Jump To:
Technical Q&As: Hardware
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.

View all Performance Technical Q&As.
Document Descriptions
On Off
Display

Sort by
Title
Sorted by
Date
Generating an NMI Without a Programmer's Switch (HTML) ()
QA1264: Explains how to generate a non-maskable interrupt (NMI) on CPUs without programmer's switches.
2004-04-26
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.
2003-10-28
Sleep vs. Doze on Mac OS X (HTML)
QA1309: Discusses and demonstrates sleep versus doze detection on Machintosh Mac OS X
2003-10-09
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.
2003-09-24
SDRAM Problems With Self-Powered USB Devices (HTML) ()
HW82: Alerts that non-compliant, self-powered USB devices plugged into a G4, can cause problems with low-voltage-sensitive SDRAM .
2003-08-21
Bluetooth Radio Power Class for Apple Systems (HTML) ()
QA1278: Notes Preferred Bluetooth Transmitter Characteristics for products designed for Apple Systems.
2003-08-06
DRAM DIMM power pin connections for Macintosh Computers (HTML) ()
QA1271: Discusses design considerations for DRAM DIMM power pin connections for Macintosh Computers.
2003-07-04
Power adapter Sensing for the 17" PowerBook (HTML) ()
QA1266: Details Design and detection considerations for 17-inch PowerBook power adapters
2003-06-12
Empty Memory Objects (HTML) ()
QA1259: Describes how two memory management edge cases are handled by the common Mac OS memory allocators.
2003-04-21
Faster DDR DRAM in the 867MHz Power Mac G4 (Mirrored Drive Doors) (HTML) ()
QA1191: Confirms the use of faster DDR DRAM in the 867MHz Power Mac G4 (Mirrored Drive Doors).
2002-08-19
Disabling a Processor on a Multiprocessor System (HTML) ()
QA1141: Describes how to disable a processor on a multiprocessor system for testing purposes.
2002-05-22
PC100 SDRAM DIMMs on the Flat Panel iMac (HTML) ()
QA1130: Describes PC100 SDRAM DIMM limitations on the "original " Flat Panel iMac.
2002-03-18
Energy Star PCI Device (HTML) ()
QA1108: Provides useful information for developers of Energy Star-compliant PCI devices.
2002-01-15
IOKit Framework Headers (HTML) ()
QA1107: Describes the differences between the headers in IOKit.framework and the I/O Kit headers in Kernel.framework.
2002-01-15
Menu Bar Clock and NVRAM (HTML)
QA1102: Explains why booting with the Command-Option-P-R keys doesn't reset date and time preferences.
2001-12-21
PCI Bus? (HTML)
QA1104: Answers the question, "Do all Macintosh computers have a PCI bus?"
2001-12-21
Resetting NVRAM to factory defaults (HTML)
QA1103: Describes what happens when you boot holding the Command-Option-P-R keys.
2001-12-21
SDRAM, CAS Latency for the "Quicksilver" PowerMacG4s (HTML)
QA1071: Describes the supported CAS Latency values for the "QuickSilver", PowerMac G4 CPUs.
2001-09-13
Determining RAM size & location in New World Machines (HTML)
QA1065: Demonstrates Open Firmware method of determining RAM size & location in New World Machines.
2001-08-01
Displaying PCI Configuration Registers contents in Open Firmware (HTML)
QA1036: Demonstrates how to display PCI Configuration Resister contents in Open Firmware.
2001-05-18
Open Firmware version number (HTML)
HW96: Discusses the unique values of Open Firmware version numbers.
2000-09-22
The "packages" node in the device tree (HTML)
HW90: Describes the "packages" node in the Open Firmware device tree.
2000-09-05
PCI class codes (HTML)
HW91: Explains why PCI class codes are important.
2000-09-05
PCI Macintoshes and CardBus controllers (HTML)
HW87: Explains why older PCI Macintoshes do not recognize a Cardbus controller.
2000-09-05
A SCSI little secret (HTML)
HW81: Details what to expect when accessing the motherboard SCSI bus on the Blue & White G3.
1999-12-20
Is the Open Firmware device tree object oriented? (HTML)
HW80: Discusses the object-oriented attributes of the Open Firmware device tree.
1999-11-15
PCI Header types (HTML)
HW78: Describes the three required types of PCI headers to be provided in its configuration header space.
1999-11-15
Explanation of SDRAM configuration Nomenclature (HTML)
HW75: Explains the three-part "Device configuration" numbers for SDRAM in the Power Mac G4 Computer Developer Note.
1999-10-18
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.
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.
1999-10-11
Sample code for allocating an amount of dictionary space (HTML)
HW71: Discusses the allocation and the setting of memory for Dictionary space in Open Firmware.
1999-10-11
What is the "dump" word and how do I use it? (HTML)
HW68: Describes the function of the Open Firmware word "dump" and how it can be used.
1999-10-11
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".
1999-10-11
What numeric base is the default for the Open Firmware user interface? (HTML)
HW65: Describes how the default numeric base used by the Open Firmware user interface is hexadecimal.
1999-10-11
Which Machines Support Driver Services Library and the MP Nanokernel? (HTML) ()
HW63: Lists the systems that do and don't support the Driver Services Library and the MP Nanokernel.
1999-07-12
Determining Open Firmware configuration variables (HTML) ()
HW56: Discusses how to determine the Open Firmware variables on a system.
1999-03-29
Determining the version of Open Firmware on your Mac (HTML) ()
HW60: Describes a method to display the version of Open Firmware on a Macintosh.
1999-03-29
Getting started with Forth (HTML) ()
HW53: Describes where FCode driver developers can get information about the Forth programming language.
1999-03-29
Stopping Forth command scrolls (HTML) ()
HW57: Describes how to limit Forth commands from scrolling off the screen.
1999-03-29
Why did the name of the PCI bridge change? (HTML) ()
HW59: Explains the name change of the PCI bridge to the generic name "pci" in Open Firmware.
1999-03-29
Are interrupts enabled while Open Firmware is running? (HTML) ()
HW44: Explains that interrupts are disabled when Open Firmware is running.
1999-02-15
OTScheduleDeferredTask When Task Running (HTML) ()
NW52: Describes what happens when you use OTScheduleDefferedTask to schedule a task that is running.
1997-10-13