IDE Cable Questions

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

"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*

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

Brandon wrote:

> 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?

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.


>
> -Brandon

--
--John
Reply to jclarke at ae tee tee global dot net
(was jclarke at eye bee em dot net)

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

"J. Clarke" <jclarke@nospam.invalid> wrote in message news:cjbcnl01lvm@news4.newsguy.com
> Brandon wrote:
>
> > 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?
>
> 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.

But that was in another century.

>
>
> >
> > -Brandon

Archived from groups: comp.sys.ibm.pc.hardware.storage (More info?)

"Folkert Rienstra" <see_reply-to@myweb.nl> wrote in message
news:2ru9riF1eujjmU4@uni-berlin.de...
>
> "J. Clarke" <jclarke@nospam.invalid> wrote in message
news:cjbcnl01lvm@news4.newsguy.com
> > Brandon wrote:
> >
> > > 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?
> >
> > 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.
>
> But that was in another century.

But your contribution was a simple troll as most of yours are becoming.