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I found a missing section on my 80 conductor cable that was connected
to my 30GB Westerndigital drive. It was wire number 76 from the pin
one position on the cable and it had a 3 mm section missing. At
closer examination under a microscope showed that the wire was cut
with some type of tool as it hads zagged edges along the sheath and
the wire stands all chiseled in the same direction. With all this
stated, do you have an opinion on what this would allow the drive to
do or not do. Could it bypass say encrypted data or make it
compatable with a differant buss technology? Would that missing
section allow someone to gain access to just the boot section, like
the master boot record?
Any ideas on why this would be will be of benefit as this has me
puzzled. Jon
The 40-pin ribbon cables were ATA-1 to ATA-4 spec. The 80-wire/40-pin
ribbon cables are ATA-5 and ATA-6 spec.
http://www.t13.org/ has the
specs (if you can find the link) but they usually want to sell them at
www.ansi.org at $18 apiece.
Pin 1 is still pin 1 (for signal) whether a 40- or 80-wire cable. The
extra 40 ground wires are the even numbered ones that are between the
signal wires which are the odd numbered ones. That's why I have to
wonder if you miscounted the wire with the break. Was it really the 5th
wire from the other side of the 80-wire ribbon cable? If not, the break
is on a ground wire (so reduction of crosstalk might be compromised).
Since the odd wires are the signals that connect to the pins in the
connectors, conductor N (where N is odd) goes to pin (N+1)/2; that is,
wire N = pin (N+1)/2, or alternately pin N = wire 2N-1. If you really
meant wire 75 or 77 then you're talking about pins 37 and 38.
Wire 75 = pin (75+1)/2 = pin 37 = CS1 (Chip Select 1), aka -CS1FX
Wire 76 = ground line
Wire 77 = pin (77+1)/2 = pin 38 = CS3 (Chip Select 3), aka -CS3FX.
I'm no cabling or drive interface wizard. Tis easy 'nuff to just do a
Google search to find references, like
http://snurl.com/39wj or
http://snurl.com/39wv. I didn't bother to lookup more detailed articles
that describe the function of each signal, but did glance at
http://www.pcguide.com/ref/hdd/if/ide/confCable80-c.html (the only place
I found that mentions how an old style 40-wire gets detected when an
80-wire cable is required for ATA/66 and higher),
http://snurl.com/39wm,
and
http://www.t13.org/project/d0948r4c.pdf.
I don't know why other respondents focused on Cable Select (CS) which is
pin 28 or wire (28*2)-1, or wire 55, in an 80-wire cable as Steven67
already pointed out. You'd have to be short by a count of 20 wires to
be looking at cable select. 3mm is too big to be from a tool falling
onto the floor where the cable lay. You mentioned zagged edges along
the other nearby wire which means the 3mm section was pulled out instead
of cut out (cutting would not have left a jagged edge). Sounds more
like the cable got wrapped around something sharp or was damaged but
luckily in a wire that probably won't hurt much regarding functionality
although I don't know in regards to its reduction in crosstalk.
