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Leopard Technical Q&As
Apple provides information hardware developers can use to create products that are compatible with Macintosh computers and programming interfaces software developers can use to create software that drives or accesses devices.

A guided learning path for hardware and driver developers new to Mac OS X.   Essential information for developing drivers and device-access software.   API references organized by framework.
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Allocating and sharing memory with user space from an I/O Kit driver (HTML) (日本語 HTML)
QA1197: Describes the preferred technique for allocating and sharing buffers in an I/O Kit kernel driver.
AirPort/802.11 2008-10-13
ExpressCard Prevents System Sleep (HTML)
QA1517: Describes how some ExpressCard cards can prevent system sleep and how to fix the problem.
AirPort/802.11 2007-02-28
Generating a Non-Maskable Interrupt (NMI) (HTML) (日本語 HTML)
QA1264: Explains how to generate a non-maskable interrupt (NMI) on modern Macintosh systems.
AirPort/802.11 2008-10-13
Getting a Packet Trace (HTML) (日本語 HTML)
QA1176: Lists tools available for looking at the network packets on the wire.
AirPort/802.11 2008-06-03
Installing an I/O Kit KEXT Without Rebooting (HTML)
QA1319: Describes the state of the art of installing I/O Kit kernel extensions (KEXTs) without requiring a restart.
AirPort/802.11 2003-10-28
IODeviceTree and the I/O Registry (HTML) (日本語 HTML)
QA1120: Describes the IODeviceTree plane in the Mac OS X I/O Registry.
AirPort/802.11 2008-09-18
IOKit Framework Headers (HTML) (日本語 HTML)
QA1107: Describes the differences between the headers in IOKit.framework and the I/O Kit headers in Kernel.framework.
AirPort/802.11 2002-01-15
The "packages" node in the device tree (HTML)
HW90: Describes the "packages" node in the Open Firmware device tree.
AirPort/802.11 2006-02-22
Power Management; Policy Maker vs. Power Controller (HTML) (日本語 HTML)
QA1121: Describes the differences between a Power Management Policy Maker and a Power Management Power Controller.
AirPort/802.11 2002-02-13
What are configuration variables in Open Firmware? (HTML) (日本語 HTML)
HW38: Defines the configuration variables in Open Firmware.
AirPort/802.11 1999-02-15
128Mb SDRAM ICs limitation on original "Bronze Keyboard" Powerbook G3 (HTML)
QA1040: Outlines Memory ICs design limitation on original "Bronze Keyboard" Powerbook G3.
Apple Hardware 2001-06-21
The AAPL, slot-name property and PCI (HTML) (日本語 HTML)
HW61: Discusses the use of the AAPL,slot name property for PCI
Apple Hardware 1999-04-19
Are the Name Registry device tree nodes unique? (HTML)
Deprecated - HW64: Discusses whether Name Registry nodes copied from the Open Firmware device tree are unique.
Apple Hardware 1999-10-11
Bluetooth Radio Power Class for Apple Systems (HTML) (日本語 HTML)
QA1278: Notes Preferred Bluetooth Transmitter Characteristics for products designed for Apple Systems.
Apple Hardware 2003-08-06
Booting after invoking the Open Firmware user interface (HTML) (日本語 HTML)
HW48: Tells how to boot a system after entering the Open Firmware user interface.
Apple Hardware 1999-02-15
The "chosen" node in the device tree (HTML)
HW88: Describes how to find the "chosen" node in the Open firmware device tree.
Apple Hardware 2000-09-05
DDR SDRAM ICs for PowerBooks and iBooks that use Memory bus slewing (HTML)
QA1344: Specifies DDR SDRAM IC optimization for PowerBooks and iBooks that use Memory bus slewing.
Apple Hardware 2004-03-18
Detecting a CD-ROM (HTML) (日本語 HTML)
DV18: Demonstrates CD-ROM drive detection.
