e

E

EASC

See: Enhanced Apple Sound Chip (EASC)

echoer socket: On every node, the statically assigned DDP socket, socket number 4, that AEP uses to receive packets sent from other nodes over DDP and echo those packets back to the sending node

See also: AEP Echoer

Echo Reply packet: A packet sent from the AEP Echoer to the originator of the Echo Request packet. Whenever the AEP Echoer receives an Echo Request packet, it modifies the function field, which is the first byte in the packet's data portion, setting it to a value of 2 to indicate that the packet is now a reply packet, then it calls DDP to send a copy of the packet back to the socket from which it originated

Echo Request packet: A packet send to the AEP Echoer from a DDP client. The first byte of the data portion of the packet serves as a function field. When this byte is set to 1, the packet is an Echo Request packet. When the AEP Echoer receives an Echo Request packet, it modifies the function field to now identify the packet as an Echo Reply packet. Then the AEP Echoer calls DDP to send a copy of the packet back to the socket from which it originated

See also: Echo Reply packet

edge: A line or curve that makes up part of a shape contour.

edge offset: A byte offset into the source text of a layout shape that specifies a position between byte values. Edge offsets in source text are related to caret positions in display text

See also: byte offset, caret position

editable text field: A control that appears as a rectangular box inside a dialog box. The user enters text in the edit text field to provide information to an application

See also: static text field

editable text frame: A control that provides a means for non-standard edit text fields to provide Appearance-based features, such as focus rings

edition: The data written to an edition container by a publisher. A publisher writes data to an edition whenever a user saves a document that contains a publisher, and subscribers in other documents may read the data from the edition whenever it is updated

See also: publisher, subscriber

edition container: A file that holds edition data, represented on the desktop by an edition icon. An edition container obtains its data from a publisher within a document

See also: edition, publisher

Edition Manager: The collection of routines that allows applications to automate copy and paste operations between applications, so that data can be shared dynamically.

edit state: Information defining the current state of a movie or track with respect to an edit session. The Movie Toolbox uses edit states to support its undo facilities.

eight-color system: The eight predefined colors provided by basic QuickDraw for display on color screens and color printers.

ELAP

See: EtherTalk Link-Access Protocol (ELAP)

element: An Apple event object contained by another Apple event object specified as the element's container. An Apple event object can contain many elements of the same element class, whereas an Apple event object can have only one of each of its properties

See also: Apple event object, container, element classes, property

element classes: In the Apple Event Registry: Standard Suites, a list of the object classes for the elements that an Apple event object of a given object class can contain

See also: Apple event object, object class

embedded speech command: In a buffer of input text, a sequence of characters enclosed by command delimiters that provides instructions to a speech synthesizer.

embedding alignment: The alignment of a data item within a composite data item (such as a data structure)

See also: natural alignment

embedding application: The application on a host platform (for example, a Web browser) that instantiates a Java session and executes Java applets or applications.

embedding hierarchy: A mechanism used by the Dialog Manager to establish control drawing order, hit-testing, and keyboard focus. The Dialog Manager positions dialog items in an embedding hierarchy based on both visual containment and the order in which items are added to a dialog box during creation. Controls that already exist in the window will be containers for new controls if they both visually contain the control and support embedding. For example, a tab control may have a radio button embedded within it

See also: control, dialog box, keyboard focus, root control

empty handle: A handle whose master pointer has the value NIL (possibly indicating that the underlying relocatable block has been purged).

empty shape: A type of QuickDraw GX shape. Empty shapes have no geometry, are contained by every other shape, and do not appear when drawn.

emulated application: An application whose executable code is not in the instruction set architecture of the CPU. An emulated application relies on an emulator to translate its code into that instructi on set

See also: 680x0 application

emulation: The process by which a microprocessor is able to execute code in an instruction set different from its native instruction set

See also: 68LC040 Emulator

emulation environment: The 680x0-compatible environment on PowerPC processor-based Macintosh computers provided by the 68LC040 Emulator and the Mixed Mode Manager.

emulator

See: 68LC040 Emulator

enable: To make a script system available. The Script Manager and the script extensions enable only those script systems that have a required set of resources and fonts

See also: install, initialize

enabled item: In an alert box or a dialog box, an item for which the Dialog Manager reports user events. For example, the Dialog Manager reports clicks in an enabled OK button.

enclosure: A file or folder sent along with a letter, like an attachment to a conventional hard-copy letter

See also: content enclosure, regular enclosure

encoding: A style object property. It is the type of character encoding used to represent the text of a shape, as well as its script and language.

encoding/rendering resource: An international resource of type 'itl5'. The encoding/rendering resource specifies character encoding or rendering information for a particular script system. The encoding/rendering resource is optional and has different formats in 1-byte and 2-byte script systems.

encrypt: To hide data by putting it into a scrambled (illegible) state, in such a way that its original state can be restored later. In most cryptographic systems, encryption is performed by mathematically manipulating the data with a large number called a key.

encrypted digest

See: digital signature

encryption: The process of encoding data based on an algorithm that makes the data unreadable by anyone other than the intended recipient.

