CD-DA:(Compact Disc-Digital Audio) An optical data-storage format that provides for the storage of up to 73 minutes of high-quality digital-audio data on a compact disc. Also known as Red Book audio.
CD-ROM:(Compact Disc-Read Only Memory) An optical data-storage technology that allows large quantities of data to be stored on a compact disc.
CD-XA:(CD-ROM Extended Architecture) An extension of the CD-ROM standard that provides for storage of compressed audio data along with other data on a CD-ROM disc. This standard also defines the way data is read from a disc. Audio signals are combined with text and graphic data on a single track so they can be read at virtually the same time.
channel:MIDI provides a way to send messages to an individual device within a MIDI setup. There are 16 MIDI channel numbers. Devices in a MIDI setup can be directed to respond only to messages marked with a channel number specific to the de-vice.
channel map:The MIDI Mapper provides a channel map that can redirect MIDI messages from one channel to another.
character code:A value that represents a particular character in a set, such as the ASCII character set.
chunk:The basic building block of a RIFF file, consisting of an identifier (called a chunk ID), a chunk-size variable, and a chunk data area of variable size.
class menu:The default menu for a window class. All windows of a given class use the same menu unless the application specifies a different menu when creating a window of that class.
client:In the context of mailslots, a process that writes a message to a mailslot.
CMY format:A color format that identifies a given color with a (cyan, magenta, yellow) triplet. This format is used by printers and other ink-based devices.
coherent:A description of file views that contain identical data at a given time. File views are coherent if they are derived from the same file mapping object.
color plane:An array of bits that represents the red, green, blue, or intensity components for the pixels in a bitmapped image.
command item:A menu item that, when chosen, sends a command message to the window procedure of the window that owns the menu.
command message:In MCI, a command message is a symbolic constant that represents a unique command for an MCI device. Command messages have associated data structures that provide information a device requires to carry out a request.
command string:In MCI, a command string is a null-terminated character string that represents a command for an MCI device. The text string contains all the information that an MCI device needs to carry out a request. MCI parses the text string and translates it into an equivalent command message and data structure that it then sends to a MCI device driver.
comment:A string of text that is inserted between records in a metafile.
compatible DC:A virtual-device context that provides a means of storing an image which was created on a physical display. (Compatible DCs are sometimes referred to as “memory” DCs.)
compound device:An MCI device that requires a device element, usually a data file. An example of a compound device is the MCI waveform-audio driver.
compound file:A number of individual files bound together in one physical file. Each individual file in a compound file can be accessed as if it were a single physical file.
context switch:When the scheduler suspends the execution of one thread so another thread can execute, it saves the context —the machine state: registers, stacks, etc.—of the suspended thread and restores the saved context of the thread to be executed.
control change:See MIDI control-change message.
coordinate space:A planar space based on the Cartesian system. This system requires two axis which are perpendicular and equal in length. There are four coordinate spaces in Windows: world, page, device, and client area (or desktop, or page of printer paper).
cosmetic pen:A pen with dimensions that are specified in device units (or pixels).
current position:The starting point for any line- or curve-drawing operations.
custom resource:See user-defined resource.