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VTAM
Virtual Telecommunications Access Method (VTAM) is the IBM subsystem that implements Systems Network Architecture (SNA) for mainframe environments. VTAM provides an application programming interface (API) for communication applications, and controls communication equipment such as adapters and controllers. In modern terminology, VTAM provides a communication stack and device drivers. History VTAM was introduced in 1974 after a series of delays as a major component of SNA along with the 370x Network Control Program (NCP) and Synchronous Data Link Control (SDLC). In IBM terminology, VTAM is an access method software allowing application programs to read and write data to and from external devices. It is called 'virtual' because it was introduced at the time when IBM was introducing virtual storage by upgrading the operating systems of the System/360 series to virtual storage versions. VTAM was supposed to be the successor to the older telecommunications access methods, such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Systems Network Architecture
Systems Network Architecture (SNA) is IBM's proprietary computer network, networking architecture, created in 1974. It is a complete protocol stack for interconnecting computers and their resources. SNA describes formats and protocols but, in itself, is not a piece of software. The implementation of SNA takes the form of various communications packages, most notably Virtual Telecommunications Access Method (VTAM), the mainframe computer, mainframe software package for SNA communications. History SNA was made public as part of IBM's "Advanced Function for Communications" announcement in September, 1974, which included the implementation of the SNA/SDLC (Synchronous Data Link Control) protocols on new communications products: *IBM 3767 communication terminal (printer) *IBM 3770 data communication system They were supported by IBM 3705 Communications Controller, IBM 3704/3705 communication controllers and their IBM Network Control Program, Network Control Program (NCP), and by Syste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DOS/360 And Successors
Disk Operating System/360, also DOS/360, or simply DOS, is the discontinued first member of a sequence of operating systems for IBM System/360, System/370 and later mainframes. It was announced by IBM on the last day of 1964, and it was first delivered in June 1966. In its time, DOS/360 was the most widely used operating system in the world. DOS versions BOS/360 The Basic Operating System (BOS) was an early version of DOS and TOS which could provide usable functionality on a system with as little as 8 KB of main storage and one 2311 disk drive. TOS/360 TOS/360 (Tape Operating System/360, not a DOS as such and not so called) was an IBM operating system for the System/360, used in the early days around 1965 to support the System/360 Model 30 and similar platforms. TOS, as per the "Tape" in the name, required a tape drive. It shared most of the code base and some manuals with IBM's DOS/360. TOS went through 14 releases, and was discontinued when disks such as the IBM 2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM Advanced Peer-to-Peer Networking
IBM Advanced Peer-to-Peer Networking (APPN) is an extension to the Systems Network Architecture (SNA) "that allows large and small computers to communicate as peers across local and wide-area networks." Goals and features The goals of APPN were: * Provide effective routing for SNA traffic * Allow sessions to be established without the involvement of a central computer * Reduce the requirements to predict resource use * Provide prioritization within SNA traffic * Support both legacy and APPN traffic To meet these goals it includes features such as these: * distributed network control * dynamic exchange of network topology information to foster ease of connection, reconfiguration, and route selection * dynamic definition of network resources * automated resource registration and directory lookup. History APPN was defined around 1986, and was meant to complement IBM's Systems Network Architecture. It was designed as a simplification, but it turned out to be significantly complex, in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basic Telecommunications Access Method
Basic Telecommunications Access Method (BTAM) is a low-level programming interface specified by IBM for use on the IBM System/360 for start-stop and binary synchronous telecommunications terminals. Later, IBM specified higher-level interfaces QTAM and TCAM. BTAM was superseded by VTAM for Systems Network Architecture (SNA) devices. BTAM continued to be supported in later iterations of the system architecture, and IBM finally withdrew support in 2000. BTAM requires the application program or transaction processing system to handle almost every detail of the protocol. This is harder than using a higher-layer protocol, but it permits interfacing to non-standard devices in non-standard ways. An access method for terminals BTAM is an access method for interactively communicating with remote terminals, usually connected through a front end processor such as a 270x communications controller, although support for local channel-attached 3270 terminals is included. BTAM dynamically bui ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OS/390
OS/390 is an IBM operating system for the System/390 IBM mainframe computers. Overview OS/390 was introduced in late 1995 in an effort to simplify the packaging and ordering for the key, entitled elements needed to complete a fully functional Multiple Virtual Storage (MVS) operating system package. These elements included, but were not limited to: *Data Facility Storage Management Subsystem Data Facility Product (DFP)Provides access methods to enable I/O to, e.g., Direct access storage device subsystems, printers, tape; provides utilities and program management * Job Entry Subsystem (JES)Provides the ability to submit batch work and manage print * IBM Communications ServerProvides Virtual Telecommunications Access Method (VTAM) and TCP/IP communications protocols An additional benefit of the OS/390 packaging concept was to improve reliability, availability and serviceability (RAS) for the operating system, as the number of different combinations of elements that a custome ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM 3746
