d

D

DAC

See: digital-to-analog convertor (DAC)

daisy chain: A chain of any number of patches and one system software routine.

dangling pointer: A pointer that no longer points to the correct memory address.

dangling reference: Typically, a pointer whose target has been either destroyed or moved elsewhere in memory.

dash: Applying a dash shape to the contours of another shape

See also: dash property

dashed shape: A shape whose contours have been drawn with a dash shape.

dash advance: The distance between dashes in a dashed contour.

dash attributes: A set of flags that modify the way QuickDraw GX dashes a shape.

dash phase: How far into a dash a contour begins.

dash property: A property of the style object used to draw contours as repeated patterns of shapes rather than continues lines.

dash scale: The factor to divide by when scaling a dash shape perpendicularly to the dashed shape's contours.

dash shape: A shape used to dash the contours of another shape.

database extension: The interface between the Data Access Manager and a data server.

datagram

See: packet

Datagram Delivery Protocol (DDP): A connectionless AppleTalk protocol that provides best-effort delivery. DDP, which is implemented at the network level, transfers datagrams between sockets over an AppleTalk internet with each packet carrying its destination internet socket address

See also: packet

datagram network

See: connectionless network

data attribute: In a dictionary, some information about raw data"for example, grammatical or context-sensitive details.

data buffer: A buffer (usually in an application's heap) that contains information to be written to a file from the application, or read from a file to an application.

data cache: An area of memory internal to some microprocessors (for example, the MC68030 and MC68040 microprocessors) that holds recently accessed data

See also: instruction cache

data communication equipment (DCE): Any device connected to the serial port, such as a modem or printer.

data dependency: An aspect of image compression in which compression ratios are highly dependent on the image content. Using an algorithm with a high degree of data dependency, an image of a crowd at a football game (which contains a lot of detail) may produce a very small compression ratio, whereas an image of a blue sky (which consists mostly of constant colors and intensities) may produce a very high compression ratio.

Data Encryption Standard (DES): A standard algorithm for data encryption.

data fork: One of two forks of a Macintosh file. The data fork can contain text, code, or data, or it can be empty. PowerPC runtime fragments and CFM-68K shared library fragments are stored in the data fork

See also: resource fork

data handler: A piece of software that is responsible for reading and writing a media's data. The data handler provides data input and output services to the media's media handler.

data phase: The phase in which data transfer takes place between a SCSI initiator and target.

data reference: A reference to a media's data.

data section: The part of a fragment that contains the static data used by the code section. A fragment may contain multiple data sections

See also: code section

data server: An application that acts as an interface between a database extension on a Macintosh computer and a data source, which can be on the Macintosh computer or on a remote host computer. A data server can be a database server program that can provide an interface to a variety of different databases, or it can be the data source itself, such as a Macintosh application.

data stream: A highly structured sequence of bytes that contains all of the information required to store, print, or display QuickDraw GX objects.

data terminal equipment (DTE): The initiator or controller of a serial data connection, typically the computer.

date cache: A temporary storage area used to convert strings to date and time values.

date-time record: A data structure that represents date and time as a record rather than a 32-bit long integer. The date-time record is a translation of the standard date-time value, so it can represent only dates and times between midnight on January 1, 1904 and 6:28:15 A.M. on February 6, 2040.

DCE

See: data communication equipment (DCE), device control entry (DCE)

DDP

See: Datagram Delivery Protocol (DDP)

dead cache: A shape cache that is out of date. The object or environment associated with the cache has been changed since the cache was created.

dead key: A keypress or modifier-plus-keypress combination that produces no immediate effect, but instead affects the character or characters produced by the next key (called the completer key) that is pressed. For example, in the U.S. Roman system Option-E has no effect; however, when you type e after pressing Option-E, the accented form appears: _.

debugging environment: The QuickDraw GX application development environment consisting of the debugging version; errors, warnings, and notices; application-defined message handlers; the drawing errors; validation function; and the MacsBug and GraphicsBug utilities

See also: error, message handler, notice, warning

debugging version: The version of QuickDraw GX that provides validation and an extended set of errors, warnings, and notices. This version is intended for use during application development

