HP dc7608 manual Pata Drive Installation Guidelines, Pata Power Cable, Pata Device Classes

Serial and Parallel ATA Drive Guidelines and Features

4.4.2 PATA Power Cable

Pin	Usage
1	+12 V
2	Ground
3	Ground
4	+5 V

4.5 PATA Drive Installation Guidelines

The computer system boards for these products have one Parallel ATA (PATA) channel with a single connector. The channel can have up to two devices attached to it. All drives are connected to the channel using an industry-standard 80-conductor cable.

✎The industry-standard 1.44 MB diskette drive has its own separate channel and is not included as a part of the maximum four drives.

Each drive attached to a channel must have a drive designation. If a drive is attached to the Device 0 cable position and its cable-select jumper is present, the drive is designated as Device 0. Similarly, if a drive is attached to the Device 1 cable position and its cable-select jumper is present, the drive is designated as Device 1.

For optimal performance of a computer system, all drives need to be attached to the PATA channel(s) in a specified sequence. This sequence is determined by the device class of the drives and by specific attach sequence rules.

4.5.1 PATA Device Classes

In order to determine the best drive attach sequence, ATA/ATAPI drives are segregated into four different classes based upon the bandwidth demands they place on an ATA channel. The most demanding devices are in Class 1 and the least demanding are in Class 4.

Class 1	Class 2	Class 3	Class 4
Hard	High Speed	Optical Storage	Magnetic
Drives	Optical Drives	Drives	Storage Drives
Supported	DVD	R/W CD-ROM	Zip
only on USDT	DVD-CD R/W	CD-ROM
chassis with
MultiBay

General Attach Guidelines

■The lower the device class number, the faster the device and the more bandwidth required.

■Drives installed in the Device 0 position receive the greatest possible bandwidth.

■The bootable ATA hard drive should always be installed in the Device 0 position.

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