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UMA Data Pool Definition (DPD)
Copyright © 1997 The Open Group



In the context of this DPD specification, this term means that any shared resource size is divided by the number of processes sharing it.


Application Program Interface. A standard interface for program access to set of services. The API for UMA is the Measurement Level Interface (or MLI).


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.

Collection Interval

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


Connection Oriented Network Service.


"central processor unit": a set of one or more computational engines on which a system runs to provide computing services to applications. A cpu can be a single processor or a multiprocessor device.


Direct Access Storage Device (for example, disk).


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 UNIX kernel and 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 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. The UMA classes and subclasses are defined in this document.

Data Services Layer

A UMA entity responsible for data distribution to measurement applications using the MLI, for archival data storage, for management of services and resources required for distributed measurement access and control, for measurement requesting, and for 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 class "processor" contains subclasses such as "Global Measured Processor Times" and "Global System Call Counters", etc.

Disk Partition

A portion of a disk. A disk partition can contain a file system or a raw data structure such as swap space or raw database management space. To optimise disk performance, a file system is often comprised of several partitions spread across several disks. This includes a file system mounted on a logical volume, in which case the whole physical space allocated to a logical volume on a particular disk can be thought of as a partition.

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.).


Front End Processor.


Group Identifier of a process.


Input/Output Processor.


Interprocess communication.


The amount of physical memory used in kilobytes * the time occupying physical memory (user time + system time).


The Logical Volume Manager supports logical volumes by managing the disks in small chunks, usually 4 MB. A logical volume may span several disks, and its size may be increased without disturbing the file systems.

Measurement Application Layer

In the context of UMA, 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 application implementations are called Measurement Application Programs (MAPs).

Measurement Control Layer

A UMA entity 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 measurement application program (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.


Management Information Base.


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


New Queue Service.


Open Systems Interconnect.


Process Identifier.


Parent Process Identifier.


Performance Management Working Group. The working group, originally within UNIX International, now within the Computer Measurement Group, that developed the base document for this specification.


One of several computational engines that comprise a multiprocessor cpu. A single processor (uniprocessor) cpu has one processor.

Reporting Interval

The union of one or more contiguous collection intervals to be seen by a MAP. 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.


Simple Network Management Protocol


UNIX System V Interface Definition.


The hardware and software associated with a single running image of the operating system.

Trace Data

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


User Identifier of a process.


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.


Virtual Memory.
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