See also: error, non-debugging version, notice, warning

decimal format structure: A data type for specifying the formatting for decimal (base 10) numbers (of conversions). It specifies the decimal number's style and number of digits. It is defined by the decform data type.

decimal structure: A data type for storing decimal data. It consists of three fields: sign, exponent, and significand (a C string). It is defined by the decimal data type.

declaration ROM: A ROM on a NuBus expansion card that contains information identifying the card and its functions, and that may also contain code or other data. Proper configuration of the declaration ROM firmware will allow the card to communicate with the computer through the Slot Manager routines.

decompressed sound data: Sampled-sound data that has been subjected to audio compression and expansion.

decompression

See: audio expansion

decrypt: To restore encrypted data to its previous, legible (unscrambled) state. In most cryptographic systems, decryption is performed by mathematically manipulating the data with a large number called a key.

default ADB device address: A 4-bit bus address between $0 and $E that uniquely identifies the general type of ADB device (such as a mouse or keyboard).

default attributes: The attributes that determines the initial attribute values assigned to items added to a collection.

default button: In an alert or dialog box, the button whose action is invoked if the user presses the Return key or the Enter key. The Appearance Manager identifies the default button by drawing a ring around it. The default button should invoke the preferred action which, whenever possible, should be a 'safe' action _ that is, one that doesn't cause loss of data

See also: action button

default CMM: A CMM supplied by Apple Computer, Inc. and Linotype-Hell that supports all the required and optional functions defined by the ColorSync Manager, and is therefore a suitable CMM of last resort when a specified CMM is not available or cannot perform a specified operation

See also: preferred CMM

default container: The outermost container in an application's container hierarchy; usually the application itself

See also: container hierarchy

default directory: The directory used in File Manager routines whenever you don't explicitly specify some directory

See also: current directory

default environment: The environment settings when a PowerPC Numerics implementation starts up: rounding is to nearest and all exception flags are clear.

default implementation: The implementation of a printing message that is provided by QuickDraw GX. This is the code that executes if your printing extension or printer driver does not totally override the message.

default location: The folder or volume whose contents are displayed in the browser list when a dialog box is first opened.

default memory size: The implementation limit size of the graphic client memory heap that QuickDraw GX will select if the memory size is not specified.

default object: (1) For most kinds of objects, an object with the properties of a newly created object. When it creates an object, QuickDraw GX assigns it the default properties for that kind of object; an application may then alter those properties through accessor functions. (2) For color sets, the color set to assign as the default to a bitmap shape of a given pixel depth. (3) For color profiles, the profile to use for color matching when no profile is specified.

default operating system: The operating system that gets initialized and booted on a Macintosh computer. Currently, the only default operating system allowed is the Mac OS.

default scripting component: The scripting component used by the generic scripting component when an application passes kOSANullScript rather than a valid script ID to OSACompile or OSAStartRecording.

default startup device: The first drive on which the boot code attempts to start up the Mac OS.

default system profile: The system profile that serves as the default display profile, as well as the default profile for color conversion and matching operations for which no profile is specified. Unless the ColorSync Manager control panel is used to select a different profile, which must be an RGB profile, ColorSync uses the Apple 13-inch color display

default video device: The first monitor on which the system displays the startup message 'Welcome to Macintosh.' and other startup indications.

default volume: The volume that contains the default directory.

defer: To postpone the execution of an interrupt task until all interrupts have been reenabled.

deferred printing: A method of printing whereby some printer drivers record each page of a document's printed image in a structure similar to a QuickDraw picture, which the driver writes to a spool file. An application must use the PrPicFile procedure to send the spool file to the printer. Deferred printing is also known as spool printing

See also: draft-quality printing

deferred task: An interrupt task whose execution has been postponed until interrupts have been reenabled.

