HP Xw6200 - Workstation - 2 GB RAM, Technical Reference Manual

Page: 160 / 209

160
ULTRA ATA DEVICES
NOTE 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.
Any drive attached to a controller must have a drive designation. If only a single drive is connected to a controller
and its jumper is in the cable-select position, it is designated as the Master Drive (Drive/Device 0) by its attachment
to the Drive/Device 0 cable position. If two cable-selected drives are connected to a single controller, one will be
designated by its attachment to the cable as the Master (Drive/Device 0) and the other as Slave (Drive/Device 1).
For optimal performance of a workstation system, all drives must be attached to the ATA controllers in a specified
sequence. This sequence is determined by the device class of the drives and by specific attach sequence rules.
Device Classes
To determine the best drive attach sequence, ATA/ATAPI drives are segregated into four different classes based on
the bandwidth demands they place on an ATA controller. The most demanding devices are in Class 1 and the least
demanding are in Class 4.
General Attach Guidelines
„
The lower the device class number, the faster the device and the more bandwidth required.
„
Drives installed in the Device 0 positions on both the primary and secondary controllers receive the greatest
possible bandwidth.
„
The bootable ATA hard drive should always be installed on the primary controller in the Device 0 position.
Attach Sequence Rules by Class Priority
Drives should be attached in the sequence shown for optimum performance starting at position 1 .
Figure C–1 Installing Drive Order
Table C-1 Device Classes
Class 1
Hard
Drives Class 2 High Speed
Optical Drives Class 3 Optical Storage
Drives Class 4
Magnetic Storage Drives
ATA-100
ATA-66
ATA-33 DVD
DVD-CD R/W R/W CD-ROM
CD-ROM LS-120
Tape
Zip
1
2
4
3
Primary
Controller* 4 1
Secondary
Controller 3 2
Device 1 Device 0