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User Exit
A user exit is a subroutine invoked by a software package for a predefined event in the execution of the package. In some cases the exit is specified by the installation when configuring the package while in other cases the users of the package can substitute their own subroutines in place of the default ones provided by the package vendor to provide customized functionality. In some cases security controls restrict exits to authorized users, e.g., EXCP appendages in MVS. The earliest use of this term involved operating systems to let customized code temporarily take control when a pre-designated event occurred.IBM term: OS/MFT, MVT A more typical use is replacing the user exits provided by a sort/merge package, whereby the user program provides its own subroutines for comparing records. The procedures provided by the user take the place of the default routines (usually stubs that do nothing but return to their caller) provided by the package vendor. Procedures provided as user ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subroutine
In computer programming, a function (also procedure, method, subroutine, routine, or subprogram) is a callable unit of software logic that has a well-defined interface and behavior and can be invoked multiple times. Callable units provide a powerful programming tool. The primary purpose is to allow for the decomposition of a large and/or complicated problem into chunks that have relatively low cognitive load and to assign the chunks meaningful names (unless they are anonymous). Judicious application can reduce the cost of developing and maintaining software, while increasing its quality and reliability. Callable units are present at multiple levels of abstraction in the programming environment. For example, a programmer may write a function in source code that is compiled to machine code that implements similar semantics. There is a callable unit in the source code and an associated one in the machine code, but they are different kinds of callable units with different impl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM Configuration Management Version Control (CMVC)
Configuration Management Version Control (CMVC) is a software package that serves as an object repository, and performs software version control, configuration management, and change management functions. Architecture * This was a client-server based system, with command-line and graphical clients for several platforms and servers available for several flavors of Unix. * A relational database was used to keep tracking information but a separate Source Control Manager such as Source Code Control System (SCCS) or PVCS was used to maintain version history for each file. The filenames for these files are actually stored in the relational database - as a result, filenames in the SCCS tree are numeric ids. Concepts * Files are created and associated with Components. * Components form a directed graph where each Component can have several parents. Components are a logical grouping mechanism allowing Files to be grouped together without regard to their physical pathnames (unlike dir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Library (computing)
In computing, a library is a collection of System resource, resources that can be leveraged during software development to implement a computer program. Commonly, a library consists of executable code such as compiled function (computer science), functions and Class (computer programming), classes, or a library can be a collection of source code. A resource library may contain data such as images and Text string, text. A library can be used by multiple, independent consumers (programs and other libraries). This differs from resources defined in a program which can usually only be used by that program. When a consumer uses a library resource, it gains the value of the library without having to implement it itself. Libraries encourage software reuse in a Modular programming, modular fashion. Libraries can use other libraries resulting in a hierarchy of libraries in a program. When writing code that uses a library, a programmer only needs to know how to use it not its internal d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hook (computer Science)
In computer programming, the term hooking covers a range of techniques used to alter or augment the behaviour of an operating system, of applications, or of other software components by intercepting function calls or messages or events passed between software components. Code that handles such intercepted function calls, events or messages is called a hook. Hook methods are of particular importance in the template method pattern where common code in an abstract class can be augmented by custom code in a subclass. In this case each hook method is defined in the abstract class with an empty implementation which then allows a different implementation to be supplied in each concrete subclass. Hooking is used for many purposes, including debugging and extending functionality. Examples might include intercepting keyboard or mouse event messages before they reach an application, or intercepting operating system calls in order to monitor behavior or modify the function of an applicatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Callback (computer Science)
In computer programming, a callback is a Function (computer programming), function that is stored as data (a Reference (computer science), reference) and designed to be called by another function often ''back'' to the original Abstraction (computer science), abstraction layer. A function that accepts a callback Parameter (computer programming), parameter may be designed to call back before Return statement, returning to its caller which is known as ''Synchronization (computer science), synchronous'' or ''blocking''. The function that accepts a callback may be designed to store the callback so that it can be called back after returning which is known as ''asynchronous'', ''Non-blocking algorithm, non-blocking'' or ''deferred''. Programming languages support callbacks in different ways such as function pointers, Lambda (programming), lambda expressions and block (programming), blocks. A callback can be likened to leaving instructions with a tailor for what to do when a suit is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SAP AG
