I have yet to figure out why they couldn't have
done the disk reads/writes
in the background while you do some other things. I believe it's likely to
be a "left-over" from early days.
Certain hardware could do background read/write starting with 7.5.3 (?
maybe .5). I used to do it with my Quarda 610. Also, as of OS 8.0,
read/write can be done in the background on all hardware that supports OS
8.0 (32 bit clean, 040's or better). I regularly put long file copies in
the background and continue doing other things.
-chris
<http://www.mythtech.net>