Compaq Service Reference Guide
4-1
chapter
4
IDE/ATAPI D
EVICE
S
EQUENCING
G
UIDELINES
This guideline standardizes the configuration of multiple IDE/ATAPI storage devices. It
categorizes the devices by the type of media used and then ranks the device within each class.
Device Class
Class 1
Hard Drives
Class 2
Magnetic Storage
Class 3
Optical Storage
2.1 LS-120
2.2 Tape Drive
2.3 Iomega Zip Drive
3.1 R/W CD-ROM Drive
3.2 DVD-ROM Drive
3.3 CD-ROM Drive
4.1
General Application Rules
1. When possible, hard drives should be configured by themselves on the primary controller
channel.
2. When devices from all three classes are present, class 2 and 3 devices should be combined first
on the secondary controller channel.
3. When combining two devices on any controller channel, the device with the lower rank should
be the primary device (master) and the higher rank the secondary device (slave).
4. The lowest class present in a configuration consisting of four devices should be placed on the
primary channel with the hard drive.
5. As new devices are developed and added to the individual class lists they will be added to the
bottom of the lists. This improves the chances that the new device will be configured as a
primary drive (master) and lowers the chances that it will be combined with a hard drive.
6. When two hard drives are installed in a computer, an 80-pin cable should be used. When other
multiple ATAPI devices are used, a 40-pin cable is recommended.
4.2
Special Situations
1. When combined with the Iomega Zip drive on the same controller, the DVD drive must be
configured as the primary drive.
2. In all applications except an NLX minitower chassis, when an LS-120 drive is being
configured, it is assumed that the diskette drive is not present.
3. When a DVD drive using A50H firmware and an Iomega Zip drive are on the same controller,
the DVD drive must be configured as the primary drive. When the DVD drive firmware is
A53H, this configuration is not required.
4. DVD drives are supported on some computers that use the Intel 810 chipset. Refer to the
specific documentation that came with the computer for applicability.
