slave and master drives - which order on ribbon?

[Frank Marshall]

Greets,

I've seen the answer to this a long time ago but can't find it using the search function. For the best performance from a (master) video scratch disk on the second UDMA33 channel (which also has to share a (slave) CD/RW device) does the slave or master go on the end of the ribbon or on the connector in the middle of the ribbon?

Ta.

[Dr Mordrid]

There are electrical signaling issues if you connect a single drive to the middle connector with the end connector unattached. UDMA is also not supported in this configuration.

Attaching two drives may be different, but I'd go with masters on the end connector just to be sure.

Dr. Mordrid

[Brian Ellis]

IMHO, no difference that I've been able to measure.

[Dr Mordrid]

The new 80 wire cables were first defined in the original UDMA spec for modes 0, 1 and 2. The 80 wire cable is optional for those modes, which is why you still see the old 40 wire cables laying around.

For any UDMA modes above mode 2, however, the 80 wire cable is mandatory.

Also, there are connections on the old 40 wire cables that are illegal in the new 80 wire spec. Also, pin 34 is used to sense if an 80 wire cable is present so that newer mainboards can turn on UDMA for compatable devices.

These changes, among others, brought about the need to lay down a spec specifying what goes where.

Quote from the PC Guide:

For the first time, the 80-conductor cable defines specific roles for each of the connectors on the cable; the older cable did not. Color coding of the connectors is used to make it easier to determine which connector goes with each device:

Blue: The blue connector attaches to the host (motherboard or controller).

Gray: The gray connector is in the middle of the cable, and goes to any slave (device 1) drive if present on the channel.

Black: The black connector is at the opposite end from the host connector and goes to the master drive (device 0), or a single drive if only one is use

Dr. Mordrid