IDE Cable Questions

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Brandon

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?
Click to expand...

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?
Click to expand...


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*
 
Brandon said:
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?
Click to expand...

Regardless of any other considerations, a powered down drive can cause data
corruption on the other drive. In some cases it can even cause corruption
of data on drives on the other IDE channel, depending on how well the
particular chipset isolates the channels.

Found that out the hard way.
 
J. Clarke said:
Regardless of any other considerations, a powered down drive can cause data
corruption on the other drive. In some cases it can even cause corruption
of data on drives on the other IDE channel, depending on how well the
particular chipset isolates the channels.
Click to expand...
Found that out the hard way.
Click to expand...

But that was in another century.
 
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