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UMA Data Capture Interface (DCI)
Copyright © 1997 The Open Group



Application Programming Interface. A standard interface for program access to a set of services. The DCI API is defined in this document.

Data Capture Interface

The API for the Data Capture Layer.

Data Capture Layer

The lowest layer in the UMA metrics architecture. It is concerned with the collection of raw data from the system.


Data Capture Interface

DCI server

An abstraction provided by the DCI. The DCI server provides a set of services to metrics providers and consumers.


Data Capture Layer

event, event metric

An event is a metric. An occurrence of some activity of interest to a metrics consumer (for example, thread termination).


abbreviation used in this specification for the term internationalization (which has 18 letters between its first and last letters).


A single measurement. Metrics have unique identifiers defined through the metrics name space. A metric is either a polled metric (indicating some statistic or other data) or it is an event. Polled metrics have metric values that can be obtained by querying the DCI. Events may have associated data returned with the event when it occurs. (See Events and Event Data Attributes ).

metric class

Metrics are grouped into metric classes. Classes are organised in a hierarchy. A metric class holds no metric values. It is simply a placeholder in the namespace. It should be viewed as a template.

metric class instance

Metric values are associated with instantiations of metric classes. For example, there could be a class for per-thread statistics; associated with this class could be many instances, each one identified by its thread id. A particular thread's statistics would be available by querying the DCI for that specific metric class instance.

metrics consumer

Any application which needs to import metrics.

metrics provider

Any subsystem which has metrics to export. The subsystem can either be the operating system or applications.

metric value

The value of a polled metric is referred to as a metric value. Note that metrics that are events do not have metric values.


The Measurement Layer Interface. An upper level service, one of the possible DCI consumers, that provides a measurement control and data delivery mechanism.

multiprocessor system

Any machine which contains more than one processor but appears to the user to be running a single operating system.


An eight bit unit of storage.

operating system

Privileged software which controls hardware resources.


Performance Management Working Group. The group which has specified the Universal Measurement Architecture.

polled metric

A polled metric is a metric. It typically corresponds to a numerical count of some system activity, some statistic, or possibly some configuration information (for example, the number of processors).


That part of an operating system concerned with controlling access to information.

system space

An address space in which privileged programs, such as the operating system, are run.

user space

An address space in which unprivileged programs are run. Examples of such programs are applications or system services which do not require direct access to hardware resources.


Universal Measurement Architecture. The collection of the DCI, Data Pool and MLI that provides a complete performance measurement architecture.
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