25. Acronyms and Glossary

The following acronyms are used in this book.

ACM

Association for Computing Machinery

ANSI

American National Standards Institute

API

Application Program Interface

CGI

Computer Graphics Interface

CMU

Carnegie-Mellon University

CWI

Centrum voor Wiskunde en Informatica

FMS

Frame Management System

GINO

Graphical Input/Output (graphics package)

GKS

Graphical Kernel System

GSPC>

Graphic Standards Planning Committee of SIGGRAPH

ICL

International Computers Limited

IPC

Inter Process Communication

ISO

International Organization for Standardization

IT

Information Technology

ITC

Information Technology Centre (Carnegie-Mellon University)

MIT

Massachusetts Institute of Technology

MMI

Man-Machine Interface or Interaction

NDC

Normalized Device Coordinates

NFS

Network File Server

OI

Operator Interface

PARC

Palo Alto Research Centre of Xerox Corporation

PHIGS

Programmer's Hierarchical Interactive Graphics System

PIT

Programmable Input translation

RAL

Rutherford Appleton Laboratory

RPC

Remote Procedure Call

SIGGRAPH

ACM Special Interest Group on Computer Graphics

TIP

Terminal Interface Package

UI

User Interface

VDI

Virtual Device Interface

VGTS

Virtual Graphics Terminal Service

WMS

Window Management System

WYSIWYG

What You See Is What You Get

Accelerator:

an alternative interaction technique (eg for command invocation) which is faster to use, but may be harder to learn or remember; for example, use of a reserved mouse-button instead of selection from a menu. Accelerators are typically provided for frequently used commands.

Accent:

a message-based distributed operating system kernel, originally developed on PERQ workstations by Carnegie-Mellon University's Spice project.

Adobe imaging model:

the imaging model provided with the PostScript language [1] from Adobe Systems, described in [69].

Application Program Interface (API):

the software interface between an application program and the window manager.

Asynchronous:

(of events, notifications etc): occurring at times unpredictable by the recipient. For example, in relation to input, the term is typically used to describe systems in which the window manager notifies an application by a software interrupt that input has been received from the operator.

BitBlt:

bit boundary block transfer; see RasterOp and [49].

Bitmap:

an image composed of an array of pixels, and in a machine-related sense, an area of memory where such an array is stored.

Bravo:

a display-based WYSIWYG document editor developed at Xerox PARC for the Alto workstation.

Canvas:

the abstract object on which an application can draw in the SunDew system.

Caret:

the symbol used to mark the point of insertion in some text editors.

Cedar:

an integrated program development environment developed at Xerox PARC.

Cedar graphics model:

forerunner of the Adobe imaging model[69].

Child window:

a window directly subordinate to another (its parent), in a hierarchical window system.

Click:

the action of pressing and quickly releasing a button within some time interval to cause an input event. For example on a mouse a button click is distinct from dragging or drawing actions while a button is held down.

Client:

an application program which requests services from the window manager.

Cluster:

a group of pads corresponding to a window on the Rainbow terminal.

Computer Graphics Interface (CGI):

a proposed ISO standard defining the functionality required between a graphics system and a device.

CORE:

a graphics system developed by the Graphic Standards Planning Committee of ACM SIGGRAPH [24].

Courteous windows:

windows which save and restore the images of any windows or their parts that they obscure.

Covered window paradigm:

windows may overlap on the display, one window thus (partially) obscuring the contents of another.

Cursor:

a visible representation on a display of the position of a graphical input device, which follows the movement of the device.

Cut and paste:

the ability to select output from an application running in one window and to supply it as input to an application running in another window. In editors, the inter- or intra-document movement of text.

Damage repair:

restoring a window to its current appearance when it becomes (partially or totally) uncovered.

Desktop metaphor:

likening windows to pieces of paper on a desk. A window may be on top of another window just as one piece of paper may be on top of another. Windows can be moved around the screen and shuffled, just as pieces of paper can on a desktop.

Display list, display file:

a set of commands, for example line drawing and character drawing commands, generating a picture. The term is normally associated with vector displays, in which a picture is maintained on a screen by repeated regeneration by a display processor, from a stored display list.

Double click:

two consecutive clicks (q.v.) occurring within a certain time interval. In some systems, single and double clicks have different (possibly related) meanings.

Events:

input data normally generated by input actions, for example depressing a mouse button.

Fixup:

the process of recreating the image of an obscured portion of a window. A common example is scrolling a partially obscured window by moving the image. This could be achieved by moving the unobscured part of the window and fixing up the portion which was previously obscured.

Geometry pipeline:

a sequence of geometric transformations (including clipping) to which coordinate data are subjected.

Gino: GINO-F:

a graphics package developed by the CAD Centre which became a de facto standard in the UK. It encompasses input and 3D graphical output.

