View source for DDK Glossary - R

;radio button
: (1) A control window, shaped like a round button on the screen, that can be in a checked or unchecked state. It is used to select a single item from a list. Contrast with check box.
: (2) In SAA Advanced Common User Access architecture, a circle with text beside it. Radio buttons are combined to show a user a fixed set of choices from which only one can be selected. The circle is partially filled when a choice is selected.

;RAS
: Reliability, availability, and serviceability.

;raster
: (1) In computer graphics, a predetermined pattern of lines that provides uniform coverage of a display space. (T)
: (2) The coordinate grid that divides the display area of a display device. (A)

;read-only file
: A file that can be read from but not written to.

;Read-Only Memory Basic Input/Output System (ROM-BIOS)
: Microcode in read-only memory that controls basic input/output operations such as interactions with cassettes, diskette drives, hard disk drives, and the keyboard. Abbreviated as ROM BIOS. See also [[DDK_Glossary_-_B|BIOS]], [[DDK_Glossary_-_N|NetBIOS]].
:;Note: ROM BIOS allows the user to write programs and add or remove devices without concern for characteristics such as device addresses.

;real mode
: In the OS/2 operating system, a method of program operation that does not limit or prevent access to any instructions or areas of storage. The operating system loads the entire program into storage and gives the program access to all system resources. Contrast with [[DDK_Glossary_-_P|protect mode]].

;realize
: To cause the system to ensure, wherever possible, that the physical color table of a device is set to the closest possible match in the logical color table.

;recursive routine
: A routine that can call itself, or be called by another routine that was called by the recursive routine.

;reentrant
: The attribute of a program or routine that allows the same copy of the program or routine to be used concurrently by two or more tasks.

;reference phrase
: (1) A word or phrase that is emphasized in a device-dependent manner to inform the user that additional information for the word or phrase is available.
: (2) In hypertext, text that is highlighted and preceded by a single-character input field used to signify the existence of a hypertext link.

;reference phrase help
: In SAA Common User Access architecture, highlighted words or phrases within help information that a user selects to get additional information.

;refresh
: To update a window, with changed information, to its current status.

;region
: A clipping boundary in device space.

;register
: A part of internal storage having a specified storage capacity and usually intended for a specific purpose. (T)

;remote file system
: A file-system driver that gains access to a remote system without a block device driver.

;removable-media indicator
: A flag (bit) indicating that a device permits media removal.

;resource
: The means of providing extra information used in the definition of a window. A resource can contain definitions of fonts, templates, accelerators, and mnemonics; the definitions are held in a resource file.

;resource file
: A file containing information used in the definition of a window. Definitions can be of fonts, templates, accelerators, and mnemonics.

;restore
: To return a window to its original size or position following a sizing or moving action.

;resurrection
: The Presentation Manager event that occurs when switched back from a full-screen DOS or WIN-OS/2 session.

;retained graphics
: Graphic primitives that are remembered by the Presentation Manager interface after they have been drawn. Contrast with [[DDK_Glossary_-_N|nonretained graphics]].

;RETF
: Return far.

;return code
: (1) A value returned to a program to indicate the results of an operation requested by that program.
: (2) A code used to influence the execution of succeeding instructions. (A)

;reverse video
: (1) A form of highlighting a character, field, or cursor by reversing the color of the character, field, or cursor with its background; for example, changing a red character on a black background to a black character on a red background.
: (2) In SAA Basic Common User Access architecture, a screen emphasis feature that interchanges the foreground and background colors of an item.

;REXX Language
: Restructured Extended Executor. A procedural language that provides batch language functions along with structured programming constructs such as loops, conditional testing, and subroutines.

;RGB
: (1) Color coding in which the brightness of the additive primary colors of light, red, green, and blue, are specified as three distinct values of white light.
: (2) Pertaining to a color display that accepts signals representing red, green, and blue.

;roman
: Relating to a type style with upright characters.

;root segment
: In a hierarchical database, the highest segment in the tree structure.

;ROP
: Raster operation.

;round-robin scheduling
: A process that allows each thread to run for a specified amount of time.

;RTC
: Real-Time Clock.

;run time
: (1) Any instant at which the execution of a particular computer program takes place. (T)
: (2) The amount of time needed for the execution of a particular computer program. (T)
: (3) The time during which an instruction in an instruction register is decoded and performed. Synonym for execution time.

[[Category:Glossary]]