Open System Services Programmer's Guide

event A significant change in some condition in the system or network. An event can be an operational

error, notification of limits exceeded, request for action, notification of lines and other objects

becoming available, and so on. Note that an event is not always an error.

Event Management

Service (EMS)

A part of the Distributed Systems Management (DSM) product used to provide event collection,

event logging, and event distribution facilities. It provides for different event descriptions for

interactive and programmatic interfaces, lets an operator or application select specific

event-message data, and allows for flexible distribution of event messages within a system or

network.

executable and

linkable format

(ELF)

The common standard file format for an object file used for native code on NonStop systems.

feature test macro A symbol defined by the compiler to indicate the presence of some feature in the compilation.

FIFO A type of special file that is always read and written in a first-in, first-out manner.

FIFO special file See FIFO.

file An object to which data can be written or from which data can be read. A file has attributes

such as access permissions and a file type. In the Open System Services (OSS) environment, file

types include regular file, character special file, block special file, FIFO, and directory. In the

Guardian environment, file types include disk files, processes, and subdevices.

file descriptor The nonnegative integer that uniquely identifies a single open of a file to a running process. Each

file descriptor is associated with an open file description that contains data about the file.

file identifier In the Guardian environment, the portion of a filename following the subvolume name. In the

OSS environment, a portion of the internal information used to identify a file in the OSS file

system. The two identifiers are not necessarily equivalent. However, the same character sequence

can be used in both contexts if it satisfies the following conditions: it contains up to eight characters,

all of which are lower-case letters or decimal digits, and the first character is a letter.

file name A string of characters that uniquely identifies a file.

In the PC environment, file names for disk files normally have at least two parts (the disk name

and the file name); for example, B:MYFILE.

In the Guardian environment, disk file names include an Expand node name, volume name,

subvolume name, and file identifier; for example, \NODE.$DISK.SUBVOL.MYFILE.

In the OSS environment, a file is identified by a pathname; for example, /usr/john/workfile.