HP QMS 1660 - Manual (Page 277)

Raster Graphics
Glossary G-13
Printer Driver
A printer driver is a program that translates the file you are printing into a
language that the printer understands. Usually, the printer driver is installed
within an application.
PROM
An acronym for Programmable Read-Only Memory. A storage device that
can be programmed by electrical pulses, a PROM does not lose its memory
when the printer is powered off. See also
EEPROM, EPROM.
Protocol
A set of rules or standards designed to enable computers and other devices
to connect to one another and to exchange information.
Queue
A list of documents waiting to be printed.
RAM
An acronym for Random Access Memory, the memory your printer uses to
perform tasks. It can be written to and read from. Once a task is complete,
the memory is free again to be used for another file. This memory is volatile,
so if your printer loses power while a file is being sent, you must resend the
file. The number and type of features you can run simultaneously on your
printer depend on the amount of RAM available and how that RAM is
distributed. RAM can be increased by adding SIMMs. See also
SIMM.
RAM Disk
Also called a virtual disk. The RAM disk is an area of RAM that is used to
simulate an additional hard disk. Data can be written to and read from a
RAM disk more quickly than a hard disk, but a RAM disk loses any
information stored on it when the printer’s power is turned off. The frame
buffer and spooling buffer are RAM disk clients. See also
RAM.
Raster Graphics
The system of forming graphics using a bitmap, or grid of small dots, is
called raster graphics. The term “raster” denotes the Cartesian grid system
in which the dots are arranged. Bitmaps can define images, shapes, or
characters created with a specific number of dots per inch. See also
bitmap.