Apple Hardware 1997-01-31
Detecting specific ROM-in-RAM Mac (HTML) (日本語 HTML)
Deprecated - HW49: Identifying a Mac by name ("iMac"), and better alternatives for determining specific features ("has Firewire").
Apple Hardware 1999-10-05
Determining RAM size & location in New World Machines (HTML)
QA1065: Demonstrates Open Firmware method of determining RAM size & location in New World Machines.
Apple Hardware 2001-08-01
Determining the version of Open Firmware on your Mac (HTML) (日本語 HTML)
HW60: Describes a method to display the version of Open Firmware on a Macintosh.
Apple Hardware 1999-03-29
Difference between using Restart or Shut Down in the Finder's Special menu in Open Firmware (HTML) (日本語 HTML)
HW47: Explains the differences between using Restart or Shut Down on Open Firmware
Apple Hardware 1999-02-15
Disabling Processor Cores on a Multi-Core System (HTML) (日本語 HTML)
QA1141: Describes how to disable processor cores on a multi-core system for testing purposes.
Apple Hardware 2008-09-16
Displaying PCI Configuration Registers contents in Open Firmware (HTML)
QA1036: Demonstrates how to display PCI Configuration Resister contents in Open Firmware.
Apple Hardware 2001-05-18
dl command in 1 machine mode (HTML) (日本語 HTML)
HW51: Describes using the "dl" command in 1 machine mode.
Apple Hardware 1999-03-29
Do PowerBooks have a PCI bus? (HTML) (日本語 HTML)
HW43: Explains that a Powerbook has a PCI bus.
Apple Hardware 1999-02-15
DR Emulator Caches (HTML) (日本語 HTML)
Deprecated - HW28: Describes the Dynamic Recompiling emulator's cache, including a description of when to flush the cache.
Apple Hardware 1996-04-08
DRAM DIMM power pin connections for Macintosh Computers (HTML) (日本語 HTML)
QA1271: Discusses design considerations for DRAM DIMM power pin connections for Macintosh Computers.
Apple Hardware 2003-07-04
Empty Memory Objects (HTML) (日本語 HTML)
QA1259: Describes how two memory management edge cases are handled by the common Mac OS memory allocators.
Apple Hardware 2003-04-21
Energy Star PCI Device (HTML) (日本語 HTML)
QA1108: Provides useful information for developers of Energy Star-compliant PCI devices.
Apple Hardware 2002-01-15
Explanation of SDRAM configuration Nomenclature (HTML)
HW75: Explains the three-part "Device configuration" numbers for SDRAM in the Power Mac G4 Computer Developer Note.
Apple Hardware 1999-10-18
Faster DDR DRAM in the 867MHz Power Mac G4 (Mirrored Drive Doors) (HTML) (日本語 HTML)
QA1191: Confirms the use of faster DDR DRAM in the 867MHz Power Mac G4 (Mirrored Drive Doors).
Apple Hardware 2002-08-19
Generating a Non-Maskable Interrupt (NMI) (HTML) (日本語 HTML)
QA1264: Explains how to generate a non-maskable interrupt (NMI) on modern Macintosh systems.
Apple Hardware 2008-10-13
The "green" PCI bus (HTML)
HW93: Explains why the PCI bus is considered "green".
Apple Hardware 2000-09-05
How do I change the numeric base for the Open Firmware user interface? (HTML)
HW66: Explains how to change the numeric base for the Open Firmware user interface.
Apple Hardware 1999-10-11
How do I determine the top of the Open Firmware dictionary? (HTML)
HW69: Explains how to determine the top of the Open Firmware dictionary.
Apple Hardware 1999-10-11
How does Open Firmware generate the name property? (HTML) (日本語 HTML)
HW39: Describes the Open Firmware name property generation process.
Apple Hardware 1999-02-15
Installing an I/O Kit KEXT Without Rebooting (HTML)
QA1319: Describes the state of the art of installing I/O Kit kernel extensions (KEXTs) without requiring a restart.
