Jonathan Sachs wrote in message
...
Rod Speed wrote

The short story is that its only simultaneous ops on a
pair of drives that benefits from having that pair on a
separate channel. Thats pretty uncommon in practice...

I think your entire argument assumes that the
computer is being used to do one thing at a time

Nope. What matters is how often there is significant
drive activity on more than one drive at a time.

And SCSI cant transfer data simultaneously from more
than one drive at a time anyway, ALL it can do is allow
one drive to seek while another is transfering data etc.

-- something which, for me, is emphatically not true.
It's common for me to have a dozen windows open at once,
and two or three applications actively working simultaneously.

Yes, but what matters is how intensively each of those apps
is using the drive(s) its using. With say burning a CD from the
hard drive, the app normally does that sequentially. And what
matters is whether the app can get frequent enough access
to the hard drive to get enough data to keep the burner happy
when that output rate is MUCH lower than the hard drive.

What if I'm writing a document while referring
to information on a DVD ROM or CD ROM?

The app thats used to write the document is hardly ever
using the hard drive, just when you save the document
occassionally. So that app isnt using the hard drive and the
ROM drive literally simultaneously in a data transfer sense.

Since I have carpal tunnel syndrome, I depend
on speech recognition software to write, and it is
quite disk intensive (as well as CPU intensive).

Sounds like its rather badly design or
you dont have enough physical ram.

In that situation, sharing an IDE channel between
the DVD/CD drive and one of my hard disks could
be like trying to eat dinner with one hand.

Nope, nothing like it in fact. And you just have the hard
drive on a different channel to the DVD/CD drive anyway,
no need for a separate channel for every one of the drives.

And SCSI cant do simultaneous data transfers
anyway, in some ways its even worse with just
one bus instead 2 with standard IDE.

The only real advantage SCSI has is that a slow seeking
drive can disconnect from the bus while its seeking etc.
IDE achieves an even better result with 2 channels
because there isnt even any need to disconnect.