DMA/UDMA/?

[bg]

I have a gazillion questions, so I'll start off with this one -

In windows 98, origional (no updates) installation, what is the difference
between enabling DMA for a device in the control pannel and enabling UDMA
for a IDE device in the BIOS?

Is the control pannel DMA for the mother board DMA controller and the BIOS
UDMA allows the IDE drive to control DMA?


And this one -
Can anybody suggest some free software that will test my EDI buss for data
rates. Perhaps give me a report as to what level it supports and what levels
my drives support.

The bottom line to all of this, is that I have -
A UDMA-2 CDRW which causes lock ups if DMA is enabled in control pannel.
A UDMA-2 non writable CD drive that does not cause lock ups if DMA is
enabled in control pannel.
A UDMA-5 LBA, hard drive drive that causes very intermittant boot lock ups
A UDMA-2 LBA, hard drive that works excellent.

I can work around the lock up problems by disabling DMA in control pannel,
but I'd like to see how my
data rates are doing.
TIA bg

 

[Piers James]

for your hard disks get HD-Tach to test dtat rates.