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Channel-to-channel Adapter
In IBM mainframe technology, a channel-to-channel adapter (CTCA) is a device that connects two input/output channels on (usually) two separate computer systems. The adapter allows one computer system to be treated as an input/output device by another. It is used "to link the processing units in a loosely coupled multiprocessing system. Virtual channel-to-channel adapters (VCTCA) are often used to communicate between two virtual machines in the z/VM operating system. The Virtual Machine Communication Facility (VMCF), and later Inter User Communication Vehicle Inter User Communication Vehicle (IUCV) is a data transfer mechanism in IBM VM line of operating systems. It was introduced with VM/SP Release 1 in 1980. It allows establishment of point to point communication channels, either between two virtual ... (IUCV) are now often used in place of VCTCAs because they provide a simpler interface and improved performance. References IBM mainframe technology {{comp-hardware- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM Mainframe
IBM mainframes are large computer systems produced by IBM since 1952. During the 1960s and 1970s, IBM dominated the large computer market. Current mainframe computers in IBM's line of business computers are developments of the basic design of the IBM System/360. First and second generation From 1952 into the late 1960s, IBM manufactured and marketed several large computer models, known as the IBM 700/7000 series. The first-generation 700s were based on vacuum tubes, while the later, second-generation 7000s used transistors. These machines established IBM's dominance in electronic data processing ("EDP"). IBM had two model categories: one (701, 704, 709, 7030, 7090, 7094, 7040, 7044) for engineering and scientific use, and one (702, 705, 705-II, 705-III, 7080, 7070, 7072, 7074, 7010) for commercial or data processing use. The two categories, scientific and commercial, generally used common peripherals but had completely different instruction sets, and there were incompatibiliti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Input/output
In computing, input/output (I/O, or informally io or IO) is the communication between an information processing system, such as a computer, and the outside world, possibly a human or another information processing system. Inputs are the signals or data received by the system and outputs are the signals or data sent from it. The term can also be used as part of an action; to "perform I/O" is to perform an input or output operation. are the pieces of hardware used by a human (or other system) to communicate with a computer. For instance, a keyboard or computer mouse is an input device for a computer, while monitors and printers are output devices. Devices for communication between computers, such as modems and network cards, typically perform both input and output operations. Any interaction with the system by a interactor is an input and the reaction the system responds is called the output. The designation of a device as either input or output depends on perspective. Mice a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Channel I/O
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 (in computer perspective) 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. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiprocessing
Multiprocessing is the use of two or more central processing units (CPUs) within a single computer system. The term also refers to the ability of a system to support more than one processor or the ability to allocate tasks between them. There are many variations on this basic theme, and the definition of multiprocessing can vary with context, mostly as a function of how CPUs are defined ( multiple cores on one die, multiple dies in one package, multiple packages in one system unit, etc.). According to some on-line dictionaries, a multiprocessor is a computer system having two or more processing units (multiple processors) each sharing main memory and peripherals, in order to simultaneously process programs. A 2009 textbook defined multiprocessor system similarly, but noting that the processors may share "some or all of the system’s memory and I/O facilities"; it also gave tightly coupled system as a synonymous term. At the operating system level, ''multiprocessing'' is som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virtual Machine
In computing, a virtual machine (VM) is the virtualization/emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized hardware, software, or a combination. Virtual machines differ and are organized by their function, shown here: * '' System virtual machines'' (also termed full virtualization VMs) provide a substitute for a real machine. They provide functionality needed to execute entire operating systems. A hypervisor uses native execution to share and manage hardware, allowing for multiple environments which are isolated from one another, yet exist on the same physical machine. Modern hypervisors use hardware-assisted virtualization, virtualization-specific hardware, primarily from the host CPUs. * Process virtual machines are designed to execute computer programs in a platform-independent environment. Some virtual machine emulators, such as QEMU and video ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Z/VM
z/VM is the current version in IBM's VM family of virtual machine operating systems. z/VM was first released in October 2000 and remains in active use and development . It is directly based on technology and concepts dating back to the 1960s, with IBM's CP/CMS on the IBM System/360-67 (see article History of CP/CMS for historical details). z/VM runs on IBM's IBM Z family of computers. It can be used to support large numbers (thousands) of Linux virtual machines. (See Linux on IBM Z.) On September 16, 2022, IBM released z/VM Version 7.3 which requires z/Architecture, implemented in IBM's EC12, BC12 and later models. See also * z/OS * OpenSolaris for System z * z/TPF * z/VSE * PR/SM * Time-sharing system evolution This article covers the evolution of time-sharing systems, providing links to major early time-sharing operating systems, showing their subsequent evolution. Time-sharing Time-sharing was first proposed in the mid- to late-1950s and first impleme ... References ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virtual Machine Communication Facility
The IBM Virtual Machine Communication Facility (VMCF) is a feature of the VM/370 operating system introduced in Release 3 in 1976. It "provides a method of communication and data transfer between virtual machines operating under the same VM/370 system." VMCF uses paravirtualization through the ''diagnose'' instruction VMCF SEND function to send data, in blocks of up to 2048 bytes, from one virtual machine to another. The receiving virtual machine accesses the data thru the diagnose RECEIVE function. It provides a simpler interface and greater performance than the prior use of virtual channel-to-channel adapters for the same purpose. References See also * Inter User Communication Vehicle Inter User Communication Vehicle (IUCV) is a data transfer mechanism in IBM VM line of operating systems. It was introduced with VM/SP Release 1 in 1980. It allows establishment of point to point communication channels, either between two virtual ... IBM mainframe operating systems VM (opera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inter User Communication Vehicle
Inter User Communication Vehicle (IUCV) is a data transfer mechanism in IBM VM line of operating systems. It was introduced with VM/SP Release 1 in 1980. It allows establishment of point to point communication channels, either between two virtual machines or between a virtual machine and hypervisor services. In effect, IUCV provides a form of message-based interaction between virtual machines that anticipated the client/server interaction between network connected physical machines that emerged later on distributed systems. IUCV is implemented by CP (the VM hypervisor) and controls all aspects of session establishments, message passing and flow control. IUCV basics Initializing IUCV Before a virtual machine can use the IUCV service, it must first indicate the address of an area within its address space where CP will be able to store information regarding pending information or status. Therefore, the DECLARE BUFFER method must be invoked first. The IUCV Path In IUCV terminology, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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