Deferred Task Manager: The part of the Mac OS that allows you to defer the execution of lengthy interrupt tasks until interrupts have been reenabled.

deferred task queue: An operating-system queue that contains deferred task records.

deferred task record: A record that contains information about a deferred task. Defined by the DeferredTask data type.

deferred translation: The process of saving a file in native format and waiting to provide translation until the user closes the file.

definition function: A function that defines the appearance and behavior of some user interface element (for example, a control, list, or window)

See also: stub definition function

definition resource: A resource that contains a definition function

See also: stub definition resource

definition stub library: The import library used by the linker to resolve imports in the application (or other fragment) being linked. The definition stub library defines the external programming interface and data format of the library. Also called link-time library

See also: implementation library, stub library

definition version: The version of an import library used by the linker to resolve imports in the application (or other fragment) being linked. The definition version defines the external programming interface and data format of the library

See also: implementation version

delimiter

See: command delimiter

delimiter information record: A structure that defines the characters used to indicate the beginning and end of a command embedded in text. Defined by the DelimiterInfo data type.

delivery indication: Information within a report that indicates the successful delivery of a specific message to a specific recipient.

denormalized number: A nonzero binary floating-point number whose significand has an implicit leading bit of 0 and whose exponent is the minimum exponent for the number's data format. Also called denorm

See also: normalized number

deny modes: A set of file permissions that specify what abilities should be denied to users attempting to open a file fork already opened by another user

See also: access modes

depth: A number indicating the position in front to back order at which a picture item is drawn. The greater a shape's depth, the more other shapes are drawn on top of the shape.

dereference: To refer to a block by its master pointer instead of its handle.

derived font: A font whose characteristics are partially determined by modifying an intrinsic font. A derived font might be one whose characters are scaled from an intrinsic font to achieve a desired size or are slanted to achieve an italic style.

derived media handler component: A component that allows the Movie Toolbox to access the data in a media. Derived media handler components isolate the Movie Toolbox from the details of how or where a particular media is stored. This not only frees the Movie Toolbox from reading and writing media data, but also makes QuickTime extensible to new data formats and storage devices. These components are referred to as derived components because they rely on the services of a common base media handler component, which is supplied by Apple

See also: base media handler component

DES

See: Data Encryption Standard (DES)

descent line: An imaginary horizontal line that coincides with the bottoms of character descenders (such as the tail on a lowercase p) extending farthest below the baseline

See also: ascent line

descriptor list: A descriptor record of data type AEDescList whose data handle refers to a list of descriptor records.

descriptor record: A data structure of type AEDesc that consists of a handle to data and a descriptor type that identifies the type of the data referred to by the handle. Descriptor records are the fundamental data structures from which Apple events are constructed.

descriptor type: An identifier for the type of data referred to by the handle in a descriptor record.

desktop: The onscreen background upon which all applications display their user interface. The desktop is composed of the objects in the startup volume's desktop folder plus the icons of all other mounted volumes.

desktop database: A Finder-maintained database of icons, file types, applications, version data, and comments for all volumes over 2 MB

See also: Desktop file

Desktop file: A resource file in which the Finder stores icons, file types, applications, version data, and comments for all volumes less than 2 MB

See also: desktop database

Desktop Folder: A directory, located at the root level of each volume, used by the Finder for storing information about the icons that appear on the desktop area of the screen. The Desktop Folder is invisible to the user. What the user sees onscreen is the union of the contents of Desktop Folders for all mounted volumes.

Desktop Manager: A collection of routines that manages the desktop database.

desktop printer: A printer accessible through an icon on the user's desktop. The user prints to a desktop printer by dragging the icon of a document to the printer icon.

desk accessory: A 'mini-application' that is available from the Apple menu regardless of which application you're using"for example, the Calculator, Note Pad, Alarm Clock, Puzzle, Scrapbook, Key Caps, and Chooser.

despool: To open a print file and send its data to a device for printing

See also: spool

despooling: In QuickDraw GX printing, the process during the imaging phase of printing during which each previously spooled page is read from the spool file

See also: imaging phase

destination color: The preexisting color of the destination onto which a shape or pixel is to be drawn

See also: result color, source color

destination color limits: In a transfer mode, limits on the permissible values for destination color to use in transfer-mode calculations

See also: result color limits, source color limits

destination profile: The profile that describes the characteristics of the output device for which the image is destined. The profile is used to color match the image to the device's gamut.

destination rectangle: In TextEdit, the rectangle defining the area in which the text is drawn. Text drawn in the destination rectangle is made visible to the application user in the view rectangle.

destination service access point (DSAP): An 802.2 packet header field that is used to differentiate between different protocols using the 802.2 interface in a single node. One service access point, $AA, is reserved for use by protocols that are not standard IEEE protocols.

