Mac OS X Reference Library Drivers, Kernel, & Hardware: User-Space Device Access Accessing Hardware From ApplicationsComputer hardware, typically excluding the CPU and system memory, that can be controlled and can send or receive data. Examples of devices include monitors, drives, bus controllers, and keyboards.
A special file the I/O Kit creates in the /dev directory for each serial and storage device it discovers.
A plug-in interface, provided by an I/O Kit family, that conforms to the CFPlugIn architecture. Code running on Mac OS X can call the functions in a device interface to access the in-kernel object representing a device. A device interface transmits an application’s commands to the device object via a user client. See also user client.
The I/O Kit process of searching the I/O Registry for objects representing one or more specific kinds of device.
A unit of software that manages a specific piece of hardware. A driver written with the I/O Kit is an object that implements the appropriate I/O Kit abstractions for controlling that hardware.
A driver can serve as a nub, but this is rare. See also nub.
The I/O Kit process of locating a suitable driver for a device.
A dictionary of key/value pairs that specify device property values, such as family type, vendor name, or product name. A driver is suitable for any device whose properties match one of the driver’s personalities.
A collection of software abstractions that are common to all devices of a particular category. Families provide functionality and services to drivers. The I/O Kit defines families for bus protocols (such as SCSI, USB, and FireWire), storage devices, human interface devices, and many others.
A type of bundle that packages a dynamic shared library with the resources the library requires, including header files and reference documentation.
An object-oriented framework for developing device drivers on Mac OS X. The I/O Kit provides many features, from a set of object classes that model system software and streamline the task of writing device drivers, to a dynamic model for identifying, loading, and unloading drivers and other services in a running system.
The framework that includes IOKitLib.h and makes the I/O Registry, user client plug-ins, and other I/O Kit services available to applications and other code. Stored on disk as IOKit.framework.
A dynamic database that describes a collection of ”live” objects, each of which represents an I/O Kit entity, such as a family, driver, or nub. As hardware is added to or removed from the system, the I/O Registry is modified to reflect the changes.
The protected memory partition in which the kernel resides. See also user space.
A dictionary of key/value pairs that describe the properties of a device or other service. The values in a matching dictionary are compared against those in a driver personality during device matching.
An I/O Kit object that represents a detected, controllable entity, such as a device or logical service. A nub may represent a bus controller, a disk, a graphics adaptor, or any number of similar entities. When it supports a specific piece of hardware, a nub is also a driver (although this is rare).
A nub supports dynamic configuration by providing a connection match point between two drivers (and, by extension, between two families). A nub can also provide services to code running in user space through a device interface. See also driver.
An object module that can be dynamically added to a running system or application.
Core Foundation Plug-in Services uses the basic code-loading facility of Core Foundation Bundle Services to provide a standard plug-in architecture, known as the Core Foundation plug-in model, for Mac OS X applications.
A specification, approved as ANSI standard X3.270-1996, that defines a common interface standard between computers and devices such as disk drives, printers, and scanners.
An industry standard parallel data bus that provides a consistent method of connecting computers and peripheral devices.
A service is an I/O Kit entity, based on a subclass of IOService, that has been published with the registerService method and provides certain capabilities to other I/O Kit objects. In the I/O Kit’s layered architecture, each layer is a client of the layer below it and a provider of services to the layer above it.
An in-kernel object that inherits from the IOService class and provides a connection between an in-kernel device driver or device nub and an application or process in user space. See also device interface.
Memory outside the protected partition in which the kernel resides. Applications, plug-ins, and other types of modules typically run in user space. See also kernel space.
© 2001, 2007 Apple Inc. All Rights Reserved. (Last updated: 2007-02-08)
Mac OS X Reference Library Drivers, Kernel, & Hardware: User-Space Device Access Accessing Hardware From Applications