Apple Setting Up Your Power Macintosh G4 (PCI & AGP) - Manual (Page 30)

30 Chapter 2
SCSI Drives
If you purchase and install a SCSI PCI card, you can connect additional internal SCSI hard
drives. You can connect up to three internal SCSI drives (if you remove the Ultra ATA drive
that comes in standard configurations) and connect additional external SCSI devices to the
card if it provides a port on the rear of the computer.
You must assign a SCSI ID number to every SCSI device you install and the number must not
conflict with the ID number already assigned to a device on the SCSI chain. Your SCSI PCI
card also requires a unique SCSI ID.
Other Types of SCSI Devices
You can connect some other types of SCSI devices to your Macintosh. To do this, you need to
add a PCI card that supports the device.
Instructions for PCI card installation appear in the section “Installing a PCI Expansion Card”
on page 49. Instructions for drive installation appear in the section “Installing a Hard Disk or
Other Internal Storage Device” on page 38.
For more information about using different types of SCSI devices with your computer, see
the Tech Info Library at Apple’s Web site: til.info.apple.com
About PCI Expansion Cards
Your Macintosh can accommodate additional printed circuit boards (cards) for video and
graphics applications, networking and communications, additional processing power, or
other purposes. The cards fit into connectors, called expansion slots, inside the computer.
Your Macintosh has four expansion slots, each of which accepts a PCI card up to 12 inches
long. Install only expansion cards that come with Macintosh driver software and that comply
with the PCI 2.1 standard. NuBus
™
cards cannot be used in these expansion slots.
In standard Macintosh models, a graphics card that supplies a monitor port occupies the PCI
slot labeled number 1. This slot can accommodate 3.3 volt ( V ) cards with 66 MHz frequency
and 32-bit data widths only.
The other three PCI slots can accommodate mixed voltage (5.0 V or 3.3 V ) cards with a
33 MHz frequency and 32-bit or 64-bit data widths. To use a 66 MHz card in one of these
three slots, the card must be designed to function at both 66 MHz and 33 MHz; it will work at
the lower 33 MHz frequency when installed.
Warning Do not use cards that function at only 66 MHz in these three PCI slots. Damage
to your equipment could result. If you have a 66 MHz card, check the card’s manufacturer
to see if it also works at 33 MHz.