DES encryption: A form of secret-key encryption used by the Digital Signature Manager solely for keeping users' private keys secure

See also: secret-key cryptography

detached controller: A movie controller component that is separate from its associated movie.

developer: An individual or organization that creates software or hardware products for commercial, in-house, or personal use.

device: A physical part of a Macintosh computer, or a piece of external equipment, that can exchange information with applications or with the Mac OS. Input devices transfer information into a Macintosh computer, while output devices receive information from a Macintosh computer. An I/O device can transfer information in either direction.

device communications phase: In QuickDraw GX printing, the phase when the data that represents the rendered form of each page is sent to the output device. A printing extension or printer driver can only communicate with the printing device during this phase of printing.

device control entry (DCE): A Device Manager data structure containing information about a device driver.

device coordinates: Paired values that specify a size or location in device space.

device driver: A program that controls devices.

device handler: A low-level routine that communicates with a particular ADB device.

device list: A linked list containing the GDevice records for a user's computer system. The global variable DeviceList holds a handle to the first record in the list.

Device Manager: The part of the Mac OS that controls the exchange of information between applications and device drivers.

device matrix: A 5 by 4 matrix, part of the transfer mode structure, that allows you to manipulate the components of the destination color.

device package: A type of code resource that responds to Chooser messages. The device package is responsible for communicating the user's choices to a device driver.

device profile: A structure that provides a means of defining the color characteristics of a given device in a particular state

See also: profile, abstract profile, color space profile, named color space profile

device space: The coordinate system that defines the position and scale (pixel size) of a specific view device

See also: geometry space, global space, local space

device-independent color spaces

See: CIE-based color spaces

device-linked profile: A profile that combines multiple profiles, such as various device profiles associated with the creation and editing of an image.

de facto C++ standard: The current C++ language definition described in the working paper American National Standard for Information Systems"Programming Language"C++, ANSI X3J16.

diacritic

See: diacritical mark

diacritical mark: A sign that modifies the implicit sound or value of the character with which it is associated. For example, in the Roman system, the acute accent (\xC7) is a diacritical mark.

dial: A control, similar to a scroll bar, that graphically represents the ranges of values that a user can set or that simply displays the value, magnitude, or position of something, typically in some pseudo-analog form.

dialect: A version of a scripting language that resembles a specific human language or programming language; for example, the AppleScript scripting language provides dialects that resemble English, Japanese, and other languages

See also: AppleScript scripting language

dialog box: A window that an application displays on the screen to solicit information from the user

See also: modal dialog box, modeless dialog box, movable modal dialog box

dialog color table resource: A resource (of type 'dctb') that lets an application display a dialog box using colors other than the system's default window colors.

dialog hook function: An application-defined function that handles item selections in a dialog box displayed by the Standard File Package.

dialog item list

See: item list

Dialog Manager: The part of the Mac OS that manages the creation, display, and behavior of dialog boxes and alert boxes

See also: alert box, dialog box

dialog record: A data structure of type DialogRecord that the Dialog Manager uses to create dialog boxes and alerts.

dialog resource: A resource (of type 'DLOG') that specifies the window type, display rectangle, and item list for a dialog box.

dialog-item component: The portion of an 'hdlg' resource in which you specify the help messages for a particular item in a dialog or alert box.

dictionary: (1) A collection of records used by input methods and other software modules that let the user enter, format, and process text

See also: main dictionary, user dictionary, pronunciation dictionary

dictionary entry: An item associated with a dictionary key. Each entry consists of raw data plus optional data attributes.

dictionary key: A Pascal search string that may have a maximum length of 129 bytes. Data associated with the key may consist of one or more dictionary entries.

