IBM OS/390 manual System management facilities SMF. See SMF

Storage Management Subsystem (SMS). A component of MVS/DFP that is used to automate and centralize the management of storage by providing the storage administrator with control over data class, storage class, management class, storage group, and ACS routine definitions.

structured programming. A method for constructing programs using only hierarchically nested constructs each having a single entry and a single exit point.

Three types of control flow are used in structured programming: sequential, conditional, and iterative.

sublibrary. In VSE, a subdivision of a library. See also library.

subprogram. A program invoked by another program. Contrast with main program.

subroutine. A sequenced set of instructions or statements that may be used in one or more computer programs and at one or more points in a computer program. (3) A group of instructions that can be part of another routine or can be called by another program or routine.

subsystem. A secondary or subordinate system, usually capable of operating independently of, or asynchronously with, a controlling system.

supervisor. The part of a control program that coordinates the use of resources and maintains the flow of processing unit operations. See also system supervisor.

symbolic name. In a programming language, a unique name used to represent an entity such as a field, file, data structure, or label.

syntax. (1) The relationship among characters or groups of characters, independent of their meanings or the manner of their interpretation and use. (2) The rules governing the structure of a language.

syntax error. A compile-time error caused by incorrect syntax. See also semantic error.

sysplex. A multiple-MVS system environment that allows MCS consoles or extended MCS consoles to receive messages and send commands across systems.

system console. A console, usually equipped with a keyboard and display screen, that is used by an operator to control and communicate with a system.

system date. The date established for the system when it is started.

system generation (SYSGEN). The process of selecting optional parts of an operating system and of creating a particular operating system tailored to the requirements of a data processing installation.

system maintenance. The modification of a system to correct faults, to improve performance, or to adapt the system to a changed environment or changed requirements.

system management facilities (SMF). See SMF.

system-managed storage. Storage managed by the Storage Management Subsystem. SMS attempts to deliver required services for availability, performance, space, and security to applications. See also DFSMS environment.

system-managed volume. A DASD, optical, or tape volume that belongs to a storage group. Contrast with DFSMShsm-managed volume and DFSMSrmm-managed volume.

System Modification Program (SMP). A program used to install software and software changes on MVS systems.

system operator. An operator responsible for performing system- oriented procedures.

system programmer. A programmer who plans, generates, maintains, extends, and controls the use of an operating system with the aim of improving overall productivity of an installation.

system resources. Those resources controlled by the system, such as programs, devices, and storage areas that are assigned for use in jobs.

system software. Software that is part of or made available with a computer system and that determines how application programs are run; for example, an operating system. Contrast with application software.

system support. The continued provision of services and material necessary for the use and improvement of an implemented system.

SystemPac. A software package consisting of installed products for a ready-to-IPL system. Some of the products have been customized in response to information provided to IBM. A SystemPac can be used to install an MVS system for the first time or to replace an existing MVS system.

systems management. Functions in the application layer related to the management of Open Systems Interconnection resources and their status across all layers of the OSI architecture.

580VSE to OS/390 Migration Workbook