[ale] boot parms ide=???

[Marvin Dickens]

On Wednesday 19 February 2003 10:10 am, Geoffrey wrote:
> I'm still trying to figure this one out.  Can't find much documentation
> on all this.  I've since removed the boot parm reference and it appears
> that using hdparm is sufficient to get the most bang out of my drives.

The way I understand it is that ATA drives currently support 4 modes of 
operation. They are:

PIO (0-4 submodes)
Single-word DMA (0-2 submodes)
Multi-word DMA (0-2 submodes)
Ultra DMA (0-7 submodes)

Therefore, using this information, you can use the hdparm utility to
configure the drive like so:

hdparm -X00 -> restore default PIO mode
 hdparm -X01 -> disable IORDY

PIO modes (Programmed IO) (disk mode (above) + 8)
 hdparm -X08 -> PIO 0
 hdparm -X09 -> PIO 1
 hdparm -X10 -> PIO 2
 hdparm -X11 -> PIO 3
 hdparm -X12 -> PIO 4

SDMA modes (Single-word DMA) (disk mode (above) + 16)
 hdparm -X16 -> SDMA 0
 hdparm -X17 -> SDMA 1
 hdparm -X18 -> SDMA 2

MDMA modes (Multi-word DMA) (disk mode (above) + 32)
 hdparm -X32 -> MDMA 0
 hdparm -X33 -> MDMA 1
 hdparm -X34 -> MDMA 2

UDMA modes (Ultra-DMA) (disk mode (abov) + 64)
 hdparm -X64 -> UDMA 0 (ATA16)
 hdparm -X65 -> UDMA 1 (ATA 25)
 hdparm -X66 -> UDMA 2 (ATA 33)
 hdparm -X67 -> UDMA 3 (ATA 44)
 hdparm -X68 -> UDMA 4 (ATA 66)
 hdparm -X69 -> UDMA 5 (ATA 100)

Here is an example of how you can use the above information on a
UDMA 4 drive:

Determine how fast your drive(s) are running. To do this run the
following command:

hdparm -Tt /dev/hda

Next, find out which settings are currently enabled:

hdparm -c -d /dev/hda

You'll be able to tell whether 32 bit dma is enabled, if multicount is used,
and unmasked irq's. A catchall command to enable some or all features that
you would wantis:

hdparm -c1 -m16 -d1 /dev/hda

This enables 32bit access and multisector reads. These items may already be
present in a compiled kernel. It depends on distro.

To push further do the following:

hdparm -c1 -u1 -m16 -d1 -X66 /dev/hda


This enables unmasked irq's and Ultradma mode 2. They should work well but
 may cause problems on older drives. The udma setting won't work on
 motherboards (eg) lacking a udma66 (or newer) controller. If these settings
 improve your system, you can add the above command(s) to /etc/rc.local to be
 active at bootup. You can also find out more about your ide chipset by
 exploring /proc/ide


I hope this helps.

Best

Marvin Dickens

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