Ezio wrote:
>My system is [snip] 2 x 18GB SCSI Ultra160 IBM 10Krpm
>All of them are pumping 30MB/s EACH !
>Moreover ... SCSI can let you have many I/O operation at the same time
on
>each unit and on several units ... IDE doesn't and the slowest IDE is
>arbitrating the clock of the channel.
I know we've been here before but I'll say it anyway - a pair of IBM 7200rpm
UDMA100 drives connected to a Promise RAID card will give very good performance
although *not* as good as SCSI but for a *hell* of a lot less dollars.
I finally upgraded my PC to use the Promise card instead of the onboard
IDE and the Fujitsu drive now reports an average 24MB/s using HDTach, and
6% CPU utilisation.
The slowest IDE device *used* to arbitrate the channel but this is no longer
true. When I was disappointed with the amount of time to open a scan with
Paintshop Pro, I ran a test to be sure that the UDMA2 CDROM drive wasn't
slowing down the UDMA5 hard drive. It didn't. Having the CDROM drive connected
or disconnected made no difference to the performance. It turns out that
Paintshop Pro is slowing down the process somehow - opening the sample file
in PSP took 5 seconds, but in Windows Imaging or Irfanview it only took
1 to 2 seconds.
Yes, SCSI hard drives are wonderful, but for those who don't already have
a SCSI 3 interface card, the cost for the difference in performance is getting
harder to justify. I have a UW interface on my computer's motherboard which
is unused due to the cost of LVD drives. :(
Rob
PS The on-topic bit of this message is the observation about opening files
in PSP - I suspect that a faster CPU will get closer to the speed of opening
in the other programs. I think PSP is taking up clock cycles with the LZW
decompression or something similar. I'd need to test loading an uncompressed
file to be sure.
Rob Geraghty [EMAIL PROTECTED]
http://wordweb.com
