National Instruments NI-VXI User Manual

Page 133

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Glossary

NI-VXI User Manual

G-10

© National Instruments Corporation

N

NI-VXI

The National Instruments bus interface software for VME/VXIbus
systems.

nonprivileged access

One of the defined types of VMEbus data transfers; indicated by
certain address modifier codes. Each of the defined VMEbus address
spaces has a defined nonprivileged access mode.

NULL

A special value to denote that the contents (usually of a pointer) are
invalid or zero.

O

octal

Numbering system with base 8, using numerals 0 to 7.

P

parse

The act of interpreting a string of data elements as a command to
perform a device-specific action.

peek

To read the contents.

pointer

A data structure that contains an address or other indication of storage
location.

poke

To write a value

ppm

Parts per million

privileged access

See Supervisory Access.

propagation

Passing of signal through a computer system.

protocol

Set of rules or conventions governing the exchange of information
between computer systems.

Q

query

Like command, causes a device to take some action, but requires a
response containing data or other information. A command does not
require a response.

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