Dictionary Manager: The part of Macintosh system software that makes dictionaries available to input methods.

dictionary record: In a dictionary, a key and one or more entries (data associated with the key).

digest: A number, 16 bytes long, that is calculated from the contents of a given set of data. A digest is like a sophisticated checksum; it is almost impossible for two data sets of any size with any difference to yield the same digest value.

digital signal processor (DSP): A processor that manipulates digital data.

digital signature: A data structure associated with a document or other set of data that uniquely identifies the person or organization that is signing, or authorizing the contents of, the data and ensures the integrity of the signed data. It is a digest of the data to which the signature applies, encrypted with the private key of the signer. A digital signature can be verified by decrypting with the signer's public key. Same as encrypted digest

See also: full signature

Digital Signature Manager: The part of the Mac OS that manages digital signatures and certificates.

digital-to-analog convertor (DAC): A device that converts data from digital to analog form.

digitizer rectangle: The portion of the active source rectangle that you want to capture and convert with a video digitizer component.

direction

See: dominant direction, glyph direction, line direction, text direction

direction boundary: A point between offsets in memory or glyphs on a display, at which the direction of the stored or displayed text changes.

direction level: A hierarchical ranking of dominant direction in a line. Direction levels can be nested so that complex mixed-direction formatting is preserved.

direction override: A means of overriding the directional behavior of glyphs, on a style-run basis, for special effects.

direction run: A contiguous (in memory) sequence of characters having the same right-to-left or left-to-right line direction.

direction-level run: A sequence of contiguous glyphs that share the same text direction.

directory: A subdivision of a volume, available in the hierarchical file system. A directory can contain files and other directories (known as subdirectories).

directory access privileges: A set of conventions for controlling access to a directory.

directory ID: A unique number assigned to a directory. The File Manager uses this number to distinguish a directory from others on the same volume

See also: catalog node ID

direct colors: Up to 16 million colors that have a direct correlation between a value placed in a graphics device and the color displayed onscreen.

direct data area: The area of memory that can be accessed directly through the base register. The direct data area can hold data items or pointers to data items.

direct device: A plug-in video card, a video interface built into a Macintosh computer, or an offscreen graphics world that supports up to 16 million colors having a direct correlation between a value placed in the device and the color displayed onscreen

See also: indexed device

direct memory: Memory directly addressable by an application or by QuickDraw GX

See also: remote memory

direct memory access (DMA): A technique for transferring data in or out of memory without using the CPU.

direct mode: A fast printing mode that uses information built into the printer.

direct mode

See: job format mode

direct parameter: The parameter in an Apple event that contains the data or object specifier record to be used by the server application. For example, a list of documents to be opened is specified in the direct parameter of the Open Documents event

See also: Apple event parameter

direct pixel: A pixel displayed on a direct device. Direct pixels can have pixel values of 16 or 32 bits.

disabled: Describes a menu item or control that cannot be chosen; the item may appear dimmed.

disabled interrupt: An interrupt whose priority level is lower than or the same as that of an interrupt that is currently being serviced.

disabled item: In an alert box or a dialog box, an item for which the Dialog Manager does not report user events. An example of a disabled item is static text, which typically does not respond to clicks.

disclosure triangle: A control that expands a view to disclose additional information about the currently selected item.

discontiguous highlighting: Highlighting that exactly matches the selection range it corresponds to. It may consist of discontiguous areas when the selection range crosses direction boundaries

See also: contiguous highlighting

discontiguous memory: One or more non-continuous blocks of memory. For example, a graphics client heaps might be discontiguous.

discontinuous selection: A type of selection range in which the selected characters themselves are not contiguous in memory. Not to be confused with discontinuous highlighting.

discrete resolution: A printing resolution that has been predefined by a printer driver. A printer supporting discrete resolution prints only a limited number of such resolutions

See also: variable resolution

disk: A physical medium capable of storing information.

disk cache: A part of RAM that acts as an intermediate buffer when data is read from and written to file systems on secondary storage devices.

disk formatting: The process of writing special information onto a disk so that the disk driver can read from and write to the disk.

disk initialization: The process of making a disk usable by the Mac OS.

disk initialization dialog box: A dialog box asking the user whether a disk should be ejected or initialized.

