IDE Cable Questions

I have a few questions but I'm not sure if this is the right place to
ask. If it's not, please point me in the right direction.

First, is it okay to run a drive's power cable parallel to its IDE
ribbon? I know that sometimes in electronics that's not the best idea
because power cables can interfere with the signals of nearby wires.
I don't know if that would apply in this situation though since the
signals are digital.

Second, if two drives were connected to a single IDE ribbon and both
were set as the master but only one drive was connected to the power
source at a single time, would this cause conflicts? It seems to me
that the unconnected drive would be non-existant as far as the
computer was concerned but I could be completely wrong. Perhaps the
ribbon provides enough power for the drive to respond to simple low
level "I'm here but I am not in working condition" commands that might
cause a conflict. Does anyone know for sure?

-Brandon

"Brandon" asked:
 > First, is it okay to run a drive's power cable parallel to its IDE
 > ribbon?

The power cable has DC voltage and power supply noise
is *probably* filtered out. An 80-wire ribbon cable sandwiches
each data wire between grounded wires which shield the
data wires *somewhat*. Since there's nothing to keep the
two cables apart, it's *probably* OK to let them run parallel
and in contact, but I'd still try to avoid as much proximity
between the two as I could.


 > Second, if two drives were connected to a single IDE ribbon and both
 > were set as the master but only one drive was connected to the power
 > source at a single time, would this cause conflicts? It seems to me
 > that the unconnected drive would be non-existant as far as the
 > computer was concerned but I could be completely wrong. Perhaps the
 > ribbon provides enough power for the drive to respond to simple low
 > level "I'm here but I am not in working condition" commands that might
 > cause a conflict. Does anyone know for sure?


The no-no here is when the end HD is "dead", the cable leading
to it may cause signal reflections - IF it acts the same way as the case
with no HD at the end. There was a heated argument here about
whether signals are absorbed by a "dead" HD, or whether it acts as
an open circuit (and causes signal reflections), and though I doubt
that anyone here knows for sure, the concensus by virtue of bull-
headedness was that it acts as an open circuit and thus "dead" HDs
at the end position are to be avoided. It would be a great contribution
to this NG if you tried booting up a HD at the intermediate position on
the cable while an unpowered HD was connected at the end position
and you reported back your observations to us.

*TimDaniels*<!-- ~MESSAGE_AFTER~ -->