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Leopard Technical Q&As: Hardware & Drivers
Apple provides tools, technologies, and programming interfaces to measure, evaluate, and optimize performance. Developers can use these tools to improve the performance of hardware devices and software.

View all Performance Technical Q&As.
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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.
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.
The "packages" node in the device tree (HTML)
HW90: Describes the "packages" node in the Open Firmware device tree.
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.
Sleep vs. Doze on Mac OS X (HTML)
QA1309: Discusses and demonstrates sleep versus doze detection on Machintosh Mac OS X
How can I tell if a PCI device has on board I/O space? (HTML)
QA1287: Demonstrates "how to" tell if a PCI device has on board I/O space.
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 .
Bluetooth Radio Power Class for Apple Systems (HTML) (日本語 HTML)
QA1278: Notes Preferred Bluetooth Transmitter Characteristics for products designed for Apple Systems.
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.
Power adapter Sensing for the 17" PowerBook (HTML) (日本語 HTML)
QA1266: Details Design and detection considerations for 17-inch PowerBook power adapters
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.
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).
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.
Energy Star PCI Device (HTML) (日本語 HTML)
QA1108: Provides useful information for developers of Energy Star-compliant PCI devices.
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.
Menu Bar Clock and NVRAM (HTML)
QA1102: Explains why booting with the Command-Option-P-R keys doesn't reset date and time preferences.
Resetting NVRAM to factory defaults (HTML)
QA1103: Describes what happens when you boot holding the Command-Option-P-R keys.
SDRAM, CAS Latency for the (HTML)
QA1071: Describes the supported CAS Latency values for the "QuickSilver", PowerMac G4 CPUs.
Determining RAM size & location in New World Machines (HTML)
QA1065: Demonstrates Open Firmware method of determining RAM size & location in New World Machines.
Displaying PCI Configuration Registers contents in Open Firmware (HTML)
QA1036: Demonstrates how to display PCI Configuration Resister contents in Open Firmware.
Open Firmware version number (HTML)
HW96: Discusses the unique values of Open Firmware version numbers.
PCI class codes (HTML)
HW91: Explains why PCI class codes are important.
PCI Macintoshes and CardBus controllers (HTML)
HW87: Explains why older PCI Macintoshes do not recognize a Cardbus controller.
A SCSI little secret (HTML)
HW81: Details what to expect when accessing the motherboard SCSI bus on the Blue & White G3.
PCI Header types (HTML)
HW78: Describes the three required types of PCI headers to be provided in its configuration header space.
Explanation of SDRAM configuration Nomenclature (HTML)
HW75: Explains the three-part "Device configuration" numbers for SDRAM in the Power Mac G4 Computer Developer Note.
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.
How do I determine the top of the Open Firmware dictionary? (HTML)
HW69: Explains how to determine the top of the Open Firmware dictionary.
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".
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.
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.
Stopping Forth command scrolls (HTML) (日本語 HTML)
HW57: Describes how to limit Forth commands from scrolling off the screen.
OTScheduleDeferredTask When Task Running (HTML) (日本語 HTML)
NW52: Describes what happens when you use OTScheduleDefferedTask to schedule a task that is running.