Disk Initialization Manager: The part of the Mac OS that manages the process of initializing disks.

disk location record: A data structure that provides information about the location of a fragment in the data fork of a file on disk. Defined by the DiskFragment data type.

disk switch dialog box: A dialog box asking the user to insert a particular disk.

disk verification: The process of reading every bit on the disk to ensure that the disk has been formatted correctly and contains no bad blocks.

disk zeroing: The process of creating on the disk the data structures and files necessary for the disk to be recognized as a hierarchical file system (HFS) volume.

disk-based pixel image: A bitmap pixel image that is stored in a file (rather than in memory) even when the bitmap shape is memory.

disk-inserted event: An event generated when the user inserts a disk in a disk drive or takes any other action that requires a volume to be mounted.

dispatch routine: A routine in a script system that dispatches script utility calls. WorldScript I and WorldScript II each contain a single dispatch routine that works for all compatible 1-byte and 2-byte scripts, respectively.

dispatch table: A table that is part of a script system's script record; it contains the addresses of the script utilities for that script system.

display coordinate system: The QuickDraw graphics world, which can be used to display QuickTime movies, as opposed to the movie's time coordinate system, which defines the basic time unit for each of the movie's tracks.

display line: The horizontal extent of an area for drawing text on a display device. The left and right ends of the display line are the text area's left and right margins.

display list: In a standard file dialog box, the list of files, folders, and volumes at one level of the display hierarchy, from which the user can select items.

display order: (1) The left-to-right order in which glyphs are drawn on a screen by QuickDraw. Because not all text is read left-to-right, the display order of glyphs may be different from the storage order of their corresponding character codes in memory. (2) The left-to-right order in which QuickDraw GX displays glyphs. Display order determines the glyph index of each glyph in a line and may differ from the input order of the text

See also: glyph index, input order, source text

display rectangle: A rectangle that defines the size and location of an item in an alert box or a dialog box. The display rectangle is specified in an item list and uses coordinates local to the alert box or a dialog box.

display text: The visual representation of the text of a typographic shape. Display text consists of a sequence of glyphs, arranged in display order

See also: source text

dispose: To delete a reference to an object. When an application no longer needs an object, it disposes of the object. That action deletes the object from memory if there are no other current references to the object; otherwise, disposing of an object merely decreases its owner count by 1.

disposed handle: A handle whose associated relocatable block has been disposed of.

distinguished name: The complete identifier of the owner or issuer of a certificate. A distinguished name includes elements such as common name, organization, street address, and country.

dither: To approximate colors that a display device cannot draw with patterns of similar colors that the display device can draw.

dithering: A technique used to improve picture quality when you are attempting to display an image that exists at a higher bit-depth representation on a lower bit-depth device. For example, you might want to dither a 24 bits per pixel image for display on an 8-bit screen.

dither level: A property of a view port object. It specifies the number of colors that can be dithered together when drawing a shape to that view port. Also called dither.

divider: A gray line used in menus to separate groups of menu items.

divide-by-zero exception: A floating-point exception that occurs when a finite, nonzero number is divided by zero or some other improper operation on zero has occurred.

DMA

See: direct memory access (DMA)

dNode: A container within an AOCE catalog that contains records, other dNodes, or both.

dNode number: A number assigned by a catalog that uniquely identifies a catalog node within that catalog. Not all catalogs support dNode numbers

See also: pathname

dNode window: A Finder window that displays the dNodes and records contained in a dNode.

document: (1) A file that a user can create and edit. A document is usually associated with a single application, which the user expects to be able to open by double-clicking the document's icon in the Finder. (2) Any collection of information that is displayed in a document window.

document record: An application-defined data structure that contains information about the window, any controls in the window (such as scroll bars), and the file (if any) whose contents are displayed in the window.

document window: A window in which the user enters text, draws graphics, or otherwise enters or manipulates data.

domain name: A name (such as apple.com) that uniquely identifies a computer on the Internet within its domain (for example, '.com' specifies the commercial name domain).

domain name resolution (DNR): The process of translating between an Internet host's domain name and its IP address (and vice versa).

