R

RAID
acronym for redundant array of inexpensive (or independent) disks; secondary storage system that uses multiple disk drives, which allows multiple write (data storage) operations to occur at the same time.

RAM
acronym for random-access memory, the part of memory that can be accessed directly and used for temporary storage of data and programs.

ROM
acronym for read-only memory, a special memory area containing permanent instructions that the computer uses when it is turned on.

Rapid application development
tools used to assist in developing components of a system.

Read/write head
a device that can either access (read) data stored magnetically or save (write) data onto magnetic media.

Reading
accessing data or instructions; a nondestructive process.

Receiver
the recipient of a message being communicated.

Record
an individual row in a file containing data about one person, place, or thing based on designated items of interest (fields).

Redundancy
unnecessary duplication of data.

Reel-to-reel magnetic tape
sequential access storage system that uses two reels, with magnetic tape wound from one reel to the other during use.

Refresh rate
how often the screen image is redrawn.

Register
a temporary area used during execution of an instruction to hold needed items, such as data, instructions, and addresses.

Relational structure
database structure that organizes data into a two-dimensional table, with a capability of linking data in one table with data in another table.

Report generator
a fourth-generation language capability that allows reports to be created somewhat automatically, without writing a series of programs.

Requirements determination
system development phase in which the current system is analyzed and system users' needs and constraints are identified.

Router
device that selects the channel (route) to use for transmission of a message.