Thu, 24 May 2001 10:37:04 -0600
> From: Hale Landis <[EMAIL PROTECTED]>
> Reply-To: [EMAIL PROTECTED]
> To: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
> Subject: [temp t13] Re: 48-bit LBA
>
> ** This is the quasi-official and semi-temporary T13 email list server. **
>
> Confused?
>
> The HOB bit is used only to read back the full 48-bit LBA. The
> HOB bit is not used when writing the LBA to the device. In fact
> the HOB bit is set to 0 by the device on any write to a Command
> Block register.
>
> So lets assume you are running on a stupid x86 with little endian
> byte ordering and you have the 48-bit LBA in some memory area
> (most likely stored in a 64-bit data area) like this:
>
> addr LBA
> offset bits
> ------ ----
> 0 7-0
> 1 15-8
> 2 23-16
> 3 31-24
> 4 39-32
> 5 47-40
> 6 not used
> 7 not used
>
> I assume the algorithm would look like this:
>
> if ( 48-bit_command )
> {
> write offset 3 to Sector Number (LBA 31-24);
> write offset 4 to Cylinder Low (LBA 39-32);
> write offset 5 to Cylinder High (LBA 47-40);
> }
> write offset 0 to Sector Number (LBA 7-0);
> write offset 1 to Cylinder Low (LBA 15-8);
> write offset 2 to Cylinder High (LBA 23-16);
> if ( 28-bit_command )
> {
> write 40H (LBA=1) OR'ed with bits 3-0 of offset 3
> to Drive/Head (LBA 27-24);
> }
>
> Did I get it right?
>
>
> *** Hale Landis *** [EMAIL PROTECTED] ***
> *** Niwot, CO USA *** www.ata-atapi.com ***
>
>
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