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Sysplex
In computing, a Parallel Sysplex is a cluster of IBM mainframes acting together as a single system image with z/OS. Used for disaster recovery, Parallel Sysplex combines data sharing and parallel computing to allow a cluster of up to 32 systems to share a workload for high performance and high availability. Sysplex In 1990, IBM mainframe computers introduced the concept of a Systems Complex, commonly called a Sysplex, with MVS/ESA SPV4.1. This allows authorized components in up to eight logical partitions (LPARs) to communicate and cooperate with each other using the XCF protocol. Components of a Sysplex include: * A common time source to synchronize all member systems' clocks. This can involve either a Sysplex timer (Model 9037), or the Server Time Protocol (STP) * Global Resource Serialization (GRS), which allows multiple systems to access the same resources concurrently, serializing where necessary to ensure exclusive access * Cross System Coupling Facility ( XCF), which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM XCF
In IBM mainframes, a Cross-system Coupling Facility, or XCF, is a component of z/OS that manages communications between applications in a sysplex. Applications may be on the same system or different systems. Systems communicate using messages transported by one of two mechanisms: *Dedicated channel-to-channel links (CTC links). *Structures in a Coupling Facility In IBM System/390 and IBM Z mainframe computers, a Coupling Facility or CF is a piece of computer hardware or virtual machine that coordinates multiple processors. A Parallel Sysplex relies on one or more Coupling Facilities (CFs). A coupling ..., only available in Parallel Sysplex, not in base sysplex. In a parallel sysplex decisions about which of these two transport mechanisms to use for routing a specific message are made dynamically. Within a single z/OS system messages are transported using cross-memory services, rather than being routed through either of the physical transport mechanisms. Applications joi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Workload Manager
In IBM mainframes, Workload Manager (WLM) is a base component of MVS/ESA mainframe operating system, and its successors up to and including z/OS. It controls the access to system resources for the work executing on z/OS based on administrator-defined goals. Workload Manager components also exist for other operating systems. For example, an IBM Workload Manager is also a software product for AIX operating system. Workload Manager On a mainframe computer many differents applications execute at the same time. The expectations for executing work are consistent execution times and predictable access to databases. On z/OS the Workload Manager (WLM) component fulfills these needs by controlling work's access to system resources based on external specifications by the system administrator... The system administrator classifies work to service classes. The classification mechanism uses work attributes like transaction names, user identifications or program names which specific applic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
System Z9
IBM System z9 is a line of IBM mainframe computers. The first models were available on September 16, 2005. The System z9 also marks the end of the previously used eServer zSeries naming convention. It was also the last mainframe computer that NASA ever used. Background System z9 is a mainframe using the z/Architecture, previously known as ESAME. z/Architecture is a 64-bit architecture which replaces the previous 31-bit-addressing/32-bit-data ESA/390 architecture while remaining completely compatible with it as well as the older 24-bit-addressing/32-bit-data System/360 architecture. The primary advantage of this arrangement is that memory intensive applications like DB2 are no longer bounded by 31-bit memory restrictions while older applications can run without modifications. Name change With the announcement of the System z9 Business Class server, IBM has renamed the System z9 109 as the System z9 Enterprise Class server. IBM documentation abbreviates them as the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Global Resource Serialization
Global Resource Serialization (GRS) is the component within the IBM z/OS operating system responsible for enabling fair access to serially reusable computing resources, such as datasets and tape drives or virtual resources, such as lists, queues, and control blocks. Programs can request exclusive access to a resource (which means that program and all subsequent requesting programs are blocked until that program is given access to the resource), usually requested when a program needs to update the resource or shared access (which means that multiple programs can be given access to the resource), usually requested when a program only needs to query the state of the resource. GRS manages all requests in FIFO (first in/first out) order.IBM Knowledge Center: https://www.ibm.com/docs/en/zos/2.5.0?topic=ieasysxx-grs Scoping GRS manages resources at three different levels of scoping: #STEP - this level is for resources that exist within a single MVS address space. Only threads (tasks) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virtual Storage Access Method
