As far as working in another PC, he means as a slave drive, not a primary drive. You will add this to the boot drive, and see if you can access it that way.
As far as the IDE cable, yes and no to answer your question... The drives have jumper pins, which will force master/slave, and usually if there is no pin present, it will default to cable select. With cable select, the drive priority depends on where it is connected.