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UMA Measurement Layer Interface (MLI)
Copyright © 1997 The Open Group



Term used in this specification for referencing the American Standard Code for Interchange of Information: 8-bit (128-character) code set.


Abstract Syntax Notation One / Basic Encoding Rules - The ASN.1 language describes all abstract syntaxes in the OSI architecture. An abstract syntax is a named group of types. BER, the Basic Encoding Rules, is a transfer syntax used to communicate data between open systems. It includes those aspects of the rules used in the formal specification of data which embody bgcolor="#FFFFFF" a specific representation of that data. BER is capable of encoding any abstract syntax that can be described using ASN.1.


Application Program Interface - In general, a standard interface for programmatic access to services; MLI, a service API for UMA, is defined in this document.

Collection Interval

The time between successive captures of a specific set of data items. The term interval is also used to mean the data for a collection interval having a certain time stamp and duration.

Constructed Workload

A named workload data collection that results from a joint specification of any one or more of: Multiple class/subclass specifications, a granularity/summarization specification, an instance or UMAWorkInfo filtering specification, a complement workload specification.


Data Capture Interface - A standard UMA interface to access data sources such as kernel and subsystem data structures, hardware dependent data, and data which is event-generated.

Data Capture Layer

A UMA entity concerned with the collection of raw data from the operating system kernel and from other sources. Data is considered collected when it exists assembled into data structures of predefined class and subclass in storage controlled by services contained in the measurement model.

Data Acquisition Node

A physical entity (for example, a processor) that executes a UMA Data Capture and a UMA Data Services Layer.

Data Class

The general system measurement entity to be collected. For example, the data classes for UMA include system configuration information, processor and memory usage information, and other like categories.1

Data Provider

A logical entity in the Data Capture Layer that makes data available to UMA and its users, usually through the DCI.

Data Services Layer

The layer responsible for data distribution to measurement applications (which use the MLI for archival data storage), management of services and resources required for distributed measurement access and control, measurement requesting, and data format transformations required for recording and transmission.

Data Subclass

A specific grouping of data within a data class. Each data class may have several data subclasses. For instance, the Data Pool class processor contains subclasses such as Global Measured Processor Times and Global System Call Counters, etc.

Event Data

In the context of UMA, this represents the reporting of one or more system events (for example, process termination, creation, signal delivery, logon, etc.).


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

Measurement Application Layer

This functional layer contains the application primitives and tools used to report currently captured and archival performance data to the end-user (or to an automated stand-in). These applications are called Measurement Application Programs (MAPs).

Measurement Application Node

A physical entity that executes a MAP and a UMA Data Services Layer.


Measurement Application Program

Measurement Control Layer

The layer responsible for managing the capture of data, including its synchronisation, and for providing any necessary buffer or queue management for data assembled by the data capture mechanism.

Measurement Interval

A continuous time interval during which measurement activity and reporting is requested by a MAP.


In UMA, a basic unit of control or data information. Each UMA message contains a header portion which identifies the class and subclass of the information contained in the rest of the message.


Measurement Application Program - A UMA-based application program providing end-user services.


Measurement Layer Interface - The MLI comprises the Application Programming Interface (API) for UMA, and the management of UMA message transport.

Presumed Location (UMADS)

The location of historical data for a node that UMA determines through administrative policy.

Recent Data Facility

A UMA storage entity that caches the most current data captured by DCL data providers.

Regular Expression

In the context of the MLI, a text matching pattern constructed according to the rules described for Basic Regular Expressions (BREs) in the System Interface (XSH) CAE Specification (see reference XSH).

Reporting Interval

The union of one or more contiguous collection intervals to be seen by a MAP or by UMADS. Thus the reporting interval may be identical to a collection interval or it may have a duration that is (nominally) a multiple of the collection interval duration.

Sampling Interval

The time between successive samples during data capture.


In UMA, a logical communications channel between a MAP and the UMA facility. A MAP can establish multiple concurrent sessions.

Trace Data

In the context of UMA, reported trace data is data for a set of selected related events.


UMA Data Unit - The contents of a UMA API message. The UDU consists of a header portion and either a control segment or one or more data segments.


Universal Measurement Architecture - A common, flexible measurement control and data delivery mechanism.


UMA Data Storage - An archive that stores historical performance, resource usage, and accounting information. (In UMA, historical data is that for which the time of capture is earlier than time now.)


Data classes and subclasses for the Universal Measurement Architecture are described in the accompanying document Data Pool Definitions (see reference DPD).

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