Apple Hardware 2003-10-28
Invoking the Open Firmware user interface (HTML) (日本語 HTML)
HW45: Describes how to invoke the Open Firmware user interface on startup.
Apple Hardware 1999-02-15
IODeviceTree and the I/O Registry (HTML) (日本語 HTML)
QA1120: Describes the IODeviceTree plane in the Mac OS X I/O Registry.
Apple Hardware 2008-09-18
IOKit Framework Headers (HTML) (日本語 HTML)
QA1107: Describes the differences between the headers in IOKit.framework and the I/O Kit headers in Kernel.framework.
Apple Hardware 2002-01-15
Maximum Memory for the "Firewire" PowerBook (HTML)
Deprecated - HW83: Discrepancies between PowerBook Developer Note and TIL articles 14870 and 58582, regarding maximum memory configurations.
Apple Hardware 2000-03-13
Menu Bar Clock and NVRAM (HTML)
QA1102: Explains why booting with the Command-Option-P-R keys doesn't reset date and time preferences.
Apple Hardware 2001-12-21
Open Firmware device tree nodes (HTML)
HW86: Explains the usage of the "@n" notation in Open Firmware device tree nodes.
Apple Hardware 2000-09-05
Open Firmware Memory bus speed (HTML)
HW97: Describes a method to display memory bus speed for G3 or G4 Macintosh in Open Firmware.
Apple Hardware 2000-09-22
Open Firmware version number (HTML)
HW96: Discusses the unique values of Open Firmware version numbers.
Apple Hardware 2000-09-22
OTScheduleDeferredTask When Task Running (HTML) (日本語 HTML)
NW52: Describes what happens when you use OTScheduleDefferedTask to schedule a task that is running.
Apple Hardware 1997-10-13
The "packages" node in the device tree (HTML)
HW90: Describes the "packages" node in the Open Firmware device tree.
Apple Hardware 2006-02-22
PC100 SDRAM DIMMs on the Flat Panel iMac (HTML) (日本語 HTML)
QA1130: Describes PC100 SDRAM DIMM limitations on the "original " Flat Panel iMac.
Apple Hardware 2002-03-18
PCI bus on the iMac (HTML) (日本語 HTML)
HW42: Explains that the iMac has a PCI bus even though it has no expansion slots.
Apple Hardware 1999-02-15
PCI class codes (HTML)
HW91: Explains why PCI class codes are important.
Apple Hardware 2000-09-05
PCI Header types (HTML)
HW78: Describes the three required types of PCI headers to be provided in its configuration header space.
Apple Hardware 1999-11-15
PCI Macintoshes and CardBus controllers (HTML)
HW87: Explains why older PCI Macintoshes do not recognize a Cardbus controller.
Apple Hardware 2000-09-05
Power adapter Sensing for the 17" PowerBook (HTML) (日本語 HTML)
QA1266: Details Design and detection considerations for 17-inch PowerBook power adapters
Apple Hardware 2003-06-12
Power Management; Policy Maker vs. Power Controller (HTML) (日本語 HTML)
QA1121: Describes the differences between a Power Management Policy Maker and a Power Management Power Controller.
Apple Hardware 2002-02-13
PrepareMemoryForIO in the NewWorld (HTML)
DV33: Explains the correct use of PrepareMemoryForIO on DMA buffers when writing a device driver for DMA software.
Apple Hardware 1998-12-07
Programmatically causing restart, shutdown and/or logout (HTML) (日本語 HTML)
QA1134: Describes how to programmatically cause restart, shutdown, sleep or logout.
Apple Hardware 2008-09-24
Reducing the size of Physical Memory in Open Firmware (HTML)
QA1099: Describes how to configure the Power Macintosh so less memory is recognized than is actually present.
Apple Hardware 2001-12-20
Resetting NVRAM to factory defaults (HTML)
QA1103: Describes what happens when you boot holding the Command-Option-P-R keys.
Apple Hardware 2001-12-21
A SCSI little secret (HTML)
HW81: Details what to expect when accessing the motherboard SCSI bus on the Blue & White G3.
