🚀 go-pugleaf

Rod Speed wrote: 

>> Signalling wise, there is no difference between a 40- and 80-wire IDE
>> cable.
<which is qualified in a following paragraph regarding cable select>
> 
> Wrong. 80 wire cables are usually cable select cables, 40 wire cables
> usually are not.

Get an ohmmeter to test.  

http://www.unitechelectronics.com/ide44pinout.gif
(this is the drive header, same pinout as for mobo header; remember to
mirror the image for ribbon connector)

Cable select cables require a pin (#28) not be connected on one of the
device-side connectors.  I already mentioned in my prior post how this can
be done.  The host adapter grounds this signal (i.e., when connected, the
device sees a ground line).  If pin 28 is connected at the device (i.e., the
device sees this signal is grounded), it is the master device.  If this pin
is open (floating), that device is the slave.

Just get a continuity tester to determine in pin 28 is open on one of the
device connectors on the ribbon cable.  I have 80-wire, 40-pin cables that
have pin 28 connected and some where it is open.  I have not seen a
predominance of one or the other to claim a "usual" configuration, and
because of this is why I test.  It all depends on who manufactured the
cable.  For example, the manufacturer might want that same 80-wire cable to
be usable in 40-wire cable setups so they feed pin 28 to all connectors.
The same holds true as to whether the connector or shroud are polarized with
a tang or notch, if depolarized by the absense of a tang or having notches
on both sides of the shroud, or if pin 20 is used as a polarizing key (by
pin 20 missing in header and blocked or solid in the connector).  You have
to look.  For cable-select or not enforced in the manufacture of a 80-wire
ribbon cable, you have to check with a continuity check.

If the connectors on the ribbon cable are color coded, I would suspect
cable-select was enforced through the physical connections as follows:

  - Blue:  Motherboard.    Pin 28 connected.
  - Black: Master device.  Pin 28 connected.
  - Gray:  Slave device.   Pin 28 not connected.

But I'd still check pin 28 with a continuity tester to make sure.  You may
not have cable-enforced cable-select with some 80-wire ribbon cables (i.e.,
pine 28 goes to all connectors) when you want to use cable-select on the
device jumpers.  You may not want cable-enforced cable-select if you are
using jumpers on the devices to configure them as master and slave.  Whether
you have a cable-select cable is something you should really test.