Overview of eMac

This chapter lists the features of the eMac computer and provides information about a few software issues of interest to developers.

In this section:

New Features
All Features
External Features
System Software

New Features

The features that have changed are listed here with links to the sections that describe them.

Microprocessor: The eMac computer has a PowerPC G4 microprocessor running at a clock speed of 700 or 800 MHz. For more information, see “PowerPC G4 Microprocessor.”
Memory: The computer comes with 128 or 256 MB of SDRAM installed. For more information, see “RAM Expansion Modules.”
Hard disk storage: The built-in hard disk drive has a capacity of 40 GB for the Combo drive and 60 GB for the SuperDrive drive. For more information, see “Hard Disk Drive.”
Combo (DVD-ROM/CD-RW) drive: One configuration has a combination DVD-ROM/CD-RW drive. For more information, see “Combo Drive DVD-ROM/CD-RW.”
SuperDrive (DVD-R/CD-RW) drive: One configuration has a SuperDrive (DVD-R/CD-RW) drive. For more information, see “SuperDrive DVD-R/CD-RW Drive.”

All Features

Here is a complete list of the features of the eMac computer. Each feature is described in more detail in a later section.

Processor: The eMac computer has a PowerPC G4 microprocessor running at a clock speed of 700 MHz or 800 MHz. For more information, see “PowerPC G4 Microprocessor.”
Cache: The 256-kB backside L2 cache is included on the microprocessor IC and has the same clock speed as the microprocessor. For more information, see “Level 2 Cache.”
Memory: The eMac computer comes with 128 or 256 MB of SDRAM installed in one of two standard 168-pin DIMM expansion slots. The RAM slots can support up to 512 MB each for a maximum total of 1 GB. For more information, see “RAM Expansion Modules.”
Hard disk storage: The built-in hard disk drive has a capacity of 40 GB for the Combo drive and 60 GB for the SuperDrive. For more information, see “Hard Disk Drive.”
CD-RW drive: One configuration has a CD-RW drive. For more information, see “CD-RW Drive.”
Combo DVD-ROM/CD-RW drive: One configuration has a combination DVD-ROM/CD-RW drive. For more information, see “Combo Drive DVD-ROM/CD-RW.”
SuperDrive (CD-RW/DVD-R) drive: One configuration has a SuperDrive (CD-RW/DVD-R) drive. For more information, see “SuperDrive DVD-R/CD-RW Drive”
External video monitor: The eMac has a mini-VGA port for connecting an external video monitor. For more information, see “Video Monitor Port.”
Graphics acceleration: The video circuits provide built-in 2D and 3D acceleration using an NVidia GeForce2 MX IC. For more information, see “Video Display Subsystem.”
Video RAM: The video hardware includes 32 MB of video DDR, which supports 3D features and millions of colors in all resolutions. For more information, see “Video Display Subsystem” and “Video Display.”
USB ports: The eMac has three USB ports on the main chassis and two more on the keyboard. For more information, in “USB Ports.”
FireWire ports: The eMac has two IEEE-1394 FireWire high-speed serial ports, which support transfer rates of 100, 200, and 400 Mbps. For more information, see “FireWire Ports.”
Target Disk Mode: The computer can act like a FireWire storage device connected to another computer. See “Target Disk Mode.”
Modem: The Combo drive and CD-RW models have a built-in V.92 fax modem with a 56 Kbps data rate. For more information, see “Internal Modem.”
Ethernet: The eMac has a built-in Ethernet port for a 10Base-T and 100Base-TX operation. For more information, see “Ethernet Port.”
AirPort Card slot: An internal AirPort Card wireless LAN module is available as a build-to-order option or as a user-installable upgrade. For more information, see “AirPort Card.”
Sound: The eMac has a built-in microphone and two stereo speakers, a line-level stereo input jack, and a stereo headphone jack. For more information, see “Sound System.”
Keyboard: The eMac comes with an Apple Pro Keyboard. The keyboard is also a USB hub with two USB ports. For more information, see “Keyboard.”
Mouse: The computer comes with an Apple Pro Mouse, a USB mouse with optical tracking. For more information, see “Mouse.”
Size and weight: The eMac computer is 40.6 cm (15.8 inches) high, 40.6 cm (15.8 inches) wide, and 40.7 cm (15.9 inches) deep; it weighs 22.7 kg (50.0 pounds).
Display: The eMac computer has a built-in 17-inch flat color CRT monitor with a 16-inch viewable diagonal. For more information, see “Video Display.” For a comparison with the 15-inch CRT iMac, see Table 1-1.

