Commodore 128 Programmer's Reference Manual page 744

734 COMMODORE 128
0
Dimension: The property of an array that specifies the size and direction along an axis
in which the array elements are stored. For example, a two-dimensional array has
an X-axis for rows and a Y-axis for columns. See Array. j
Direct Connect Modem: A device that converts digital signals from a computer into wj
electronic impulses for transmission over telephone lines. Contrast with Acoustic
Coupler. \ |
Direct Mode: The mode of operation that executes BASIC commands immediately after JJ
the RETURN key is pressed. Also called Immediate Mode. See Command.
Disable: To turn off a bit, byte or specific operation of the computer. --■
Disk Drive: A random access, mass-storage device that saves and loads files to and j |
from a floppy diskette. ^
Disk Operating System: A program used to transfer information to and from a disk.
Often referred to as a DOS.
Duration: The length of time a musical note is played.
Electronic Mail, or E-Mail: A communications service for computer users in which
textual messages are sent to a central computer, or electronic "mailbox," and r~,
later retrieved by the addressee. i f
Enable: To turn on a bit, byte or specific operation of the computer.
Envelope Generator: Portion of the Commodore 128 that produces specific wave
forms (sawtooth, triangle, pulse width and noise) for musical notes. See Waveform. J j
EPROM: A PROM that can be erased by the user, usually by exposing it to ultraviolet U
light. Abbreviation for Erasable Programmable Read Only Memory. See PROM.
Error Checking or Error Detection: Software routines that identify, and often < [
correct, erroneous data. y
Execute: To perform the specified instructions in a command or program statement.
Expression: A combination of constants, variables or array elements acted upon by —
logical, mathematical or relational operators that return a numeric value. (
File: A program or collection of data treated as a unit and stored on disk or ^
tape.
Firmware: Computer instructions stored in ROM, as in a game cartridge. j |
Frequency: The number of sound waves per second of a tone. The frequency corre- U
sponds to the pitch of the audible tone.
Full-Duplex Mode: In this mode, two computers can transmit and receive data at the r~j
same time. I
Function: A predefined operation that returns a single value.
Function Keys: The four keys on the far right of the Commodore 128 keyboard. Each
key can be programmed to execute a series of instructions. Since the keys can be ] J
SHIFTed, you can create eight different sets of instructions. U
GCR: The abbreviation for Group Code Recording, a method of storing information on
a disk. The 1541 and 1571 disk drives can read, write and format GCR disks.
Graphic Characters: Nonalphanumeric characters on the computer's keyboard.
Graphics: Visual screen images representing computer data in memory (i.e., charac
ters, symbols and pictures).
Grid: A two-dimensional matrix divided into rows and columns. Grids are used to
design sprites and programmable characters.