* Re: FW: Fastest possible UDMA - how?
2003-01-10 19:04 ` FW: Fastest possible UDMA - how? Manish Lachwani
@ 2003-01-10 19:20 ` Valdis.Kletnieks
2003-01-10 19:27 ` Manish Lachwani
2003-01-10 20:15 ` Alan Cox
2003-01-10 20:48 ` Andre Hedrick
2 siblings, 1 reply; 7+ messages in thread
From: Valdis.Kletnieks @ 2003-01-10 19:20 UTC (permalink / raw)
To: Manish Lachwani; +Cc: linux-kernel, Michael.Knigge
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On Fri, 10 Jan 2003 11:04:03 PST, Manish Lachwani <m_lachwani@yahoo.com> said:
> Take a look at the drive IDENTIFY data. From the ATA
> spec, it can be seen that word# 88 in the IDENTIFY
> data can help you find out the UDMA mode selected and
> UDMA mode supported.
>
> The UDMA mode supported is the maximum supported by
> the drive.
Will this DTRT if the IDE *controller* does UDMA-5 but the drives are UDMA-2
at best?
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: FW: Fastest possible UDMA - how?
2003-01-10 19:20 ` Valdis.Kletnieks
@ 2003-01-10 19:27 ` Manish Lachwani
2003-01-10 20:09 ` Valdis.Kletnieks
0 siblings, 1 reply; 7+ messages in thread
From: Manish Lachwani @ 2003-01-10 19:27 UTC (permalink / raw)
To: Valdis.Kletnieks; +Cc: linux-kernel, Michael.Knigge
If the drives support UDMA 2, then the controller will
operate in UDMA 2. In that case, the IDENTIFY
information will show UDMA 2 for UDMA mode selected
and UDMA 2 for UDMA mode supported.
Now, say that I have a drive that supports UDMA 6 and
the controller supports UDMA 5. Then, from the
IDENTIFY information, the UDMA selected would be UDMA
5 while the UDMA supported would be UDMA 6.
Thanks
manish
--- Valdis.Kletnieks@vt.edu wrote:
> On Fri, 10 Jan 2003 11:04:03 PST, Manish Lachwani
> <m_lachwani@yahoo.com> said:
> > Take a look at the drive IDENTIFY data. From the
> ATA
> > spec, it can be seen that word# 88 in the IDENTIFY
> > data can help you find out the UDMA mode selected
> and
> > UDMA mode supported.
> >
> > The UDMA mode supported is the maximum supported
> by
> > the drive.
>
> Will this DTRT if the IDE *controller* does UDMA-5
> but the drives are UDMA-2
> at best?
>
> ATTACHMENT part 2 application/pgp-signature
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: FW: Fastest possible UDMA - how?
2003-01-10 19:04 ` FW: Fastest possible UDMA - how? Manish Lachwani
2003-01-10 19:20 ` Valdis.Kletnieks
@ 2003-01-10 20:15 ` Alan Cox
2003-01-10 19:31 ` Michael Knigge
2003-01-10 20:48 ` Andre Hedrick
2 siblings, 1 reply; 7+ messages in thread
From: Alan Cox @ 2003-01-10 20:15 UTC (permalink / raw)
To: Manish Lachwani; +Cc: Linux Kernel Mailing List, Michael.Knigge
On Fri, 2003-01-10 at 19:04, Manish Lachwani wrote:
> Take a look at the drive IDENTIFY data. From the ATA
> spec, it can be seen that word# 88 in the IDENTIFY
> data can help you find out the UDMA mode selected and
> UDMA mode supported.
>
> The UDMA mode supported is the maximum supported by
> the drive.
Not always true. There are a wide number of cases where the
UDMA mode being used is not the highest one the drive
or controller supports. The most simple example is if we
decide the cabling is not suitable for UDMA66 and higher.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: FW: Fastest possible UDMA - how?
2003-01-10 19:04 ` FW: Fastest possible UDMA - how? Manish Lachwani
2003-01-10 19:20 ` Valdis.Kletnieks
2003-01-10 20:15 ` Alan Cox
@ 2003-01-10 20:48 ` Andre Hedrick
2 siblings, 0 replies; 7+ messages in thread
From: Andre Hedrick @ 2003-01-10 20:48 UTC (permalink / raw)
To: Manish Lachwani, Manish Lachwani; +Cc: linux-kernel, Michael.Knigge
I guess if Google can publish their patches to the driver they ship,
Zambeel should consider publishing the known changes they ship with
products. Zambeel should decide if it is going to contribute or just
take.
Cheers,
Andre Hedrick
LAD Storage Consulting Group
On Fri, 10 Jan 2003, Manish Lachwani wrote:
> Take a look at the drive IDENTIFY data. From the ATA
> spec, it can be seen that word# 88 in the IDENTIFY
> data can help you find out the UDMA mode selected and
> UDMA mode supported.
>
> The UDMA mode supported is the maximum supported by
> the drive.
>
> Thanks
> Manish
>
> > Hi all,
> >
> > is it somehow possible to determine what is the
> > fastest UDMA-Mode my
> > IDE-Controller supports - independant of the
> > chipset?
> >
> > Thanks,
> > Michael
> >
> >
> >
> > -
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> > Please read the FAQ at http://www.tux.org/lkml/
> >
>
>
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^ permalink raw reply [flat|nested] 7+ messages in thread