VeriFone Omni 3200 Reference Manual page 174

Omni 3200 Reference Manual
C-4
CONFIG.SYS File. A special keyed file that is stored in terminal
memory and which contains system and application configuration
parameters. Each record in the CONFIG.SYS file is identified by an
alphanumeric key. You can modify CONFIG.SYS records using the
keyed file editor. See 'Keyed File Editor'.
Control Character. A character that when typed at a keyboard or
sent to a peripheral device is treated as a signal to control operating
functions. Also, a character that initiates, modifies, or stops a control
operation.
CPU. Abbreviation for 'central processing unit'. The principal
operating part of a computer system that controls the interpretation
and execution of instructions stored in memory.
Cyclic Redundancy Check. Also called 'Cyclic Redundancy
Code' or 'CRC'. The most widely used error-detection code for data
transfers. In a block data transfer, extra digits are appended to each
block to provide a means of checking the data for errors that may
have occurred during transmission.
Data. Information prepared, often in a particular format, for a
specific purpose. Data is to be distinguished from applications
program instructions. In a POS terminal, application files and data
files are stored in non-volatile memory, or SRAM.
Data Entry. The process of using a keyboard, card reader, or other
device to input data directly into a system.
Data Packets. A group of bits of fixed maximum size and well-
defined format that is switched and transmitted as a composite whole
through a packet switching network. Any message that exceeds the
maximum size is partitioned and carried as several packets. The
packets are formed by the controller in the sending data terminal and
the data is extracted and reassembled by the controller at the
receiving end.