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IUCV
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] |
VM (operating System)
VM (often: VM/CMS) is a family of IBM virtual machine operating systems used on IBM mainframes System/370, System/390, zSeries, System z and compatible systems, including the Hercules emulator for personal computers. The following versions are known: ;Virtual Machine Facility/370 :VM/370, released in 1972, is a System/370 reimplementation of earlier CP/CMS operating system. ;VM/370 Basic System Extensions Program Product :VM/BSE (BSEPP) is an enhancement to VM/370 that adds support for more devices (such as 3370-type fixed-block-architecture DASD drives), improvements to the CMS environment (such as an improved editor), and some stability enhancements to CP. ;VM/370 System Extensions Program Product :VM/SE (SEPP) is an enhancement to VM/370 that includes the facilities of VM/BSE, as well as a few additional fixes and features. ;Virtual Machine/System Product :VM/SP, a milestone version, replaces VM/370, VM/BSE and VM/SE. Release 1 added EXEC2 and XEDIT System Product Edit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Group Control System(VM)
Group Control System (GCS) is an operating system made by IBM, meant to run as a guest of VM. GCS is an integral component of the discontinued VM/SP (since VM/SP 4), VM/XA SP, VM/ESA and current z/VM IBM System product offerings. Overview GCS's purpose is to provide an environment to run some specific OS/MVS-based applications and networking middleware under VM. To this end, GCS provides a limited simulation of the OS/MVS APIs. While CMS, the usual VM guest, already has OS simulation, it is not extensive enough to run some applications such as VTAM. Specifically, GCS provides OS multitasking support. In order to be able to spread the load over several virtual machines, GCS also implements a notion of group where each group member virtual machine can interact with one another. To implement this, GCS uses several techniques: * A writable shared segment * IUCV communications between virtual machines * A recovery virtual machine, designed to clean up locks in the shared segment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Quiesce
To quiesce is to pause or alter a device or application to achieve a consistent state, usually in preparation for a backup or other maintenance. Description In software applications that modify information stored on disk, this generally involves flushing any outstanding writes; see buffering. With telecom applications, this generally involves allowing existing callers to finish their call but preventing new calls from initiating. Example Perhaps the best known support for this was incorporated into Microsoft Shadow Copies which was introduced in Microsoft Windows Server 2003. For an application to be quiesced during the shadow copy process, it must register itself as a writer and it is responsible for putting itself into a quiescent mode upon notification. Vendor schemes Various database and application vendors implement schemes to provide support for this feature including: * Symantec's Livestate – now includes a quiesce process, as does VMware's VI3 snapshot and VCB featu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RSCS
Remote Spooling Communications Subsystem or RSCS is a subsystem ("virtual machine" in VM terminology) of IBM's VM/370 operating system which accepts files transmitted to it from local or remote system and users and transmits them to destination local or remote users and systems. RSCS also transmits commands and messages among users and systems. RSCS is the software that powered the world’s largest network (or network of networks) prior to the Internet and directly influenced both internet development and user acceptance of networking between independently managed organizations. RSCS was developed by Edson Hendricks and T.C. Hartmann. Both as an IBM product and as an IBM internal network, it later became known as VNET. The network interfaces continued to be called the RSCS compatible protocols and were used to interconnect with IBM systems other than VM systems (typically MVS) and non-IBM computers. The history of this program, and its influence on IBM and the IBM user comm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TCP/IP
The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the set of communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suite are the Transmission Control Protocol (TCP), the User Datagram Protocol (UDP), and the Internet Protocol (IP). In the development of this networking model, early versions of it were known as the Department of Defense (DoD) model because the research and development were funded by the United States Department of Defense through DARPA. The Internet protocol suite provides end-to-end data communication specifying how data should be packetized, addressed, transmitted, routed, and received. This functionality is organized into four abstraction layers, which classify all related protocols according to each protocol's scope of networking. An implementation of the layers for a particular application forms a protocol stack. From lowest to high ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S/390
The IBM System/390 is a discontinued mainframe product family implementing the ESA/390, the fifth generation of the System/360 instruction set architecture. The first computers to use the ESA/390 were the Enterprise System/9000 (ES/9000) family, which were introduced in 1990. These were followed by the 9672, Multiprise, and Integrated Server families of System/390 in 1994–1999, using CMOS microprocessors. The ESA/390 succeeded the ESA/370 used in the Enhanced 3090 and 4381 "E" models, and the System/370 architecture last used in the IBM 9370 low-end mainframe. The ESA/390 was succeeded by the 64-bit z/Architecture in 2000. History On February 15, 1988, IBM announced Enterprise Systems Architecture/370 (ESA/370) for 3090 enhanced ("E") models and for 4381 model groups 91E and 92E. In additional to the primary and secondary addressing modes that System/370 Extended Architecture (S/370-XA) supports, ESA has an access register mode in which each use of general regi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Z/Architecture
z/Architecture, initially and briefly called ESA Modal Extensions (ESAME), is IBM's 64-bit complex instruction set computer (CISC) instruction set architecture, implemented by its mainframe computers. IBM introduced its first z/Architecture-based system, the z900, in late 2000. Later z/Architecture systems include the IBM z800, z990, z890, System z9, System z10, zEnterprise 196, zEnterprise 114, zEC12, zBC12, z13, z14, z15 and z16. z/Architecture retains backward compatibility with previous 32-bit-data/31-bit-addressing architecture ESA/390 and its predecessors all the way back to the 32-bit-data/24-bit-addressing System/360. The IBM z13 is the last z Systems server to support running an operating system in ESA/390 architecture mode. However, all 24-bit and 31-bit problem-state application programs originally written to run on the ESA/390 architecture will be unaffected by this change. Each z/OS address space, called a 64-bit address space, is 16 exabytes in size. C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linux
Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which includes the kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name "GNU/Linux" to emphasize the importance of GNU software, causing some controversy. Popular Linux distributions include Debian, Fedora Linux, and Ubuntu, the latter of which itself consists of many different distributions and modifications, including Lubuntu and Xubuntu. Commercial distributions include Red Hat Enterprise Linux and SUSE Linux Enterprise. Desktop Linux distributions include a windowing system such as X11 or Wayland, and a desktop environment such as GNOME or KDE Plasma. Distributions intended for ser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VMCF
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] |
Virtualization Software
In computing, virtualization or virtualisation (sometimes abbreviated v12n, a numeronym) is the act of creating a virtual (rather than actual) version of something at the same abstraction level, including virtual computer hardware platforms, storage devices, and computer network resources. Virtualization began in the 1960s, as a method of logically dividing the system resources provided by mainframe computers between different applications. An early and successful example is IBM CP/CMS. The control program CP provided each user with a simulated stand-alone System/360 computer. Since then, the meaning of the term has broadened. Hardware virtualization ''Hardware virtualization'' or ''platform virtualization'' refers to the creation of a virtual machine that acts like a real computer with an operating system. Software executed on these virtual machines is separated from the underlying hardware resources. For example, a computer that is running Arch Linux may host a virtual machi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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