The IBM 3745 is the latest and last of a 37xx family of communications controllers for the IBM mainframe environment. As of mid-2009 there were an estimated 7,000+ of the larger 3745 models still in active production status, down from 20,000 or more in 2007. The 3745 and associated 3746 models were once heavily used within financial, insurance and retail industries as well as within government agencies globally. However, today most organizations have migrated away from the use of 3745s. IBM's Enterprise Extender and the Communication Controller for Linux on System z (CCL) have largely displaced the older 3745s. IBM announced in September 2002 that it would no longer manufacture new 3745s, but IBM continues to support the hardware by providing worldwide maintenance service, by providing microcode releases and by supporting the associated software including NCP (Network Control Program) and the virtual telecommunications access method (VTAM). IBM has announced end-of-service ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM Network Control Program
The IBM Network Control Program, or NCP, was software that ran on a IBM 37xx, 37xx communications controller and managed communication with remote devices. NCP provided services comparable to the data link layer and Network Layer functions in the OSI model of a Wide area network. Overview The original IBM Network Control Program ran on the IBM 3705, 3705-I and supported access to older devices by application programs using Telecommunications Access Method, Telecommunications Access Method (TCAM). With the advent of Systems Network Architecture (SNA), NCP was enhanced to connect cluster controllers (such as the IBM 3270#Controllers, IBM 3270) to application programs using TCAM and later to application programs using Virtual Telecommunications Access Method, Virtual Telecommunications Access Method (VTAM). Subsequent versions of NCP were released to run on the IBM 3704, IBM 3705, IBM 3705-II, IBM 3725. IBM 3720, or IBM 3745 Communications Controllers, all of which SNA defined as a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM 3745
The IBM 3745 is the latest and last of a 37xx family of communications controllers for the IBM mainframe environment. As of mid-2009 there were an estimated 7,000+ of the larger 3745 models still in active production status, down from 20,000 or more in 2007. The 3745 and associated 3746 models were once heavily used within financial, insurance and retail industries as well as within government agencies globally. However, today most organizations have migrated away from the use of 3745s. IBM's Enterprise Extender and the Communication Controller for Linux on System z (CCL) have largely displaced the older 3745s. IBM announced in September 2002 that it would no longer manufacture new 3745s, but IBM continues to support the hardware by providing worldwide maintenance service, by providing microcode releases and by supporting the associated software including NCP (Network Control Program) and the virtual telecommunications access method (VTAM). IBM has announced end-of-service ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Access Method
An access method is a function of a mainframe computer, mainframe operating system that enables access to data on disk, tape or other external devices. Access methods were present in several mainframe operating systems since the late 1950s, under a variety of names; the name ''access method'' was introduced in 1963 in the IBM OS/360 operating system.M. A. Auslander, D. C. Larkin, A. L. Scherr: "The Evolution of the MVS Operating System", pages 478-479 Access methods provide an API, application programming interface (API) for programmers to transfer data to or from device, and could be compared to device drivers in non-mainframe operating systems, but typically provide a greater level of functionality. Purpose of access met ...
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Binary Synchronous Communications
Binary Synchronous Communication (BSC or Bisync) is an IBM character-oriented, half-duplex link protocol, announced in 1967 after the introduction of System/360. It replaced the synchronous transmit-receive (STR) protocol used with second generation computers. The intent was that common link management rules could be used with three different character encodings for messages. Six-bit Transcode looked backward to older systems; USASCII with 128 characters and EBCDIC with 256 characters looked forward. Transcode disappeared very quickly but the EBCDIC and USASCII dialects of Bisync continued in use. At one time Bisync was the most widely used communications protocol and is still in limited use in 2013. Framing Bisync differs from protocols that succeeded it in the complexity of message framing. Later protocols use a single framing scheme for all messages sent by the protocol. HDLC, Digital Data Communications Message Protocol (DDCMP), Point-to-Point Protocol (PPP), etc. e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telecommunications Access Method
Telecommunications Access Method (TCAM) is an access method, in IBM's OS/360 and successors computer operating systems on IBM System/360 and later, that provides access to terminals units within a teleprocessing network. Features TCAM provides similar functionality to QTAM, which it replaced. It was the access method for the initial version of Time Sharing Option (TSO). With the advent of IBM's SNA, TCAM was eventually superseded by VTAM. TCAM was said to have the following enhancements over QTAM: * Improved buffering, with more buffering options. * Improved organization of message queuing on disk including multiple volume support. * Back-up copies of messages maintained on disk. * Improved testing and debugging including off-line testing, improved debugging, online terminal testing, and logging. * Improved line handling for inquiry applications. * "Significantly increases speed and efficiency over QTAM." * Improved operator monitoring and control. * Binary Synchronous Suppor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Token Ring
Token Ring is a Physical layer, physical and data link layer computer networking technology used to build local area networks. It was introduced by IBM in 1984, and standardized in 1989 as IEEE Standards Association, IEEE 802.5. It uses a special three-byte frame (networking), frame called a ''token'' that is passed around a logical ''ring'' of workstations or server (computing), servers. This token passing is a channel access method providing fair access for all stations, and eliminating the collision (telecommunications), collisions of contention (telecommunications), contention-based access methods. Following its introduction, Token Ring technology became widely adopted, particularly in corporate environments, but was gradually eclipsed by newer iterations of Ethernet. The last formalized Token Ring standard that was completed was Gigabit Token Ring (IEEE 802.5z), published on May 4, 2001. History A wide range of different local area network technologies were developed in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
