NonStop System Glossary

Open Systems Interconnection Layer 2
The data-link control level of the Open Systems Interconnection (OSI) model, composed of
asynchronous or minimal line control protocols, byte-oriented or character-oriented protocols, and
bit-synchronous or bit-oriented protocols. Data link protocols can be defined in terms of method of
access of data, link relationship of stations, error detection scheme, error recovery, message
formatting, logical half-duplex or full-duplex operation, code, and machine transparency.
Open Systems Interconnection (OSI)
A seven-layer network architecture model defined by the International Organization for
Standardization (ISO). The two lowest layers deal with the physical connections and their protocols.
The five upper layers deal with network services, such as network file transfers and access to remote
databases.
operating system
See HP NonStop operating system.
operating system image
See OSIMAGE.
operational environment
The conditions under which your system performs. These conditions include the devices and
communications lines that are made active and the system and application processes that are
started at system startup.
operator
1. A symbol, such as an arithmetic or conditional operator, that performs a specific operation
on operands.
2. In Network Control Language (NCL), a lexical element used for working on terms in expressions.
The five types of operators are parenthetical, arithmetic, Boolean, relational, and string.
3. For a NonStop server, the person or program responsible for day-to-day monitoring and
maintenance tasks associated with the NonStop operating system and the hardware of a NonStop
node. The operator issues commands to subsystems; retrieves, examines, and responds to event
messages; or does any combination of those things. See also local operator. Contrast with
administrator.
4. For a UNIX system, any interactive user of that system.
operator message
A message, intended for an operator, that describes a significant event on a NonStop server. An
operator message is the displayed-text form of an Event Management Service (EMS) event message.
option
In a UNIX or Open System Services (OSS) command, a flag and its parameters or a flag without
parameters.
ordinary dynamic-link library (ordinary DLL)
A dynamic-link library (DLL) or shared run-time library (SRL) that is not public. The code file is found
at run time and can be provided by the user. Contrast with public dynamic-link library (public DLL).
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