V
- validation
- A set of debugging functions that cause one or more actions to occur whenever a QuickDraw GX function is called or whenever the internal memory manager is called
See also: public validation, internal validation
- validation error
- A QuickDraw GX error detected and posted by the debugging version with validation error checking turned on. The parameters of objects are checked to ensure that the object is valid
See also: validation
- variable
- A named storage location for a modifiable value.
- variable resolution
- Any printing resolution within a range bounded by maximum and minimum values
See also: discrete resolution
- variation axis
- A range included in a font by the font designer that allows a font to produce different typestyles.
- variation code
- (1) A number that selects among variations supported by a single window definition function or control definition function. The variation code is stored in the low-order 4 bits of the window definition ID or control definition ID
See also: control definition function, control definition ID, window definition function
- VBL
See: vertical retrace interrupt
- VBL task
- A task executed during a vertical retrace interrupt
See also: slot-based VBL task, system-based VBL task
- VBL task record
- A data structure that contains information about a VBL task. Defined by the VBLTask data type.
- VCB
See: volume control block (VCB)
- VCB queue
See: volume control block queue
- vector
See: transition vector
- vector imaging system
- The imaging system provided by QuickDraw GX that converts QuickDraw GX shapes into data and control sequences for vector output devices such as graphic plotters.
- verb
See: selector
- verification
See: disk verification
- verify
- To establish the authenticity of a digital signature. Verification consists of determining that the signed document has not changed since it was signed and affirming that the public key used to decrypt the signature is valid.
- version record
- A structure that contains version information. Defined by the NumVersion data type.
- vertical blanking interrupt (VBL)
See: vertical retrace interrupt
- vertical blanking rectangle
- A rectangle that defines a portion of the input video signal that is devoted to vertical blanking. This rectangle occupies lines 10 through 19 of the input signal. Broadcast video sources may use this portion of the input signal for closed captioning, teletext, and other nonvideo information. Note that the blanking rectangle cannot be contained in the maximum source rectangle.
- vertical retrace interrupt
- An interrupt generated by the video circuitry each time the electron beam of a monitor's display tube returns from the lower-right corner of the screen to the upper-left corner. Also known as vertical blanking interrupt.
- Vertical Retrace Manager
- The part of the Operating System that schedules and executes tasks during a vertical retrace interrupt.
- vertical retrace queue
- A list of the tasks to be executed during a vertical retrace interrupt.
- VIB
See: volume information block (VIB)
- video device
- A piece of hardware, such as a plug-in video card or a built-in video interface, that controls a screen.
- video digitizer component
- A component that provides an interface for obtaining digitized video from an analog video source. The typical client of a video digitizer component is a sequence grabber component, which uses the services of video digitizer components to create a very simple interface for making and previewing movies. Video digitizer components can also operate independently, placing live video into a window.
- view
- An item or field in an information page displaying one or more property values.
- view device
- A QuickDraw GX object associated with a view port object. It describes the characteristics of a given physical display device such as a monitor or a printer.
- view group
- A QuickDraw GX object that consists of a grouping of view ports and view devices.
- view list
- A data structure that specifies individual views o
n an information page. Each item in the list includes the graphic rectangle containing the view, the number of the property that provides the information to be displayed, the type of view, and information specific to that view type.
- view port
- A QuickDraw GX object associated with a transform object. A view port describes the characteristics of the drawing environment for individual QuickDraw GX shapes.
- view port hierarchy
- An ordered arrangement of view ports that allows for such features as windows within windows, including multiple windows within a single window.
- view port list
- A property of a transform object. This list is an array of references to the view ports that the shapes associated with that transform can be drawn to.
- view rectangle
- In TextEdit, the rectangle defining the portion of the window within which text is actually displayed. Text drawn in the destination rectangle is made visible to the application user in the view rectangle.
- virtual bus
- The grouping of SCSI devices on different buses into a single logical bus for compatibility with software that cannot address multiple buses.
- virtual ID
- The SCSI ID of a device on the virtual bus.
- virtual key code
- The key code that an application receives in keyboard events. It is the value produced after a raw key code has been mapped through the key-map ('KMAP') and key-remap ('itlk') resources
See also: character code
- virtual machine (VM)
- A software package that simulates the actions of a microprocessor. A virtual machine can mimic an existing processor (such as the 68K emulator on PowerPC-based, Mac OS_compatible computers) or parse special VM-specific code. Java code requires a virtual machine environment to execute
See also: Java runtime environment, Java runtime session
- virtual memory
- Addressable memory beyond the limits of available physical memory. An operating system extends physical memory by storing on a secondary storage device, such as a hard disk, code and data not immediately required by the CPU.
- Virtual Memory Manager
- The part of the Operating System that provides virtual memory.
- virtual queue
- A view of a physical message queue through which an application can open, close, and list messages. More than one virtual queue can be associated with a single physical queue
See also: physical queue
- visible region
- The part of a window's graphics port that is actually visible on the screen"that is, the part that is not covered by other windows.
- voice
- (1) The set of parameters that specify a particular quality of synthesized speech. A voice is designed to work with a particular speech synthesizer. (2) A sampled sound played at varying rates to produce a number of different pitches or notes
See also: instrument
- voice description record
- A structure that contains information about a voice. Defined by the VoiceDescription data type.
- voice file information record
- A structure that contains information about the file in which a voice is stored and the resource ID of the voice within that file. Defined by the VoiceFileInfo data type.
- voice specification record
- A structure that provides a unique specification that you must use to obtain information about a voice. Defined by the VoiceSpec data type.
- volatile register
- A register whose contents need not be preserved across subroutine calls
See also: nonvolatile register
- volume
- (1) A portion of a storage device that is formatted to contain files. (2) See amplitude, speech volume.
- Volumes control panel
- A subpanel of the Sound control panel that allows the user to select volumes
See also: Alert Sounds control panel, Sound In control panel, Sound Out control panel
- volume bitmap
- A data structure that contains a series of bits indicating which blocks on the volume are allocated. Volume bitmaps exist both on HFS volumes and in memory.
- volume catalog
See: catalog file
- volume control block queue
- A list of the volume control blocks for all mounted volumes.
- volume control block (VCB)
- A nonrelocatable block of memory in the system heap that contains information about a specific mounted volume, including the information from the volume's master directory block.
- volume format
- The structure of file and folder information on a disk. The hierarchical file system (HFS) and HFS+ are examples of volume formats.
- volume index
- A number identifying the position of a mounted volume listed in the volume control block queue.
- volume information block (VIB)
- volume name
- A sequence of up to 27 characters, excluding colons (:), that identifies a volume.
- volume reference number
- A unique number assigned to a volume when it's mounted; used to refer to the volume.
- VOX recording
- A feature that allows sound recording only when the sound to be recorded exceeds a certain amplitude.
- VOX stopping
- A feature that stops sound recording when the sound falls below a certain amplitude.