Overview of the iMac Developer Note
This chapter provides an overview of the hardware and software features of the current models of the iMac.
In this section:
New Features
Feature Set
Comparison of 15”, 17”, and 20” iMac Features
System Software
New Features
New features are listed here with links to the sections that describe them. For a comparison of 15”, 17”, and 20” iMac features, see Table 1-1.
Display: The iMac has a built-in 20-inch widescreen flat-panel, 17-inch widescreen flat-panel, or 15-inch flat-panel display (measured diagonally). The 20” display is new for this release. For more information, see “Flat Panel Display.”
Processor and speed: The microprocessor in the iMac is a PowerPC G4 with a clock speed of 1 GHz in the 15” configuration and 1.25 GHz in the 17” and 20” configurations. For more information, see “PowerPC G4 Microprocessor.”
Graphics acceleration: The AGP 4X graphics IC used in the iMac is an nVidia GeForce4 MX in the 15” configuration and an nVidia GeForce FX 5200 Ultra in the 17” and 20” configurations. For more information, see “Video Display Subsystem.”
Wireless keyboard and mouse: The iMac supports the Apple wireless keyboard and mouse.
Feature Set
Here is a complete list of the features of the iMac. Each feature is described in more detail in a later section.
Processor and speed: The microprocessor in the iMac is a PowerPC G4 with a clock speed of 1 GHz in the 15” configuration and 1.25 GHz in the 17” and 20” configurations. For more information, see “PowerPC G4 Microprocessor.”
Cache: The backside 256 KB 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 computer comes with 256 MB of DDR333 SDRAM installed in an internal 184-pin DIMM expansion slot, with a build-to-order option of 512 MB. A second user-accessible slot accepts an SO-DIMM with up to 512 MB. The maximum supported memory is 1 GB. For more information, see “System RAM.”
Hard disk storage: The built-in hard disk is 7200 rpm with a capacity of 80 GB and a 160 GB build to order option. For more information, see “Hard Disk Drive.”
SuperDrive: The 17” and 20” configurations of the iMac have a SuperDrive (CD-RW/DVD-R). For more information, see “SuperDrive (CD-RW/DVD-R).”
Combo drive: The 15” configuration of the iMac has a combination CD-RW/DVD-ROM drive. For more information, see “Combo (CD-RW/DVD-ROM) Drive.”
Display: The iMac has a built-in 20-inch widescreen flat-panel, 17-inch widescreen flat-panel, or 15-inch flat-panel display (measured diagonally). The 20” display is new for this release. For more information, see “Flat Panel Display.”
USB 2.0 ports The computer has three USB 2.0 ports; see “USB Interface.”
System bus: The speed of the system bus is 167 MHz. For more information, see “Memory and I/O Device Controller.”
Graphics acceleration: The AGP 4X graphics IC used in the iMac is an nVidia GeForce4 MX in the 15” configuration and an nVidia GeForce FX 5200 Ultra in the 17” and 20” configurations. For more information, see “Video Display Subsystem.”
Video RAM: The video hardware in the iMac includes 32 MB (15” configuration) or 64 MB (17” and 20” configurations) of DDR SDRAM, which supports 3D features and millions of colors in all resolutions. For more information, see “Video Display Subsystem.”
External video port: The external display connector supports VGA, composite and S-video formats for devices such as monitors, projectors, and television sets. The Apple VGA adapter is available to connect with a VGA display. A video adapter with composite and S-video connectors is available separately. For more information, see “Video Monitor Port.”
FireWire 400 ports: The iMac has two IEEE-1394a FireWire 400 ports, which support transfer rates of 100, 200, and 400 Mbps. For more information, see “FireWire 400 Connector.”
Target disk mode: The computer can be configured like a FireWire storage device connected to another computer. See “Target Disk Mode.”
Modem: The iMac has a built-in V.92 modem with a 56 Kbps data rate. For more information, see “Internal Modem.”
Ethernet: The iMac has a built in Ethernet port for a 10Base-T and 100Base-TX operation. For more information, see “Ethernet Port.”
AirPort Extreme (optional): A 54 Mbps AirPort Extreme Card is available as a build-to-order option or as a user-installable upgrade. For more information, see “AirPort Extreme Wireless Support.”
Bluetooth (optional): Fully-integrated Bluetooth is available as a build-to-order option to enable short-range wireless connections between desktop and laptop computers and a host of other peripheral devices. For more information, see “Bluetooth Technology.”
