ATA on hard drive

[MajBach1]

Me again! I have an older DFI MxBoard capable of ATA66 and a WD JB80 Gig
Caviar HD. On the same cable is aCd-Writer and on the secondary is a Cd-Rom.
I remember when I installed this drive I couldn't even get the PC to
recognize it. This was months ago. Then I realized that the drive was
factory defaulted to ATA 100 - faster than my MxBoard could handle. I used
their utility program to step it down to 66. Now I know in the post screen
it said 66 for the past several months.
A few days ago, I slaved this drive on a another PC to transfer files. My
drive has three partitions, one being 40 Gig. I couldn't figure out why the
other PC could only see the first two partitions. So while I troubleshot the
problem, I stepped it down to ATA 33 again. It still didn't work. Then it
dawned on me that this even older PC couldn't recognize partitions bigger
than 32Gig.
No matter. Anyway, I forgot to step my drive back up upon bringing it back
to my PC until this morning. So I used the DLGUDMA utility from does to do
this. It successfully acknowledged the increase. Problem is, it is still
showing up as 33 on my post screen.
I am using WinME and I have tried setting my BIOS to LBA and AUTO. DMA is
also lchecked in Device manager.No change. What am I doing wrong?

 

[MajBach1]

I just figured it out. The Cd-Rom that was on the same cable was slowing it
down. when I removed it, the post screen showed UDMA/66. This brings me to a
follow-up: The cd-burner is a master on the secondary cable and there is no
slave. It posts as ATA/33. This unit is virtually new. Do optical drives
normally run at the transfer rate? Dma is enabled in windows and again, BIOS
is set to auto. Yeah, I have an 80 pin cable..

 

[Eric Gross]

Yes, none of the optical drives I have used supported > UDMA/33. I'm
guessing some higher end drives out there may exist that support UDMA/66,
but none of the common ones do. I'm guessing this is mostly a decision due
to cost, since there really aren't any optical drives that come close to
sustaining 30+MB/sec. On hard drives it is somewhat different, since the
sustained rates are faster, data can be transfered from the buffer at the
full interface rate (the 8MB buffers on newer drives helps a lot compared to
the 128KB reading buffer on most optical drives), and multiple high-speed
hard drives often share the same controller.

-Eric Gross