encryption key

See: key

ending prosody: The rhythm, modulation, and stress patterns associated with the end of a sentence of speech.

end-of-file (EOF)

See: logical end-of-file, physical end-of-file

Enhanced Apple Sound Chip (EASC): A modified Apple Sound Chip that generates stereo sound using pulse-code modulation

enhanced draft-quality printing: The method by which some printer drivers print bitmaps, pixel maps, and text without writing to or reading from a spool file. The ImageWriter printer driver, for example, supports enhanced draft-quality printing

See also: deferred printing, draft-quality printing

enhanced Sound Manager: Any version of the Sound Manager greater than 2.0.

entity name: A name that is associated with a network entity to register that entity with NBP. An entity name consists of three fields: object, type, and zone.

entry

See: dictionary entry

entry point: A location (offset) within a module.

environmental access switch: A switch, recommended in the FPCE technical report, that specifies whether a program accesses the rounding direction modes and exception flags.

environmental controls: The rounding direction modes and the exception flags.

environmental selector: A Gestalt selector code, used with the Gestalt function, that returns information about the operating environment that can be used by an application to guide its actions

See also: informational selector

EOF

See: logical end-of-file, physical end-of-file

epilog: A standard piece of code at the end of a routine that restores any nonvolatile registers saved by the routine's prolog, tears down the routine's stack frame, and returns to the caller

See also: prolog

erase: To draw both the outline of a shape and its interior with the background pattern for the current graphics port. The background pattern is typically solid white on a black-and-white screen or a solid background color on a color screen. Making the shape blend into the background pattern of the graphics port effectively erases the shape.

error: A single descriptive phrase that is posted by QuickDraw GX whenever an application is unable to execute. Execution is terminated at the nonexecutable function. Each error message is assigned a unique number in the range _27999 through _27000. Errors are posted in both the debugging and non-debugging versions of QuickDraw GX.

error callback function: An object callback function that gives the Apple Event Manager an address. The Apple Event Manager writes to this address the descriptor record it is currently working with if an error occurs during the resolution of an object specifier record

See also: object callback function

error callback procedure: An application-defined procedure that is executed whenever the Speech Manager encounters an error in an embedded speech command in a buffer of input text.

error diffusion: A process of dithering for bitmaps in which the error (the difference between the computed color of a given pixel and the nearest color available on the view device) is passed to adjacent pixels.

Ethernet Phase 1 packets: The original style of Ethernet packet as defined by the IEEE 802.3 protocol. If the value of the last 2 bytes in the packet header is greater than 1500, the packet is an Ethernet Phase 1 packet.

Ethernet Phase 2 packets: The style of Ethernet packet defined by the IEEE 802.2 protocol. If the value of the last 2 bytes in the header is less than or equal to 1500, the packet is an Ethernet Phase 2 packet.

EtherTalk: The data link that allows an AppleTalk network to be connected by Ethernet cables.

EtherTalk Link-Access Protocol (ELAP): The AppleTalk link-access protocol used in an EtherTalk network. ELAP is built on top of the standard Ethernet data-link layer.

evaluation format: The data format used to evaluate the result of an expression. The evaluation format must be at least as wide as the expression's semantic type. (It may be the same as the semantic type.)

event: The means by which the Event Manager communicates information about user actions, changes in the processing status of the application, and other occurrences that require a response from the application.

event class: An attribute that identifies a group of related Apple events. The event class appears in the message field of the Apple event's event structure. The event class and the event ID identify the action an Apple event performs

See also: Apple event attribute, event ID

event filter function: An application-defined routine that supplements the Dialog Manager's ability to handle events"for example, an event filter function can test for disk-inserted events and can allow background applications to receive update events.

event ID: An attribute that identifies a particular Apple event within a group of related Apple events. The event ID appears in the where field of the Apple event's event structure. The event ID and the event class identify the action an Apple event performs

See also: Apple event attribute, event class

event loop: A section of code that repetitively retrieves events from the Event Manager and dispatches to the appropriate event-handler.

Event Manager: The part of the Mac OS that manages the communication of information among your application, other applications, and the system

See also: event

event mask: An integer with one bit position for each event type. You specify an event mask as a parameter to Event Manager routines to specify the event types you want your application to receive, thereby disabling (or 'masking out') the events you are not interested in receiving.

event priority: The order in which an event of a particular type is returned to an application.

event record

See: event structure

event structure: A data structure of type EventRecord that your application uses when retrieving information about an event. The Event Manager returns, in an event structure, information about what type of event occurred (a mouse click or keypress, for example) and additional information associated with the event.

event-driven programming: A way of structuring an application so that it is guided by events reporting a user's actions and other occurrences in the computer.

even-odd fill: A shape fill that follows the even-odd rule. Same as solid fill.

even-odd rule: A rule used when drawing filled shapes to determine which areas are filled. The even-odd rule does not fill areas which lie under overlapping contours

See also: winding-number rule

exactly-once (XO) transaction: A type of ATP transaction that ensures that the responder application receives a specific request only once.

exception: An error or other special condition detected by the microprocessor in the course of program execution. The floating-point exceptions are invalid, underflow, overflow, divide-by-zero, and inexact.

exception code: A constant that indicates which kind of exception has occurred.

exception flag: Each exception has a flag that can be set, cleared, and tested. It is set when its respective exception occurs and stays set until explicitly cleared.

exception handler: Any routine invoked automatically by the processor in any of a variety of exceptional circumstances. For example, the trap dispatcher is an exception handler that is called by the processor, to dispatch unimplemented A-line instructions.

exception information record: A data structure that contains information about an exception, such as the exception kind, the machine state at the time of the exception, and so forth. Defined by the ExceptionInformation data type.