Sound: The iMac includes external Apple Pro Speakers, a built-in speaker and microphone, stereo headphone jack, Apple Speaker minijack, and audio line-in. For more information, see “Sound System.”
Keyboard: The iMac comes with an Apple Keyboard. The keyboard is also a USB hub with two USB 1.1 ports. For more information, see “Keyboard Features.”
Mouse: The iMac comes with an Apple Mouse, a USB mouse with optical tracking. For more information, see “Mouse.”
Wireless keyboard and mouse: The iMac supports the Apple wireless keyboard and mouse.
Comparison of 15”, 17”, and 20” iMac Features
Table 1-1 provides a quick comparison of the features of the configurations of the iMac computer.
15” iMac |
17” iMac |
20” iMac |
|
|---|---|---|---|
CPU and speed |
PowerPC G4 1 GHz |
PowerPC G4 1.25 GHz |
PowerPC G4 1.25 GHz |
System bus speed |
167 MHz |
167 MHz |
167 MHz |
Main memory |
256 MB, 333 MHz DDR SDRAM, supports expansion up to 1 GB |
256 MB, 333 MHz DDR SDRAM, supports expansion up to 1 GB |
256 MB, 333 MHz DDR SDRAM, supports expansion up to 1 GB |
Display |
Built-in 15-inch flat panel |
Built-in 17-inch, widescreen flat panel |
Built-in 20-inch, widescreen flat panel |
Graphics IC |
nVidia GeForce4 MX |
nVidia GeForce FX 5200 Ultra |
nVidia GeForce FX 5200 Ultra |
Graphics memory |
32 MB DDR RAM |
64 MB DDR RAM |
64 MB DDR RAM |
Power supply |
160 W |
160 W |
190 W |
Hard disk drive |
80 GB Ultra ATA-100 7200 rpm |
80 GB Ultra ATA-100 7200 rpm |
80 GB Ultra ATA-100 7200 rpm |
Optical drive |
Tray-load Combo drive |
Tray-load SuperDrive |
Tray-load SuperDrive |
External monitor port |
VGA output port/S-video and composite video output |
VGA output port/S-video and composite video output |
VGA output port/S-video and composite video output |
Data ports |
Three external USB 2.0 ports plus two USB 1.1 ports on keyboard; two FireWire 400 ports |
Three external USB 2.0 ports plus two USB 1.1 ports on keyboard; two FireWire 400 ports |
Three external USB 2.0 ports plus two USB 1.1 ports on keyboard; two FireWire 400 ports |
Comm features |
10/100 Ethernet; 56K V.92 fax modem |
10/100 Ethernet; 56K V.92 fax modem |
10/100 Ethernet; 56K V.92 fax modem |
Wireless features |
Optional 54 Mbps AirPort Extreme Card; optional internal Bluetooth |
Optional 54 Mbps AirPort Extreme Card; optional internal Bluetooth |
Optional 54 Mbps AirPort Extreme Card; optional internal Bluetooth |
Sound features |
Built-in speaker and microphone; stereo headphone jack and Apple Pro Speaker minijack; external Apple Pro speakers, audio line-in |
Built-in speaker and microphone; stereo headphone jack and Apple Pro Speaker minijack; external Apple Pro speakers, audio line-in |
Built-in speaker and microphone; stereo headphone jack and Apple Pro Speaker minijack; external Apple Pro speakers, audio line-in |
System Software
The 15” and 17” iMac come with Mac OS X version 10.2.7 or later installed; the 20” iMac comes with Mac OS X version 10.3 or later installed. Mac OS 9 applications can be run in Classic mode. For more information about Mac OS X, see the reference listed in “Mac OS X.”
Machine Identification
Apple Computer discourages the targeting of code to specific machine models. However, if it is necessary to identify a machine in order to determine the features of the machine, applications can use the IORegistry with Mac OS X. Or, in many cases, it is feasible to use Gestalt calls to test a machine for specific features.
Asset management software that reports the kind of machine it is run on can obtain the value of the property at Devices:device-tree:compatible in the Name Registry. The model string is the first program-usable string in the array of C strings in the compatible field. The value of the string in the compatible property is PowerMac6,3.
The string obtained from the compatible property cannot be displayed to the computer user. If it is available, use the result from calling Gestalt ('mnam', &result) where result is a string pointer. This call returns a Pascal style string that can be displayed to the user.
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 website:
http://developer.apple.com/hardwaredrivers/ve/index.html
For more information, please see the references at “Velocity Engine.”
© 2000, 2003 Apple Computer, Inc. All Rights Reserved. (Last updated: 2003-12-11)