Apple Hardware 1999-12-20
SDRAM Problems With Self-Powered USB Devices (HTML) (日本語 HTML)
HW82: Alerts that non-compliant, self-powered USB devices plugged into a G4, can cause problems with low-voltage-sensitive SDRAM .
Apple Hardware 2003-08-21
SDRAM, CAS Latency for the (HTML)
QA1071: Describes the supported CAS Latency values for the "QuickSilver", PowerMac G4 CPUs.
Apple Hardware 2001-09-13
Sleep vs. Doze on Mac OS X (HTML)
QA1309: Discusses and demonstrates sleep versus doze detection on Machintosh Mac OS X
Apple Hardware 2003-10-09
Stopping Forth command scrolls (HTML) (日本語 HTML)
HW57: Describes how to limit Forth commands from scrolling off the screen.
Apple Hardware 1999-03-29
What are configuration variables in Open Firmware? (HTML) (日本語 HTML)
HW38: Defines the configuration variables in Open Firmware.
Apple Hardware 1999-02-15
What are snag keys in Open Firmware? (HTML) (日本語 HTML)
HW35: Explains Open Firmware snag keys, including examples of their function.
Apple Hardware 1999-02-15
What is meant by 1 machine mode vs. 2 machine mode with respect to Open Firmware? (HTML) (日本語 HTML)
HW36: Documents 1 machine mode vs. 2 machine mode in Open Firmware.
Apple Hardware 1999-02-15
What is the word "see" and how do I use it to help me find what a word does? (HTML)
HW72: Explains the function and use of the Open Firmware word "see".
Apple Hardware 1999-10-11
Which Machines Support Driver Services Library and the MP Nanokernel? (HTML) (日本語 HTML)
HW63: Lists the systems that do and don't support the Driver Services Library and the MP Nanokernel.
Apple Hardware 1999-07-12
Working with Configuration Variables (HTML) (日本語 HTML)
QA1119: Explains how to delete a specific Open Firmware configuration variable without using Command-Option-P-R.
Apple Hardware 2002-02-13
Allocating and sharing memory with user space from an I/O Kit driver (HTML) (日本語 HTML)
QA1197: Describes the preferred technique for allocating and sharing buffers in an I/O Kit kernel driver.
ATA 2008-10-13
Detecting a CD-ROM (HTML) (日本語 HTML)
DV18: Demonstrates CD-ROM drive detection.
ATA 1997-01-31
The dreaded "incompatible flag -framework" error (HTML)
QA1096: Explains how to eliminate the incompatible flag -framework error in Project Builder.
ATA 2001-12-05
ExpressCard Prevents System Sleep (HTML)
QA1517: Describes how some ExpressCard cards can prevent system sleep and how to fix the problem.
ATA 2007-02-28
Generating a Non-Maskable Interrupt (NMI) (HTML) (日本語 HTML)
QA1264: Explains how to generate a non-maskable interrupt (NMI) on modern Macintosh systems.
ATA 2008-10-13
Getting a List of Drivers & LUNs (logical unit numbers) (HTML)
Deprecated - DV04: Describes a legacy Mac OS technique for obtaining a list of SCSI Parallel drivers, devices, and LUNs.
ATA 1995-07-01
Installing an I/O Kit KEXT Without Rebooting (HTML)
QA1319: Describes the state of the art of installing I/O Kit kernel extensions (KEXTs) without requiring a restart.
ATA 2003-10-28
IODeviceTree and the I/O Registry (HTML) (日本語 HTML)
QA1120: Describes the IODeviceTree plane in the Mac OS X I/O Registry.
ATA 2008-09-18
IOKit Framework Headers (HTML) (日本語 HTML)
QA1107: Describes the differences between the headers in IOKit.framework and the I/O Kit headers in Kernel.framework.
ATA 2002-01-15
Issues with boot time KEXT loading (HTML) (日本語 HTML)
QA1087: Explains how to solve problems with loading KEXTs at boot time.
