Overview of the 15-inch PowerBook G4

This chapter outlines the features of the 15-inch PowerBook G4, with emphasis on the changes from the previous models.

New Features

The features that have changed are listed here along with references to the sections that describe them. For a quick summary of the feature comparison of these models to the previous release models, see Table 1-1.

Table 1-1  Feature comparison

Feature

Previous model

Current model

Processor

PowerPC G4

Enclosure

aluminum alloy

Processor clock speed

1.33 GHz or 1.5 GHz

1.5 GHz or 1.67 GHz

Graphics IC

ATI Mobility Radeon 9700

System bus speed

167 MHz

Device ports

2 USB 2.0; 1 FireWire 400 ; 1 FireWire 800

Graphics memory

64 MB of DDR; 128 MB BTO

64 MB of DDR; 128 MB with dual link DVI BTO

Hard disk drive

4200 rpm 60 or 80 GB 5400 rpm 80 GB BTO.

5400 rpm 80 GB. 5400 rpm 100 GB BTO.

Keyboard

backlit keyboard and ambient light sensors on 1.5 GHz and BTO on 1.33 GHz

Backlit keyboard and ambient light sensors standard on all configs. Backlit keyboard ten times brighter.

RAM

256 MB or 512 MB DDR333 SDRAM SO-DIMMs with 2 GB expansion capacity

512 MB DDR333 SDRAM SO-DIMMs with 2 GB expansion capacity

Wireless

standard AirPort Extreme and fully-integrated Bluetooth 1.1

standard AirPort Extreme and fully-integrated Bluetooth 2.0 +EDR

Battery

50 watt-hours battery

Power adapter

65 W power adapter

Sudden Motion Sensor

not available

new feature

Scrolling Trackpad

not available

new feature

Removable media

Combo drive or a 4x SuperDrive

Combo drive or an 8x SuperDrive

note: BTO — build to order

All Features

Here is a list of the features of the 15-inch PowerBook G4. Each feature is described in a later chapter, as indicated in the list.

Appearance

Figure 1-1 is a front view of the 15-inch PowerBook G4 computer. Figure 1-2 provides side views that show the I/O ports.

Figure 1-1  Front view of the computer
Front view of the computer
Figure 1-2  Side views showing I/O ports
Side views showing I/O ports

Peripheral Devices

In addition to the devices that are included with the computer, several peripheral devices are available separately:

System Software

The 15-inch PowerBook G4 comes with Mac OS X version 10.3.7 installed and runs Mac OS 9 applications in Classic mode. For the latest information, see the references listed in Mac OS X.

Here are a few items of interest about the system software on the 15-inch PowerBook G4.

Open Firmware

System software on all current Macintosh models uses a design based on Open Firmware. With this approach, the ROM on the main logic board contains only the Open Firmware code needed to initialize the hardware and load an operating system. The rest of the system code is loaded into RAM from disk or from the network. For more information, see the references listed in Open Firmware.

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 running on can obtain the value of the model property from the IOService plane of the IORegistry. For the 15-inch PowerBook G4, the value of the model property is PowerBook5,6.

Power Management

Apple’s power management techniques for the 15-inch PowerBook G4 are described in the following paragraphs.

Power Saving States

The power management protocols on the 15-inch PowerBook G4 support two power-saving states: idle and sleep.

  • Idle: The system is idling with the main processor in a low-power state. All clocks are running; the system can return to running code within a few nanoseconds. Cache coherency is maintained in this state. The CPU automatically transitions between run and idle, independent of the operating frequency. The operating frequency is based on the processor power management setting. For additional information, see Processor Power Management.

  • Sleep: Most internal components are powered off and the state is saved; the DRAM state is preserved for quick recovery. All processors are powered off with their state preserved in DRAM. All clocks in the system are suspended except for the 32.768 kHz timebase crystal on the PMU99 IC.

The computer automatically enters idle state after a few hundred miliseconds of inactivity. If the computer is attached to a network, it is able to respond to service requests and other events directed to the computer while it is in idle state.

While it is connected to an AC power supply, the computer can also respond to network activity when it is in sleep state. The user can enable this feature by selecting Wake-on-LAN in the Energy Saver preference pane.

When operating on the battery in sleep state, the computer consumes less than 1 watt of power, meeting the Energy Star power-saving standard. When operating on the power adapter in sleep state, the combined computer and adapter consume 3 to 4 watts of power.

Processor Power Management

To lower power consumption and heat generation, the 15-inch PowerBook G4 incorporates an automatic power management technique called dynamic frequency switching (DFS). DFS is designed to run at high processor speed and voltage when the demand on the processor is high, and to run at low processor speed and voltage when the demand on the processor is low. When DFS is enabled, the processor dynamically adjusts its speed based on the current needs of the system. Depending on the configuration, the processor speed will switch between 1500 MHz and 750 MHz or 1670 MHz and 835 MHz. The memory bus speed is not shifted.

Switching between different processor speeds and voltages is achieved by a transition that operates seamlessly to the user and should not impact system or application performance.

The 15-inch PowerBook G4 allows the user to control DFS mode. The options for specifying either high, reduced, or automatic processor and bus speeds are located at System Preferences>Energy Saver>Show Details>Options>Processor Performance; then select Highest, Automatic, or Reduced. DFS is enabled with the automatic setting, for processor performance.

If the 15-inch PowerBook G4 detects a system temperature that is high, due to high ambient temperatures or other factors, it will automatically force the system to reduce the speed regardless of the selected setting.

The 15-inch PowerBook G4 meets all applicable safety standards, including UL 60950 and IEC 60950.

Graphics Power Management

For additional power savings and reduced heat generation, the 15-inch PowerBook G4 incorporates a new graphics power management technique. When enabled, the graphics processor runs at a reduced voltage and slower clock rate, similar to DFS on the central processor. However, unlike DFS, the setting is static and does not automatically change as the load on the graphics processor changes.

Graphics power management is enabled by selecting reduced mode located at System Preferences>Energy Saver>Show Details> Options>Processor Perfomance.



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