GKS:

the Graphical Kernel System. An ISO International Standard (ISO 7942) for computer graphics, providing 2D graphical output and input [28].

GKS-3D:

an extension of GKS to include 3D graphics. This standard is currently under development [29].

Grouping:

a collection of objects which can be manipulated as a single entity.

Guarded button:

a protected button. Before the button can be activated, the guard must be removed by a click. If a second click does not activate the button within some time interval, the button returns to the guarded state. The Cedar system used this concept.

Icon:

a small pictogram capable variously of representing windows, operations, operands, processes or process status.

Imaging model:

a set of graphics primitives, and the protocol for their display.

Input model:

a set of input primitives and modes, and associated protocol.

Inter Process Communication (IPC):

a communications mechanism and protocol between separate processes, b1y on different processors, usually implemented by message-passing.

Lightweight processes:

processes which have only small overheads for context switching; commonly a group of lightweight processes share a single address space.

Listener:

the window which currently receives input.

Mode:

a state of the system, sometimes invisible to the user, and usually lasting for a period of time, which causes input actions to be interpreted in a particular way. Commonly the same input action has different effects in different modes.

Mouse ahead:

generating input from the mouse buttons in advance of the application being ready to process such input.

Name stripe:

see title bar.

Object-oriented language:

a programming language consisting of a collection of objects (containing data) that receive messages identifying functions to be performed and any further operands required. Each object has a set of messages it can understand, called methods. Objects are grouped into classes, which themselves may be a subset of other classes. Smalltalk [21] embodies an object-oriented language.

Operator:

see user.

Operator interface:

the interface between the operator and the window manager.

Overlapping window paradigm:

see covered window paradigm.

Parent window:

that window which is the next level up from a given (child) window, in a hierarchical windowing system.

PHIGS:

Programmer's Hierarchical Interactive Graphics System, a standard under development within ISO [6].

Pointing device:

an input device, such as the mouse. Input from the pointing device IS frequently guided by feedback from the display.

Pop-up menu:

a menu that appears on demand, at or near the current cursor position, and disappears when an item has been selected.

Port:

an inter process communication channel.

PostScript:

a Forth-like page description programming language [1], developed by Adobe Systems Inc., to describe the appearance of text, images and graphics material on a printed page efficiently.

Pull-down menu:

a variant of pop-up menu which appears when a mouse button is pressed over a fixed menu item. The pull-down menu appears to hang downwards, like a roller blind. from the fixed item.

RasterOp:

an operation for merging rectangular source and destination bitmaps. Each pixel in the final destination bitmap is a logical combination (eg and, or) of the corresponding pixels in the source and the initial destination bitmaps. The source and destination bitmaps may overlap.

Retained (cached) windows:

windows whose contents are remembered by the window manager for purposes such as damage repair.

Remote Procedure Call (RPC):

a mechanism enabling a client process to call a procedure in a server process, where client and server are not in the same address space and. indeed. may be located on physically separate systems connected by a network.

Rubber band:

a technique used to give feedback to an operator. A rubber band object is an object whose geometry at any time varies to reflect the state of the input devices controlling it,

Scroll bar:

a region of a window used to control scrolling of the window's contents.

Smalltalk:

an early example of a window-based environment developed at Xerox PARC [21] [27]

Sneak path:

a feedback path which short-circuits the normal user-application-user path. For example, echoing of the currently selected menu item by the window manager would be a sneak path.

SunTools:

a layer in the SunWindows window manager [61].

Synchronous:

(of events. notifications etc): occurring in response to requests from the recipient.

Tiled window paradigm:

individual windows do not overlap on the display.

Title bar:

the area at the top of a window provided by many systems where the system or application can put information that identifies the window.

Trigger:

a physical input device that an operator can use to indicate significant moments in time. Firing a trigger typically generates input events.

TTY emulator:

a software subsystem which emulates a teletype in a window.

Type ahead:

generating input from the keyboard in advance of the application being ready to process such input.

Typescript:

a complete transcript of a TTY session.

User:

user or operator is used to specify the person who uses an already-defined application by sitting at a workstation and interacting with it.

User Interface Management System (UIMS):

a system which allows the user interface to an application to be defined separately from the application itself. Such systems often allow rapid prototyping of user interfaces.

Viewport:

in a conventional graphics system, that area of the display screen onto which output is mapped. In a window management system, a panel or pane of a window into which an application maps output.

Virtual Device Interface (VDI):

now called Computer Graphics Interface (CGI).

Window:

in a conventional graphics system, that portion of the user coordinate space that is mapped onto the viewport. In a window management system, a virtual area associated with an application which is mapped to the display screen under the control of the window manager.

Window descriptor:

information associated with a window giving the window's size and attributes.

Wireframe:

a method of representing objects where only the edges are drawn.