Exception Manager: The part of the Macintosh system software that handles exceptions that occur during the execution of PowerPC applications or other software.

exception stack frame: A block of data placed on the stack automatically by the processor when an exception occurs.

excluded: A permission level prohibiting all read and write access to the area

See also: read-only, read/write

exclude mode: A transfer mode type in which the destination color remains visible only where the source is transparent, and the source color is copied anywhere the destination is transparent.

exclusive access: The file access permissions that deny other users both read and write access to a file.

executable resource: Any resource that contains executable code

See also: accelerated resource, private resource

executable resource: Any resource that contains executable code

See also: accelerated resource

execution time: The general span of time during which programs run on a computer

See also: generation time, launch time

exhaustive search: A search using an algorithm that scans an entire volume to look for possible matches.

expansion

See: audio expansion

expansion card: A removable printed circuit card that plugs into a connector (slot) in the computer's expansion interface. Macintosh computers can use expansion cards designed for the NuBus expansion interface or for the processor-direct slot expansion interface. Also called slot cards or simply cards.

explicit color: A color that specifies an index value in the devices color table rather than an RGB color.

explicit cross-mode call: A call to code that is in a different instruction set architecture from the caller's, caused by the caller explicitly calling the CallUniversalProc function.

explicit scaling: Scaling performed by the Font Manager when an application specifically asks QuickDraw to change text from a particular size or shape to another

See also: implicit scaling

explicit translation: The conversion of a file or scrap requiring direct intervention from an application

See also: implicit translation

exponent: The part of a binary floating-point number that indicates the power to which 2 is raised in determining the value of the number. The wider the exponent field in a numeric data format, the greater range the format will handle.

export: (1) To make a symbol externally visible. Also, a synonym for exported symbol. (2) A data item or executable routine within a fragment that is made available for use by other fragments.

exported symbol: A symbol in a fragment that is visible to some other fragments

See also: import library, imported symbol

expression evaluation method: The method by which an evaluation format is determined for an expression.

extended addressing: A method of addressing that allows an extended network to use a range of network numbers. In principle, extended addressing allows an extended network to have over 16 million (224) nodes. In any specific implementation, the hardware or software might limit the network to fewer nodes.

Extended Common Object File Format (XCOFF): A format of executable file generated by some PowerPC compilers

extended DDP header

See: long DDP header

extended item list: A resource that extends an item list ('DITL') resource by responding automatically to items when they are manipulated by the user.

extended network: An AppleTalk network that allows addressing of more than 254 nodes. An extended network can support multiple zones.

extended parameter RAM: The 236 bytes of parameter RAM that is reserved by the system software.

extended sound header: A sound header that can describe monophonic and stereo sampled-sound data, but not compressed sound data. Defined by the ExtSoundHeader data type

See also: compressed sound header, sampled sound header

extended version 2 picture format: The format for all pictures created with the OpenCPicture function. Available on all Macintosh computers running System 7, this format allows applications to specify resolutions when creating images.

extension: (1) An object class that duplicates all the characteristics of an object class of the same name and adds some of its own. Like a word in a dictionary, a single object class ID can have several related definitions. (2) See application extension, system extension.

Extensions folder: A directory located in the System Folder for storing system extension files such as printer and network drivers and files of types 'INIT', 'scri', and 'appe'.

extension type: A four-character value that identifies a type of messaging system that uses a specific addressing convention; for example, an AppleLink system or an X.400 system.

extent: A contiguous range of allocation blocks that have been allocated to some file.

extents overflow file: A special file containing all extent data records that are not stored elsewhere by the File Manager.

extent data record: A data record that contains three extent descriptors. Extent data records are stored in the leaf nodes of the extents overflow file, in the catalog file, and in the boot blocks.

extent descriptor: A description of an extent, consisting of the number of the first allocation block of the extent followed by the length of the extent. Defined by the ExtDescriptor data type.

external catalog: A catalog or database accessible to AOCE-enabled applications through the Catalog Manager API. For a user to have access to an external catalog, the user's AOCE system must include a CSAM for that catalog service.

external code: Any block of executable code that is not directly contained in an application or other software.

external entry point: In the CFM-68K runtime architecture, the entry point to a routine when called indirectly or from another fragment. Typically this entry point allows inclusion of instructions to set up an A5 world for the called routine before entering the internal entry point

See also: internal entry point

external messaging system: Any non-AOCE messaging system.

external reference: A reference to a routine or variable defined in a separate code segment, compilation unit, or assembly.

external service: A service that is not provided automatically with PowerTalk system software and PowerShare servers.