ATA 2004-01-15
Legacy Devices (HTML)
HW84: Discusses why legacy devices with hard-wired I/O addresses may not work properly with Open Firmware.
ATA 2000-03-20
Making sense of IOKit error codes (HTML) (日本語 HTML)
QA1075: Explains how to interpret I/O Kit error codes.
ATA 2002-02-07
The "packages" node in the device tree (HTML)
HW90: Describes the "packages" node in the Open Firmware device tree.
ATA 2006-02-22
Power Management; Policy Maker vs. Power Controller (HTML) (日本語 HTML)
QA1121: Describes the differences between a Power Management Policy Maker and a Power Management Power Controller.
ATA 2002-02-13
Allocating and sharing memory with user space from an I/O Kit driver (HTML) (日本語 HTML)
QA1197: Describes the preferred technique for allocating and sharing buffers in an I/O Kit kernel driver.
Audio 2008-10-13
Are the Name Registry device tree nodes unique? (HTML)
Deprecated - HW64: Discusses whether Name Registry nodes copied from the Open Firmware device tree are unique.
Audio 1999-10-11
Available FireWire Isochronous Bandwidth (HTML)
QA1356: Discusses attempting to "pre-flight" an isochronous bandwidth allocation request by reading the currently available bandwidth.
Audio 2004-07-07
Generating a Non-Maskable Interrupt (NMI) (HTML) (日本語 HTML)
QA1264: Explains how to generate a non-maskable interrupt (NMI) on modern Macintosh systems.
Audio 2008-10-13
Installing an I/O Kit KEXT Without Rebooting (HTML)
QA1319: Describes the state of the art of installing I/O Kit kernel extensions (KEXTs) without requiring a restart.
Audio 2003-10-28
IODeviceTree and the I/O Registry (HTML) (日本語 HTML)
QA1120: Describes the IODeviceTree plane in the Mac OS X I/O Registry.
Audio 2008-09-18
IOKit Framework Headers (HTML) (日本語 HTML)
QA1107: Describes the differences between the headers in IOKit.framework and the I/O Kit headers in Kernel.framework.
Audio 2002-01-15
Obtaining the name of an external MIDI Device from a MIDI Endpoint (HTML)
QA1374: Get the names of external MIDI Devices from MIDI Endpoints.
Audio 2004-12-01
The "packages" node in the device tree (HTML)
HW90: Describes the "packages" node in the Open Firmware device tree.
Audio 2006-02-22
Power Management; Policy Maker vs. Power Controller (HTML) (日本語 HTML)
QA1121: Describes the differences between a Power Management Policy Maker and a Power Management Power Controller.
Audio 2002-02-13
Retain Counts of io_object_t Objects in IOKit.framework (HTML) (日本語 HTML)
QA1195: Distinguishes between the retain counts of an I/O Kit kernel object and its io_object_t user space proxy.
Audio 2008-09-24
What are configuration variables in Open Firmware? (HTML) (日本語 HTML)
HW38: Defines the configuration variables in Open Firmware.
Audio 1999-02-15
Allocating and sharing memory with user space from an I/O Kit driver (HTML) (日本語 HTML)
QA1197: Describes the preferred technique for allocating and sharing buffers in an I/O Kit kernel driver.
Bluetooth 2008-10-13
Bluetooth Radio Power Class for Apple Systems (HTML) (日本語 HTML)
QA1278: Notes Preferred Bluetooth Transmitter Characteristics for products designed for Apple Systems.
Bluetooth 2003-08-06
Generating a Non-Maskable Interrupt (NMI) (HTML) (日本語 HTML)
QA1264: Explains how to generate a non-maskable interrupt (NMI) on modern Macintosh systems.
Bluetooth 2008-10-13
Installing an I/O Kit KEXT Without Rebooting (HTML)
QA1319: Describes the state of the art of installing I/O Kit kernel extensions (KEXTs) without requiring a restart.
Bluetooth 2003-10-28