This article provides specifications for the hard drive, CD-ROM drive, and ATA bus which supports them.

The Power Mac G4 (PCI Graphics) has an Ultra-ATA/33 bus capable of transmitting data (at burst rate) up to 33 Megabytes per second between the hard disk drives and the computer.

Hard Disk Drive

Storage capacity: Varies

Disk transfer (sustained) rate: 8-12 megabytes (MB) per second

Host transfer (burst) rate maximum: 33 MB per second

Master/Slave configurations are supported

Drive bays can accommodate drives up t 1.6 inches high

CD-ROM drive

Disc diameters supported: 120 millimeter (mm) (4.7 inches), 80 mm (3.2 inches)

Data capacity:

656 megabytes (MB), Mode 1

748 MB, Mode 2

Laser :

Type: Semiconductor laser AlGaAs

Wavelength: 775-815 nanometers (nm) (typical 790 nm)

Output powerLaser power: 3.3 milliwatts (mW)

Power out of object lens: 0.2 mW (typical), 0.5 mW (maximum)

Beam divergence

Horizontal: 8°-16° (typical 12°)Vertical: 20°-55° (typical 35°)

DVD-ROM drive

Disc diameters supported: 120 mm (4.7 inches)

Data capacity:

CD 656 megabytes (MB), Mode 1

748 MB, Mode 2

DVD 4.70 gigabytes (GB), single-sided, single-layer

8.5 GB, single-sided, double-layer

9.4 GB, double-sided, single-layer

17 GB, double-sided, double-layer

Laser:

Type: Semiconductor GaAs laser

Wavelength: 650-668 nm (typical 658 nm)

Output power

Laser power: 0.6 milliwatts (mW)

Power out of object lens: 0.95 mW (typical), 2 mW (maximum)

Beam divergence

Horizontal: 7°-11° (typical 8.5°)Vertical: 19°-32° (typical 27°)