Step 2: Opening The Computer - IBM OPTIONS SCSI Manual Del Usuario

SCSI IDs for your devices.
SCSI device
Startup hard disk drive (boot drive)
Tape drive
CD-ROM drive
High density diskette drive
Removable hard disk drive
Other hard disk drive
Other hard disk drive
SCSI adapter
Additional hard disk drives
For more information on setting SCSI IDs, use the following guidelines:
v You cannot assign the same ID to multiple devices on the same
single-channel SCSI adapter.
v The SCSI adapter is normally pre-assigned SCSI ID 7.
v While the early SCSI adapters expected the startup drive to be located at
SCSI ID 6, the highest priority ID, more recent SCSI adapters expect the boot
drive to be at SCSI 0. Today's SCSI adapters generally have much more
bandwidth compared to the sustainable data rates of the devices. Placing the
most important drive at the highest priority SCSI ID is no longer important.
However, the other devices in the table are listed in a logical priority
sequence relative to their respective performance.
v Narrow (50-pin) SCSI devices, such as Zip drives, Jaz drives, or low-end
tape drives, can connect to the wide bus only through a
50-pin-device-to-68-pin-cable converter (IBM part number 32G3925).
Alternatively, some adapters have a 50-pin connector for 50-conductor
cabling to narrow devices.
v Mixing any SCSI devices that do not support Ultra2 (80 Mbps) or faster data
rates on an Ultra2 or newer bus, reduces the fastest supported rate of the
bus to 40 Mbps. The shorter pre-Ultra2 cable length limitations must be
followed for acceptable data integrity.
v Before installing the new drive, determine which SCSI IDs are already
assigned to avoid assigning duplicate IDs.

Step 2: Opening the computer

To open your computer, you must first unplug the power cords for the
computer and all attached devices. For specific information on opening your
computer, see the documentation that comes with your computer.
1-4
SCSI Hard Disk Drives for IBM PCs: User's Guide
SCSI ID
0
1
2
3
4
5
6
7
8-15