Sap is a fluid transported in the xylem cells (vessel elements or tracheids) or phloem sieve tube elements of a plant. These cells transport water and nutrients throughout the plant. Sap is distinct from latex, resin, or cell sap; it is a separate substance, separately produced, and with different components and functions. Honeydew (secretion), Insect honeydew is called sap, particularly when it falls from trees, but is only the remains of eaten sap and other plant parts. Types of sap Saps may be broadly divided into two types: xylem sap and phloem sap. Xylem sap Xylem sap (pronounced ) consists primarily of a watery solution of plant hormone, hormones, dietary mineral, mineral elements and other nutrients. Transport of sap in xylem is characterized by movement from the roots toward the leaf, leaves. Over the past century, there has been some controversy regarding the mechanism of xylem sap transport; today, most plant scientists agree that the cohesion-tension theory be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RACF
Resource Access Control Facility (RACF) is an IBM software security product that provides access control and auditing functions for the z/OS and z/VM operating systems. RACF was introduced in 1976. Originally called RACF it was renamed to z/OS Security Server (RACF), although many mainframe professionals still refer to it as RACF. Its main features are: * Identification and verification of a user via user id and password check (authentication) * Identification, classification and protection of system resources * Maintenance of access rights to the protected resources (access control) * Controlling the means of access to protected resources * Logging of accesses to a protected system and protected resources (auditing) RACF establishes security policies rather than just permission records. It can set permissions for file patterns—that is, set the permissions even for files that do not yet exist. Those permissions are then used for the file (or other object) created at a late ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Z/OS
z/OS is a 64-bit operating system for IBM z/Architecture mainframes, introduced by IBM in October 2000. It derives from and is the successor to OS/390, which in turn was preceded by a string of MVS versions.Starting with the earliest: * OS/VS2 Release 2 through Release 3.8 * MVS/System Extensions (MVS/SE) * MVS/System Product (MVS/SP) Version 1 * MVS/System Product Version 2 (MVS/Extended Architecture, MVS/XA) * MVS/System Product Version 3 (MVS/Enterprise Systems Architecture, MVS/ESA) * MVS/ESA SP Version 4 * MVS/ESA SP Version 5 Like OS/390, z/OS combines a number of formerly separate, related products, some of which are still optional. z/OS has the attributes of modern operating systems but also retains much of the older functionality that originated in the 1960s and is still in regular use—z/OS is designed for backward compatibility. Major characteristics z/OS supportsSome, e.g., TSO/E, are bundled with z/OS, others, e.g., CICS, are separately priced. stable ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hierarchical Storage Management
Hierarchical storage management (HSM), also known as tiered storage, is a Computer data storage, data storage and data management technique that automatically moves data between high-cost and low-cost data storage media, storage media. HSM systems exist because high-speed storage devices, such as solid-state drive arrays, are more expensive (per byte stored) than slower devices, such as hard disk drives, optical discs and magnetic tape drives. While it would be ideal to have all data available on high-speed devices all the time, this is prohibitively expensive for many organizations. Instead, HSM systems store the bulk of the enterprise's data on slower devices, and then copy data to faster disk drives when needed. The HSM system monitors the way data is used and makes best guesses as to which data can safely be moved to slower devices and which data should stay on the fast devices. HSM may also be used where more robust storage is available for long-term archiving, but this is slo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Job Entry Subsystem 2/3
The Job Entry Subsystem (JES) is a component of IBM's MVS ( MVS/370 through z/OS) mainframe operating systems that is responsible for managing batch workloads. In modern times, there are two distinct implementations of the Job Entry System called JES2 and JES3. They are designed to provide efficient execution of batch jobs. Starting with z/OS 3.1, released in September 2023, IBM z/OS no longer includes JES3, and comes with JES2 only – JES3 sites must either migrate to JES2, or license JES3plus from Phoenix Software International, who has taken over future support and development of JES3 from IBM. Job processing is divided into several phases to provide parallelism through pipelining. These phases include input processing where jobs are read and interpreted, the execution phase where jobs run, and output processing where job output is printed or stored on DASD. Jobs that are in the same phase of execution are usually said to reside on a particular queue; for example, jobs th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kornshell
KornShell (ksh) is a Unix shell which was developed by David Korn (computer scientist), David Korn at Bell Labs in the early 1980s and announced at USENIX Annual Technical Conference, USENIX on July 14, 1983. The initial development was based on Bourne shell source code. Other early contributors were Bell Labs developers Mike Veach and Pat Sullivan, who wrote the Emacs and Vi (text editor), vi-style line editing modes' code, respectively. KornShell is backward-compatible with the Bourne shell and includes many features of the C shell, inspired by the requests of Bell Labs users. Features KornShell complies with POSIX#POSIX.2, POSIX.2, Shell and Utilities, Command Interpreter (IEEE Std 1003.2-1992.) Major differences between KornShell and the traditional Bourne shell include: * Job control (Unix), job control, alias (command), command aliasing, and command history designed after the corresponding C shell features; job control was added to the Bourne Shell in 1989 * a choice ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CICS
IBM CICS (Customer Information Control System) is a family of mixed-language application servers that provide online business transaction management, transaction management and connectivity for applications on IBM mainframe systems under z/OS and z/VSE. CICS family products are designed as middleware and support rapid, high-volume online transaction processing. A CICS ''transaction'' is a unit of processing initiated by a single request that may affect one or more objects. This processing is usually interactive (screen-oriented), but background transactions are possible. CICS Transaction Server (CICS TS) sits at the head of the CICS family and provides services that extend or replace the functions of the operating system. These services can be more efficient than the generalized operating system services and also simpler for programmers to use, particularly with respect to communication with diverse terminal devices. Applications developed for CICS may be written in a variet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