Virtual Storage Access Method (VSAM) is an IBM direct-access storage device (DASD) file storage access method, first used in the OS/VS1, OS/VS2 Release 1 (SVS) and Release 2 (MVS) operating systems, later used throughout the Multiple Virtual Storage (MVS) architecture and now in z/OS. Originally a record-oriented filesystem, VSAM comprises four data set ''organizations'': key-sequenced (KSDS), relative record (RRDS), entry-sequenced (ESDS) and linear (LDS). The KSDS, RRDS and ESDS organizations contain records, while the LDS organization (added later to VSAM) contains a sequence of pages with no intrinsic record structure, for use as a memory-mapped file. Overview An IBM ''Redbook'' named "VSAM PRIMER" (especially when used with the "Virtual Storage Access Method (VSAM) Options for Advanced Applications" manual) explains the concepts needed to make use of VSAM. IBM uses the term ''data set'' in official documentation as a synonym for ''file'', and ''direct-access storage dev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Operating System
An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for efficient use of the system and may also include accounting software for cost allocation of Scheduling (computing), processor time, mass storage, peripherals, and other resources. For hardware functions such as input and output and memory allocation, the operating system acts as an intermediary between programs and the computer hardware, although the application code is usually executed directly by the hardware and frequently makes system calls to an OS function or is interrupted by it. Operating systems are found on many devices that contain a computerfrom cellular phones and video game consoles to web servers and supercomputers. , Android (operating system), Android is the most popular operating system with a 46% market share, followed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middleware
Middleware is a type of computer software program that provides services to software applications beyond those available from the operating system. It can be described as "software glue". Middleware makes it easier for software developers to implement communication and input/output, so they can focus on the specific purpose of their application. It gained popularity in the 1980s as a solution to the problem of how to link newer applications to older legacy systems, although the term had been in use since 1968. In distributed applications The term is most commonly used for software that enables communication and management of data in distributed applications. An IETF workshop in 2000 defined middleware as "those services found above the transport (i.e. over TCP/IP) layer set of services but below the application environment" (i.e. below application-level APIs). In this more specific sense ''middleware'' can be described as the hyphen ("-") in '' client-server'', or the ''-to-'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peer To Peer Remote Copy
Peer to Peer Remote Copy or PPRC is a protocol to storage replication, replicate a storage volume to another control unit at a remote site. Synchronous replication, Synchronous PPRC causes each write to the primary storage volume to be performed to the secondary volume as well, and the I/O is only considered complete when the update to both the primary and secondary volumes has completed. Asynchronous PPRC will flag tracks on the primary to be duplicated to the secondary when time permits. PPRC is also the name IBM calls their implementation of the protocol for their storage hardware. Other vendors have their own implementation. For example, the HDS implementation is called TrueCopy. EMC also provides a similar capability on their VPLEX platforms called "MirrorView". PPRC can be used to provide very fast data recovery due to failure of the primary site. In IBM zSeries computers with two direct access storage device (DASD) control units connected through dedicated connections, PPRC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extended Remote Copy
Extended Remote Copy or XRC is an IBM zSeries and System z9 mainframe computer technology for data replication. It combines supported hardware and z/OS software to provide asynchronous replication over long distances. It is complementary to IBM's Peer to Peer Remote Copy (PPRC) service, which is designed to operate either synchronously or asynchronously over shorter distances. XRC as a z/OS copy services solution can be compared to Global Mirror for ESS, which is a controller-based solution for either the open systems or z/Series environments. Both Global Mirror for ESS (Asynchronous PPRC) and XRC (Global Mirror for z/Series) are asynchronous replication technologies, although their implementations are somewhat different. Extended Remote Copy or XRC is now known as Global Mirror for z/Series (XRC). XRC is a z/Series asynchronous disk mirroring technique which is effective over any distance. It keeps the data time consistent across multiple ESS (Enterprise Storage Server) or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM Global Mirror
Global Mirror is an IBM technology that provides data replication over extended distances between two sites for business continuity and disaster recovery. If adequate bandwidth exists, Global Mirror provides a recovery point objective (RPO) of as low as 3–5 seconds between the two sites at extended distances with no performance impact on the application at the primary site. It replicates the data asynchronously and also forms a consistency group at a regular interval allowing a clean recovery of the application. The two sites can be on separate continents or simply on different utility grids. IBM also provides a synchronous data replication called Metro Mirror, which is designed to support replication at "Metropolitan" distances of (normally) less than 300 km. Global Mirror is based on IBM Copy Services functions: Global Copy and FlashCopy. Global mirror periodically pauses updates of the primary volumes and swaps change recording bitmaps. It then uses the previous b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
