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Leopard Technical Q&As: Audio
Core Audio's Hardware Abstraction Layer (HAL) acts as the interface between an audio device driver and an audio application. The HAL supports native multichannel audio in a manner that is scalable to future high-resolution formats. Developers can create audio devices compatible with Apple products and use HAL and I/O Kit APIs to create software to access audio devices.

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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.
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.
2004-07-07
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
1999-02-15
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.
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.
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.
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.
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.
2004-12-01
The "packages" node in the device tree (HTML)
HW90: Describes the "packages" node in the Open Firmware device tree.
2006-02-22
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.
2008-09-24
Unable to select input device in AU Lab (HTML)
QA1526: AU Lab only supports physical device singletons.
2007-05-17
When to use PCMCIA, PC Card, and CardBus (HTML)
HW77: Explains the differences between PCMCIA, PC Card, and CardBus.
1999-11-15