Rockwell Automation 1770-M12 Mass Storage Systems - Manual (Page 68)

Glossary
Appendix E
EĆ3
Full–Duplex Line: A communication line used in transmission of data to and
from the central processing unit. A full–duplex line can carry data in both
directions (to and from) simultaneously. Contrast with half–duplex line.
Half–Duplex Line: A communication line used in transmission of data to and
from the central processing unit. A half–duplex line can carry data in either
direction (to or from), but in only one direction at a time.
Hardware: The electrical and mechanical devices that make up a computer
system. The equipment that is part of a computer system. Contrast with
software.
Information: Data that has been processed into a meaningful form. it adds to
a representation and tells the recipient something that was not known before.
information should be timely, accurate, and complete. Information reduces
uncertainty. Contrast with data.
Information System: A system that processes data into a meaningful form that
can be used by the recipient for decision–making purposes.
Intelligent Terminal: A computer–oriented terminal that has built–in data–
checking capabilities and a small memory. Special functions may also be built
into the terminal to handle certain kinds of transactions.
Interactive Computing: The type of processing in which the user of the
system communicates directly with the system to input data and instructions and
receive output. See on–line.
Interface: The boundary between two systems; a shared boundary between
two systems.
List Organization: A set of records that are stored in one order and linked
together in a different logical order by the insertion of pointers in each record.
In a list, the logical order or sequence of records is different from the physical
order.
Load: To place data into an internal register under program control. To place a
program from external storage into central memory under operator control.
Magnetic Disk: A secondary storage device. A circular disk, similar in
appearance to a phonograph record. Data can be recorded on the magnetic
surface of the disk. Several disks can be mounted together as a stack to create a
disk unit or disk pack. Data are written on or read from the surface as a drum
revolves a high speeds.
Master File: A permanent file of data pertaining to the history or current status
of a factor or entity of interest to an organization. A master file is periodically
updated to maintain its usefulness.
Micro–floppy: A 3 1/2 inch diskette protected in a hard plastic shell.