DDK Glossary - M

main window: The window that is positioned relative to the desktop window.

manipulation button: The button on a pointing device a user presses to directly manipulate an object.

map: (1) A set of values having a defined correspondence with the quantities or values of another set. (I) (A); (2) To establish a set of values having a defined correspondence with the quantities or values of another set. (I)

marker box: In computer graphics, the boundary that defines, in world coordinates, the horizontal and vertical space occupied by a single marker from a marker set.

marker symbol: A symbol centered on a point. Graphs and charts can use marker symbols to indicate the plotted points.

marquee box: The rectangle that appears during a selection technique in which a user selects objects by drawing a box around them with a pointing device.

Master Help Index: In the OS/2 operating system, an alphabetic list of help topics related to using the operating system.

maximize: To enlarge a window to its largest possible size.

media window: The part of the physical device (display, printer, or plotter) on which a picture is presented.

memory block: Part memory within a heap.

memory device context: A logical description of a data destination that is a memory bit map. See also device context.

memory management: A feature of the operating system for allocating, sharing, and freeing main storage.

memory object: Logical unit of memory requested by an application, which forms the granular unit of memory manipulation from the application viewpoint.

menu: In SAA Advanced Common User Access architecture, an extension of the menu bar that displays a list of choices available for a selected choice in the menu bar. After a user selects a choice in menu bar, the corresponding menu appears. Additional pop-up windows can appear from menu choices.

menu bar: In SAA Advanced Common User Access architecture, the area near the top of a window, below the title bar and above the rest of the window, that contains choices that provide access to other menus.

menu button: The button on a pointing device that a user presses to view a pop-up menu associated with an object.

message: (1) In the Presentation Manager, a packet of data used for communication between the Presentation Manager interface and Presentation Manager applications. (2) In a user interface, information not requested by users but presented to users by the computer in response to a user action or internal process.

message box: (1) A dialog window predefined by the system and used as a simple interface for applications, without the necessity of creating dialog-template resources or dialog procedures. (2) In SAA Advanced Common User Access architecture, a type of window that shows messages to users. See also dialog box, primary window, secondary window.

message filter: The means of selecting which messages from a specific window will be handled by the application.

message queue: A sequenced collection of messages to be read by the application.

message stream mode: A method of operation in which data is treated as a stream of messages. Contrast with byte stream.

metacharacter: See global file-name character.

metaclass: A class whose instances are all classes. In SOM, any class descended from SOMClass is a metaclass. The methods of a metaclass are sometimes called "class" methods.

metafile: A file containing a series of attributes that set color, shape, and size, usually of a picture or a drawing. Using a program that can interpret these attributes, a user can view the assembled image.

metafile device context: A logical description of a data destination that is a metafile which is used for graphics interchange. See also device context.

metalanguage: A language used to specify another language. For example, data types can be described using a metalanguage so as to make the descriptions independent of any one computer language.

method: One of the units that makes up the behavior of an object. A method is a combination of a function and a name, such that many different functions can have the same name. Which function the name refers to at any point in time depends on the object that is to execute the method and is the subject of method resolution.

method override: The replacement, by a child class, of the implementation of a method inherited from a parent and an ancestor class.

mickey: A unit of measurement for physical mouse motion whose value depends on the mouse device driver that is currently loaded.

micro presentation space: A graphics presentation space in which a restricted set of the GPI function calls is available.

minimize: To remove from the screen all windows associated with an application and replace them with an icon that represents the application.

mix: An attribute that determines how the foreground of a graphic primitive is combined with the existing color of graphics output. Also known as foreground mix. Contrast with background mix.

mixed character string: A string containing a mixture of one-byte and kanji or Hangeul (two-byte) characters.

mnemonic: (1) A method of selecting an item on a pull-down by means of typing the highlighted letter in the menu item. (2) In SAA Advanced Common User Access architecture, usually a single character, within the text of a choice, identified by an underscore beneath the character. If all characters in a choice already serve as mnemonics for other choices, another character, placed in parentheses immediately following the choice, can be used. When a user types the mnemonic for a choice, the choice is either selected or the cursor is moved to that choice.

modal dialog box

In SAA Advanced Common User Access architecture, a type of movable window, fixed in size, that requires a user to enter information before continuing to work in the application window from which it was displayed. Contrast with modeless dialog box. Also known as a serial dialog box. Contrast with parallel dialog box.

Note: In CUA architecture, this is a programmer term. The end user term is pop-up window.

model space: See graphics model space.

modeless dialog box

In SAA Advanced Common User Access architecture, a type of movable window, fixed in size, that allows users to continue their dialog with the application without entering information in the dialog box. Also known as a parallel dialog box. Contrast with modal dialog box.

Note: In CUA architecture, this is a programmer term. The end user term is pop-up window.

module definition file: A file that describes the code segments within a load module. For example, it indicates whether a code segment is loadable before module execution begins (preload), or loadable only when referred to at run time (load-on-call).

mouse: In SAA usage, a device that a user moves on a flat surface to position a pointer on the screen. It allows a user to select a choice or function to be performed or to perform operations on the screen, such as dragging or drawing lines from one position to another.

MOUSE$: Character-device name reserved for a mouse.

MP-unsafe: Does not provide the necessary serialization to run on more than one CPU at a time. For example, a driver will be MP unsafe if it relies upon priorities between threads for accessing shared resources, or uses the CLI/STI method for protecting resources like semaphores or memory.

MP-safe: Provides the necessary serialization to run properly in a system with greater than one processor. Does not use invalid UP serialization techniques. For example, a driver will be MP safe if it does not rely upon priorities between threads for accessing shared resources, or use the CLI/STI method for protecting resources like semaphores or memory.

MP-exploitive: Provides proper MP serialization techniques which allow multiple threads to run concurrently on more than one CPU.

multiple-choice selection: In SAA Basic Common User Access architecture, a type of field from which a user can select one or more choices or select none. See also check box. Contrast with extended-choice selection.

multiple-line entry field: In SAA Advanced Common User Access architecture, a control into which a user types more than one line of information. See also single-line entry field.

multitasking: The concurrent processing of applications or parts of applications. A running application and its data are protected from other concurrently running applications.

mutex semaphore: (Mutual exclusion semaphore). A semaphore that enables threads to serialize their access to resources. Only the thread that currently owns the mutex semaphore can gain access to the resource, thus preventing one thread from interrupting operations being performed by another.

muxwait semaphore: (Multiple wait semaphore). A semaphore that enables a thread to wait either for multiple event semaphores to be posted or for multiple mutex semaphores to be released. Alternatively, a muxwait semaphore can be set to enable a thread to wait for any ONE of the event or mutex semaphores in the muxwait semaphore's list to be posted or released.