Storage Interfaces

Selecting which of the connectors the devices attach to is critical in optimizing the performance of the IDE/ATA channel. When one device is used, it is best to attach a connector at one end of the cable to the device, and the other end of the cable to the system board. It is not recommended that you attach a device to the middle connector, thus leaving the end connector "dangling"-- this type of configuration allows signal reflection.

When two devices are present, it is best that the end connector attach to the master device and the middle connector to the slave device. The other end of the cable will connect to the system board.

The newer high-speed IDE/ATA controllers, such as ATA-66/ATA-100, require the use of an 80-wire cable. These new cables are backward compatible with the older 40-wire cables. The cable's additional wires are needed to absorb any stray signals or crosstalk associated with the higher speeds. The 80-wire cables define specific roles for each cable connector:

• Blue - attaches to the host controller.

• Gray - the middle connector. It attaches to a slave device (if present).

• Black - the opposite end of cable from the host connector. It attaches to the master device.

Newer IDE cables are still restricted to a maximum length of 18 inches.

Cable Select

Most new devices support an option called cable select. Cable select eliminates the need to designate a device a master or a slave; instead, it designates device roles based on their position on the cable. This option can be configured using a jumper on the drive(s). Both the device and the cable must support cable select for this option to work.