This message is from the T13 list server.

Greetings Singh,

First off, being 48-bit capable is really not relevant.  If you're using a 28-bit 
command, what it's behavior to that command is all that matters.

Now for the conditions.  The max number of sectors for a 28-bit command is 268,435,456 
(0x10000000), so the LBA range may go from 0 through 0x0FFFFFFF.  If the drive has 
this maximum value, or greater, then the first command using max LBA with one sector 
requested (as you show) should run successfully since you're asking for the very last 
LBA.  The second command must fail since the last LBA requested goes over the limit.  
Sector count 10 is what must break this case.

Please note that either case will fail if the Identify words 61:60 are less than this 
limit.  If the drive is a 100GB drive then the described addresses will fail because 
you're going past the end of the drive.  So read ID-Drive words 61:60 and then you'll 
find why one works and the other fails.  Maybe the drive is a 200GB drive, but it 
could still fail the 28-bit command since the ID-Drive words 61:60 are less than the 
maximum allowable.  BTW, you could also have a drive that doesn't follow the rules.

Good luck, MKE.


-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of ATA User
Sent: Monday, August 30, 2004 4:14 PM
To: T13
Subject: [t13] Fwd: 28-bit / 48-bit question

This message is from the T13 list server.


I forgot to say,
both drives have 48-bit mode supported
and enabled.

Best regards,
  Singh

--- ATA User <[EMAIL PROTECTED]> wrote:

> Date: Mon, 30 Aug 2004 16:06:21 -0700 (PDT)
> From: ATA User <[EMAIL PROTECTED]>
> Subject: 28-bit / 48-bit question
> To: T13 <[EMAIL PROTECTED]>
> 
> Please to help me.
> I am having a disk drive in 28-bits mode and do not
> knowing what to
> expecting for some test cases.
> �
> I send 28-bit read dma commandd with
> ���� start lba= 0x0FFF FFFF� and sector count=1
> Should I get an error ? or should it succeed ?
> I have 2 drives and they act different from each
> others.
> �
> I send 28-bit read dma commandd with
> ���� start lba= 0x0FFF FFFE� and sector count=10
> Should I get an error ? or should it succeed ?
> I have 2 drives and they act different from each
> others.
> �
> Best regards,
> � Singh
> 
> 
> 
> 
> 
>               
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