I should have known that you (instructor of the current and previous
maintainer) would have the answer off the top ;-)
Therefore by your description it mys be set always but I guess it is a
DGD; however, I do want to know that it is now.
Oh, and now that Big Drive Technology has been annouced I should finally
send you the code for 48-bit, sorry about the delay.
Cheers,
Andre Hedrick
ASL Kernel Development
Linux ATA Development
-----------------------------------------------------------------------------
ASL, Inc. Toll free: 1-877-ASL-3535
1757 Houret Court Fax: 1-408-941-2071
Milpitas, CA 95035 Web: www.aslab.com
On Fri, 29 Jun 2001 [EMAIL PROTECTED] wrote:
> Andre Hedrick wrote:
>
> > That is a legacy bit from ATA-2 but it is one of those things you cannot
> > get rid of :-(
>
> in ANSI X3.279-1996, "AT Attachment Interface with Extensions (ATA-2)",
> Approved September 11, 1996 , control register bit 3-7 are reserved.
>
> However ANSI X3.221-1994, "AT Attachment Interface for Disk Drives",
> Approved May 12, 1994, bit3 is "1" and bits 4-7 are "x".
> No further explanation.
>
> How far back must we go, to get the sense ?
>
> > struct {
> > unsigned bit0 : 1;
> > unsigned nIEN : 1; /* device INTRQ to host */
> > unsigned SRST : 1; /* host soft reset bit */
> > unsigned bit3 : 1; /* ATA-2 thingy */
> > unsigned reserved456 : 3;
> > unsigned HOB : 1; /* 48-bit address ordering */
> > } control_t;
> >
> > once I add-in the real def of bit3 then I will not
> > need to look it up again.
>
> bit3: 0: drive has 1-8 heads
> 1: drive has more than 8 heads
>
> (From old MFM/RLL times. In ATA-1 bit3 is set to 1.
> See also
> http://www.win.tue.nl/~aeb/linux/hdtypes/hdtypes-2.html
> .)
>
> Andries
>
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