Domain Name System (DNS): An Internet naming service used to convert between domain names (such as Apple.com) and IP addresses (such as 128.12.27.01), and vice versa. The DNS ensures that a computer connected to the Internet can be uniquely identified by either its domain name or IP address.

dominant direction: The direction in which successive groups of glyphs are read. Dominant direction is independent of glyph direction

See also: glyph direction, line direction

dot color: The color of the dots of a halftone.

dot type: The shape of dot employed in a halftone pattern, such as round, line, or triangle.

double buffering: A technique used by the Sound Manager to manage a play from disk. When using this technique, the Sound Manager plays one buffer of sampled-sound data while filling a second with more data. When the first buffer of sound finishes playing, the Sound Manager plays the data in the second buffer while filling the first with more data

See also: play from disk, sampled-sound data

double format: A 64-bit application data format for storing floating-point values of up to 15- or 16-decimal digit precision.

double indirection: The means by which the Memory Manager or an application accesses the data associated with a handle variable.

double page fault: A page fault that occurs while the Virtual Memory Manager is handling another page fault

See also: page fault

double-click time: The greatest interval between a mouse-up and mouse-down event that would qualify two mouse clicks as a double-click.

double-double format: A 128-bit application data format made up of two double-format numbers. It has the same range as the double format but much greater precision.

dpi: Dots per inch in the x and y directions; used to measure the resolution of a screen or printer. The higher the value, the finer the detail of the image

See also: resolution

draft-quality printing: The method by which printer drivers convert into drawing operations calls only to QuickDraw's text-drawing routines. The printer driver sends these routines directly to the printer instead of using deferred printing to capture the entire image for a page in a spool file. Draft-quality printing, which is supported on the ImageWriter printer driver, produces quick, low-quality drafts of text documents that are printed straight down the page, from top to bottom and left to right

See also: enhanced draft-quality printing

drag: A user action that moves an item from one location to another. The user begins the drag by selecting an item. Then the user may drag the item around the desktop, through application windows, searching for a place to drop the selection. The user ends the drag by dropping the item at the chosen destination.

Drag Manager: The part of the Mac OS that manages the dragging of objects from, within, or to one of your application's windows

See also: drag

drag receiver: The destination for an item being dragged.

drag region: The window frame, including the title bar and window outline, but excluding the close box, zoom box, and collapse box. The user can move a window on the desktop by dragging the drag region

See also: frame

drawing error: A QuickDraw GX error indicating why your shape did not draw successfully. The GXGetShapeDrawError function posts such a single error.

drawing process sequence: The sequence in which QuickDraw processes objects: shape, style, ink, transform, view port, and view device.

drift: To deviate or vary from scheduled execution.

drift-free: Executed precisely as scheduled, without drifting.

driver

See: device driver

driver reference number: A number that identifies each installed device driver. It is the one's complement of the driver's unit number.

drive queue: A list of all volumes connected to the computer.

drop capital: A large uppercase letter that drops below the main line of text for aesthetic reasons.

drop-in

See: application extension

drop-in addition

See: plug-in

drop-launch: To drag a document's icon onto an application's icon, thereby opening the document.

drop-sample conversion: A form of sample rate conversion that uses an existing sample as an interpolated sample point

See also: linear interpolation

DSAP

See: destination service access point (DSAP)

DSP

See: digital signal processor (DSP)

DTE

See: data terminal equipment (DTE)

dual caret: A high caret and a low caret, each measuring half the line's height. The dual caret appears only when the text insertion point is at the boundary between two direction runs in a line of text. The high (primary) caret is displayed at the primary caret position, corresponding to the character offset in the direction run that corresponds to the system direction. The low (secondary) caret is displayed at the secondary caret position, corresponding to the character offset in the direction run that is counter to the system direction. When the caret position is unambiguous (not on a direction boundary), the primary and secondary carets are at the same position, so the user sees one caret. Also called split caret

See also: left-to-right caret, right-to-left caret, single caret

duplicating: As used by AOCE utility routines: the process of copying the pointers to data structures and not the actual data structures themselves

See also: copying

duration: A time interval. Durations are time values that are interpreted as spans of time, rather than as points in time.

dynamically assigned socket: One of two classes of sockets that DDP maintains. When an application opens a socket without specifying a number within the range of statically assigned sockets, DDP dynamically assigns the application a socket from a pool of available sockets

See also: statically assigned socket

dynamically linked library

See: import library

dynamic bus sizing: The ability of certain members of the 680x0 family of microprocessors to allow I/O devices with 8-bit and 16-bit data paths to work with the processor's 32-bit data bus.

dynamic highlighting: The process of continually drawing and redrawing the highlighted area as the user moves the cursor through the text while holding down the mouse button.

dynamic window: A window that can change its title or reposition any of the objects within its content area.