Ultra DMA and CD-ROM

[Guest]

Hello !

I have Plextor 12/10/32.
With some testing jumper this drive can work with UDMA 2; without jumper
UDMA is disabled, and drive using Multi-Word DMA 2 (16.6 Mb/sec).

I know that this is not possible to achieve so high rates with CD-ROM, but
when drive in 33.3 Mb/sec -> my PC CPU is loaded just 5% on 8x.
With 16.6 Mb/sec - 17% @8x.

So I put jumper and working with UDMA 2.

But sometimes when some poor media inserted in drive, windows xp see errors
and automatically reduce interface speed even to PIO.
In this case data rate go to 3-8 Mb/sec -> it's not problem in terms of speed.
But this is real problem in terms of CPU loading.
In "PIO Only" mode my CPU is 38% loaded @8x. So my PC start working slowly...

I tried to uninstall/reinstall secondary channel-> first time all is OK.
CD-Rom in UDMA 2 again, but if i put bad media again -> XP slow down
interface to PIO again. And after restarting XP don't want to returning back
to UDMA2, even to Multi-Word DMA.

Why it happens?

Maybe someone knows how to do, that XP after rebboting takes data from BIOS
normally and change settings in registry to Ultra DMA 2 again.

It's very difficult to edit registry everytime after BAD MEDIA CD-R or CD_RW.

I just want to find some key in registry that monitoring Cd-ROM erros and
reset channel to PIO, and I want turn off this key...

Can anyone help ?

With best regards, Alexandr.

 

[Wesley Vogel]

DMA Reverts to PIO
http://www.michna.com/kb/WxDMA.htm

 

[*Vanguard*]

Hello !

I have Plextor 12/10/32.
With some testing jumper this drive can work with UDMA 2; without
jumper
UDMA is disabled, and drive using Multi-Word DMA 2 (16.6 Mb/sec).

I know that this is not possible to achieve so high rates with
CD-ROM, but when drive in 33.3 Mb/sec -> my PC CPU is loaded just 5%
on 8x.
With 16.6 Mb/sec - 17% @8x.

So I put jumper and working with UDMA 2.

But sometimes when some poor media inserted in drive, windows xp see
errors and automatically reduce interface speed even to PIO.
In this case data rate go to 3-8 Mb/sec -> it's not problem in terms
of speed. But this is real problem in terms of CPU loading.
In "PIO Only" mode my CPU is 38% loaded @8x. So my PC start working
slowly...

I tried to uninstall/reinstall secondary channel-> first time all is
OK. CD-Rom in UDMA 2 again, but if i put bad media again -> XP slow
down interface to PIO again. And after restarting XP don't want to
returning back to UDMA2, even to Multi-Word DMA.

Why it happens?

Maybe someone knows how to do, that XP after rebboting takes data
from BIOS normally and change settings in registry to Ultra DMA 2
again.

It's very difficult to edit registry everytime after BAD MEDIA CD-R
or CD_RW.

I just want to find some key in registry that monitoring Cd-ROM erros
and reset channel to PIO, and I want turn off this key...

Can anyone help ?

With best regards, Alexandr.

Might be less frustrating and less time consuming to just spend the $14
to get a newer CD-ROM drive which may better read the damaged CD. Or
get a CD scratch repair kit (http://snipurl.com/8b1n) to clean the laser
lens, but for their price and if you only have one bad CD then you might
want to see how much it would cost just to get a replacement CD sent to
you from the software maker. If the problem is the CD has a cloudy spot
rather than being scratched, polishing it won't help and you'll need to
get a replacement disc.

Could be the CD is out of balance, especially if the label is a glue-on
label rather than painted. Does the CD-ROM drive make lots of vibrating
noise when the CD is spinning? Since the label is not likely removable,
you will need to get a replacement CD.