Compaq ACMS for OpenVMS
Getting Started

task: In ACMS, a unit of work that performs a specific function and can be selected for processing by a terminal user or another task. Every task belongs to a task group. Some tasks are defined in the task group they belong to; other tasks have separate task definitions. In either case, they are defined with ADU. The work of a task can be defined as a single processing step or a block step, which consists of a series of exchange and processing steps.

See also exchange step, multiple-step task, processing step, single-step task, and task group.

task attributes: The part of a task definition that tells ACMS the characteristics for the task as a whole, such as what workspaces to use.

task definition: In ACMS, the specification of the steps involved in the exchange of data between a user and the application, and in the processing of data against a database or file. You write a task definition using the task definition language.

task element: See queued task element.

task group: One or more ACMS tasks that have similar processing requirements and that are gathered together so they can share resources. A task group definition, created with ADU, defines the servers used by the tasks that belong to the group. It also defines other characteristics and requirements for the tasks in the group, such as workspaces, request libraries, and message files.

See also task group database (TDB) and task group definition.

task group database (TDB): In ACMS, a binary file containing information derived from task and task group definitions. The Task Debugger uses the TDB when debugging tasks; ADU uses the TDB when building an application database. ACMS also uses the TDB to execute a task.

The TDB is created as a result of building a task group definition with ADU. Task group database files have the default file type .TDB.

task group definition: In ACMS, specifies the processing requirements and application resources shared by a group of tasks. The task group definition can include information about shared procedures, workspaces, servers, and messages. You write a task group definition using ADU. After creating the definition, you use ADU to build the task group database, which is the binary version of the definition file.

task instance: In ACMS, the occurrence of the processing of a task. Each selection of a task is a task instance. Every task instance is given a unique identifier by the ACMS run-time system.

See also task.

task I/O: In ACMS, the communication between a task submitter and a task instance. This communication can consist of OpenVMS terminal I/O, DECforms requests, TDMS requests, stream I/O, or I/O with other terminal or nonterminal interfaces using the Request Interface or Systems Interface.

See also request, Request Interface, Systems Interface, and task instance.

task queue: An area of storage where transactions can be placed as queued task elements for deferred processing. A task queue is created and managed using the ACMS Queue Manager Utility. Queued task elements are placed in the queue using the ACMS$QUEUE_TASK programming service and removed from the queue by the ACMS Queued Task Initiator.

See also queued task element, Queued Task Initiator, queued task services, queuing facility, and Queue Manager Utility.

task selection string: In ACMS, the string of characters a terminal user types, in addition to or in place of a selection keyword or number, when making a selection from a menu.

task step: See step.

task submitter: Any authorized ACMS user who selects tasks for processing, provides input for that processing, and receives the results of that processing. Task submitters must also be authorized OpenVMS users.

task workspace: A workspace used mainly to pass information between steps in an ACMS multiple-step task. A task workspace is allocated when a terminal user starts a task, and keeps its contents only for the duration of the task instance.

See also multiple-step task and task instance.

TDB: See task group database.

TDMS: See Terminal Data Management System.

Terminal Data Management System (TDMS): A transaction processing product that uses forms to collect and display information on the terminal. TDMS provides data independence by allowing data used in an application to be separated from the application program. ACMS multiple-step tasks use TDMS services to manage terminal input and output.

See also multiple-step task.

Terminal Subsystem Controller (TSC): The process that controls which terminals have access to ACMS, controls the creation/deletion of Command Processes, and assigns terminals to Command Processes.

termination procedure: A procedure that closes files and releases databases. Termination procedures run when a server process is run down.

TP monitor: See transaction processing monitor.

transaction: See database transaction and distributed transaction.

transaction exception: An error that causes a distributed transaction to fail.

transaction manager: In a distributed transaction, the DECdtm transaction coordinator that communicates with the resource managers and implements the two-phase commit protocol.

transaction processing (TP): An environment that addresses large, corporate-level applications that support many users for critical business functions. In a transaction processing application, many users simultaneously perform predefined (query and update) functions on a collection of shared data, generally a database. Results are usually expected immediately (real time).

transaction processing (TP) monitor: The component of a transaction processing system that manages access to the CPU, functioning like a specialized operating system within your operating system. A TP monitor can include utilities for terminal and forms management, data management, network access, authorization and security, and transaction restart/recovery. ACMS is a TP monitor.

TSC: See Terminal Subsystem Controller.

two-phase commit (2PC) protocol: A protocol used to synchronize the commit actions of multiple, independent resource managers. The protocol has a prepare phase, in which each resource manager indicates its willingness to commit; and a commit phase, in which resource managers, when instructed by the transaction manager, either commit and roll forward, or abort and roll back.

In a two-phase commit, either all resource managers commit the distributed transaction or all roll it back; the distributed transaction cannot be committed by some participants and rolled back by others.

UDU: See User Definition Utility.

UIC: See user identification code.

unique name: A designation assigned to a component, such as a task, that is used to identify that component within and across definitions.

user definition file: A file, created and maintained with the ACMS User Definition Utility (UDU), that contains a list of users authorized to access ACMS.

User Definition Utility (UDU): The ACMS tool for authorizing ACMS users and defining characteristics of those users.

user identification code (UIC): A code identifying an OpenVMS user by a group number or name and a member number or name separated by a comma and enclosed in brackets.

user interface: In a transaction processing system, the data input element. The user interface usually includes a presentation service, such as DECforms.

user name: A designation assigned to an OpenVMS user to identify that user. Also the name a terminal user enters to log in to OpenVMS and sign in to ACMS.

user request procedure (URP): A procedure that replaces a TDMS request in an exchange step and performs I/O to the user's device. The ACMS Request Interface (RI) executes URPs.

See also Request Interface.

user workspace: In ACMS, a workspace, defined as an attribute of a task group, that holds information about a terminal user. A user workspace is created the first time a terminal user starts a task that refers to it. ACMS keeps a separate copy of a user workspace for each user, and saves the contents of the workspace until the user exits from ACMS.

See also group workspace, task group, and workspace.

viewports: User-defined rectangular areas of a DECforms display. For a panel to be visible, it must be associated with a viewport.

workspace: In ACMS, a buffer used to save variable context between steps and tasks. Workspace descriptions are stored in a CDD dictionary. A workspace can also hold application parameters and status information. Workspaces are passed to step procedures and tasks as parameters.

See also group workspace, system workspace, task workspace, and user workspace.