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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] |
ARPANET
The Advanced Research Projects Agency Network (ARPANET) was the first wide-area packet-switched network with distributed control and one of the first computer networks to implement the TCP/IP protocol suite. Both technologies became the technical foundation of the Internet. The ARPANET was established by the Advanced Research Projects Agency (now DARPA) of the United States Department of Defense. Building on the ideas of J. C. R. Licklider, Robert Taylor (computer scientist), Bob Taylor initiated the ARPANET project in 1966 to enable resource sharing between remote computers. Taylor appointed Lawrence Roberts (scientist), Larry Roberts as program manager. Roberts made the key decisions about the request for proposal to build the network. He incorporated Donald Davies' concepts and designs for packet switching, and sought input from Paul Baran on dynamic routing. In 1969, ARPA awarded the contract to build the Interface Message Processors (IMPs) for the network to Bolt Berane ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM 3270
The IBM 3270 is a family of Block-oriented terminal, block oriented display and printer computer terminals introduced by IBM in 1971 and normally used to communicate with IBM mainframes. The 3270 was the successor to the IBM 2260 display terminal. Due to the text color on the original models, these terminals are informally known as ''Monochrome monitor, green screen'' terminals. Unlike a character-oriented terminal, the 3270 minimizes the number of input/output, I/O interrupts required by transferring large blocks of data known as data streams, and uses a high speed proprietary communications interface, using coaxial cable. IBM no longer manufactures 3270 terminals, but the IBM 3270 protocol is still commonly used via TN3270 clients, 3270 emulator, 3270 terminal emulation or web interfaces to access mainframe-based applications, which are sometimes referred to as ''green screen applications''. Principles The 3270 series was designed to connect with mainframe computers, often ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
I/O Channel
In computing, channel I/O is a high-performance input/output (I/O) architecture that is implemented in various forms on a number of computer architectures, especially on mainframe computers. In the past, channels were generally implemented with custom devices, variously named channel, I/O processor, I/O controller, I/O synchronizer, or '' DMA controller''. Overview Many I/O tasks can be complex and require logic to be applied to the data to convert formats and other similar duties. In these situations, the simplest solution is to ask the CPU to handle the logic, but because I/O devices are relatively slow, a CPU could waste time waiting for the data from the device. This situation is called 'I/O bound'. Channel architecture avoids this problem by processing some or all of the I/O task without the aid of the CPU by offloading the work to dedicated logic. Channels are logically self-contained, with sufficient logic and working storage to handle I/O tasks. Some are powerful or flex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
System/370
The IBM System/370 (S/370) is a range of IBM mainframe computers announced as the successors to the IBM System/360, System/360 family on June 30, 1970. The series mostly maintains backward compatibility with the S/360, allowing an easy migration path for customers; this, plus improved performance, were the dominant themes of the product announcement. Early 370 systems differed from the 360 largely in their internal circuitry, moving from the Solid Logic Technology hybrid integrated circuits containing separate transistors to more modern monolithic integrated circuits containing multiple transistors per integrated circuit, which IBM referred to as Monolithic System Technology, or MST. The higher density packaging allowed several formerly optional features from the 360 line to be included as standard features of the machines, floating-point support for instance. The 370 also added a small number of new instructions. At the time of its introduction, the development of virtual mem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Communications Controller For Linux
Communications Controller for Linux (Communications Controller for Linux on System z or CCL) is an IBM software product announced in 2005 that runs under Linux on IBM Z and emulates an IBM 37xx communications controller. CCL runs unmodified IBM Network Control Program (NCP) to allow consolidation of an SNA network infrastructure to IP. According to IBM "SNA traffic enters and leaves CCL as SNA network flows over an OSA adapter. However, your wide area network infrastructure does not need to be SNA. You can consolidate your SNA traffic and use tunneling such as data link switching (DLSw) to encapsulate the SNA communication over an IP network." CCL supports Ethernet and Token Ring local area network (LAN) connectivity directly, and other connectivity through a DLSw router. X.25 X.25 is an ITU-T standard protocol suite for Packet switched network, packet-switched data communication in wide area network, wide area networks (WAN). It was originally defined by the CCITT, Internatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synchronous Data Link Control
Synchronous Data Link Control (SDLC) is a computer serial communication, serial communications protocol first introduced by IBM as part of its Systems Network Architecture (SNA). SDLC is used as layer 2, the data link layer, in the SNA protocol stack. It supports multipoint links as well as error correction. It also runs under the assumption that an SNA header is present after the SDLC header. SDLC was mainly used by IBM mainframe and midrange systems; however, implementations exist on many platforms from many vendors. In the United States and Canada, SDLC can be found in traffic control cabinets. SDLC was released in 1975,PC Lube and Tune accessed 15. October 2009. based on work done for IBM in the early 1970s.. SDLC operates independently on each communications link in the network and can operate on point-to-poi ... [...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] |
Virtual Telecommunications Access Method
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] |
IBM 37xx
IBM 37xx (or 37x5) is a family of IBM Systems Network Architecture (SNA) programmable communications controllers used mainly in mainframe environments. All members of the family ran one of three IBM-supplied programs. *''Emulation Program'' (EP) mimicked the operation of the older IBM 270x non-programmable controllers. *'' Network Control Program'' (NCP) supported Systems Network Architecture devices. *''Partitioned Emulation Program'' (PEP) combined the functions of the two. Models 370x series * 3705 — the oldest of the family, introduced in 1972 to replace the non-programmable IBM 270x family. The 3705 could control up to 352 communications lines. * 3704 was a smaller version, introduced in 1973. It supported up to 32 lines. 371x The 3710 communications controller was introduced in 1984. 372x series The 3725 and the 3720 systems were announced in 1983. The 3725 replaced the hardware line scanners used on previous 370x machines with multiple microcoded processo ... [...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] |
IBM 3705
The IBM 3705 Communications Controller is a simple computer which attaches to an IBM System/360 or System/370. Its purpose is to connect communication lines to the Channel I/O, mainframe channel. It was a first front end processor, communications controller of the popular IBM 37xx series. It was announced in March 1972. Designed for semiconductor memory which was not ready at the time of announcement, the 3705-I had to use 1.2 microsecond core storage; the later 3705-II uses 1.0 microsecond SRAM. Solid Logic Technology components, similar to those in S/370, were used. The 3705 normally occupies a single frame two feet wide and three feet deep. Up to three expansion frames can be attached for a theoretical capacity of 352 half-duplex lines and two independent channel adapters. The 3704 is an entry-level version of the 3705 with limited features. Purpose IBM intended it to be used in three ways: # Emulation of the older IBM 2703, IBM 2703 Communications Controller and its predecess ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