Table 1-1 provides a quick comparison of the features of the eMac computer with those of the iMac 15-inch CRT models introduced in May, 2001.

**Table 1-1** Feature comparison
	iMac 15-inch CRT models	eMac computer
Processor and speed	500, 600, or 700 MHz PPC G3	700 or 800 MHz PPC G4
L2 cache speed	500, 600, or 700 MHz	700 or 800 MHz
System bus speed	100 MHz	100 MHz
Main memory	128 or 256 MB, expandable up to 1 GB	128 or 256 MB, expandable up to 1 GB
Display	15-inch CRT (13.8 inch viewable)	17-inch flat CRT (16-inch viewable)
Graphics IC	ATI RAGE 128 Ultra	NVidia GeForce2 MX
Graphics memory	16 MB, plus AGP expansion	32 MB DDR
Video Output	Mirrored VGA	Mirrored VGA
Hard disk drive	20, 40, or 60 GB IDE drive	40 or 60 GB IDE drive
Optical drive	Slot-load CD-RW drive	Tray-load CD-RW, DVD-ROM/CD-RW, or DVD-R/CD-RWdrive
Data ports	Four USB ports (two on the keyboard); two FireWire ports	Five USB ports (two on the keyboard); two FireWire ports
Communication features	10/100 Ethernet; 56 Kbps fax modem; optional AirPort card	10/100 Ethernet; 56 Kbps fax modem (on Combo drive and SuperDrive models); optional AirPort Card
Sound features	Stereo, with built-in speakers, microphone, and I/O jacks	Stereo, with built-in speakers, microphone, sound input jack, and headphone jack
Keyboard	Apple Pro Keyboard (USB)	Apple Pro Keyboard (USB)
Mouse	Apple Pro Mouse (USB)	Apple Pro Mouse (USB)

External Features

The eMac computer is housed in a polycarbonate plastic enclosure that includes the display. The separate keyboard and mouse are also designed in polycarbonate plastic.

The front of the enclosure is dominated by the 17 inch flat display. The front also includes, below the display, the following features:

Tray-loading CD-RW, SuperDrive, or Combo drive, in the center
Access to Airport card slot
Stereo speakers, one on either side
Power-on light, located near the speaker on the right side; the light has a steady white glow when on; it pulses in Sleep mode.

The right side of the enclosure, as viewed from the front, contains the I/O panel. The I/O panel contains the following features:

Two FireWire ports
Modem connector (on the models that have an internal modem)
Ethernet port
Three USB ports
Video monitor connector (mini-VGA)
Headphone jack
Sound-in jack

The receptacle for the power cord is located on the back. The back panel also includes the following features:

Power button
Kensington lock attachment point

The back portion of the bottom of the enclosure has a door that can be opened for access to the expansion RAM. For more information, see “RAM Expansion Slots.”

System Software

The eMac computer comes with both Mac OS X (version 10.2) and Mac OS 9.2.2 installed. Mac OS X is the default system. (A configuration with Mac OS 9 as the default system is also available for education customers.)

For more information about Mac OS X, see the reference listed in “Mac OS X.” For the latest information about Mac OS 9.2.2, see the reference listed in “Mac OS 9.2.2.”

Computer Identification

Rather than reading the box flag or the model string and then making assumptions about the computer’s features, applications that need to find out the features of the computer should use IORegistry calls to test for the features they require. IORegistry calls are part of the I/O Kit API. For more information, see the references listed at “I/O Kit.”

Asset management software that reports the kind of computer it is run on can obtain the value of the model property from the IOService plane of the IORegistry. For the eMac, the value of the string in the compatible property is PowerMac4,4.

Velocity Engine Acceleration

The Velocity Engine (an implementation of AltiVec) is the vector processing unit in the PowerPC G4 microprocessor. Some system software has been modified to take advantage of the accelerated processing that the Velocity Engine makes possible. System software has also been modified to support low-level operations using the Velocity Engine.

For complete information on the Velocity Engine, refer to the following Apple websites:

http://developer.apple.com/hardwaredrivers/ve/index.html

and

http://developer.apple.com/documentation/Performance/Conceptual/vDSP/vDSP_Library.pdf

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