i have never understood why 80 thin wires is faster than 40 thicker ones when they’re still terminating in only 40 pins, what’s the secret sauce here? i recognize we’re well past the time where this information is relevant, i was just upgrading an og xbox recently and the thought popped up again.
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If I remember correctly, the extra 40 cables are ground and are used to isolate the signaling cables from each other. This reduces noise and allows faster speeds in practice.
So IDE is also known as Parallel ATA, (ATA stands for AT Attachment referring to the IBM AT the earliest PC.) as opposed to modern Consumer Hard Drives which use a 7 pin data cable for SATA or Serial ATA.
So what does the 80 wire cable do that a 40 wire cable doesn’t? It’s all about grounds and data integrity. Since PATA/IDE each cable is its own data line, each pin needs to transfer data perfectly and reliably so you don’t lose information. The “new” 40 cables are all grounds, which is why they don’t have any new pins and they’re all linked with their original pin to reduce any crosstalk or interference between the data cables. That reduction makes it so you can run the 40 original cables faster.
Parallel wires tend to create interference with each other. By adding an extra wire in between each of the wires in a IDE cable and connecting them to earth/ground you can use those extra wires as shielding for interference between the wires that are actually used to transmit data and that gives you some more headroom for increasing transfer rates. This shielding effect is why those rounded cables that came into vogue in the last few years of PATA drives were such a bad idea – by rounding the cable you were interfering with the shielding effect provided by the extra wires and making it so that the cable couldn’t handle the higher transfer rates as well as a regular 80 wire flat cable could.
For what it is worth, the reason why we went with a serial connection (SATA) after so many iterations of the parallel (PATA) interface is because serial connections can be clocked so much faster without worrying as much about the wires interfering with each other. SATA uses two pairs of wires for transmitting and receiving data, each pair is shielded from the other wires in the cable and differential signalling is used to help filter out noise and interference.