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Task Control Block
The Task Control Block (TCB) contains the state of a task in, e.g., OS/360 and successors on IBM System/360 architecture and successors. The TCB in OS/360 and successors In OS/360, OS/VS1, SVS, MVS/370, MVS/XA, MVS/ESA, OS/390 and z/OS, the TCB contains, among other data, non-dispatchability flags and the general and floating point registers for a task that is not currently assigned to a CPU. A TCB provides an anchor for a linked list of other, related request blocks (RBs); the top-linked RB for a TCB contains the Program status word (PSW) when the task is not assigned to a CPU. When the control program's dispatcher selects a TCB to be dispatched, the dispatcher loads registers from the TCB and loads the PSW from the top RB of the TCB, thereby dispatching the unit of work. Request Blocks OS/360 has the following types of request blockss ; Interruption Request Block : An IRB is used to handle an asynchronous exit. ; Program Request Block : A PRB represents a module invoked wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thread (computing)
In computer science, a thread of execution is the smallest sequence of programmed instructions that can be managed independently by a scheduler, which is typically a part of the operating system. The implementation of threads and processes differs between operating systems. In Modern Operating Systems, Tanenbaum shows that many distinct models of process organization are possible.TANENBAUM, Andrew S. Modern Operating Systems. 1992. Prentice-Hall International Editions, ISBN 0-13-595752-4. In many cases, a thread is a component of a process. The multiple threads of a given process may be executed concurrently (via multithreading capabilities), sharing resources such as memory, while different processes do not share these resources. In particular, the threads of a process share its executable code and the values of its dynamically allocated variables and non- thread-local global variables at any given time. History Threads made an early appearance under the name of "tasks ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UNIX
Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and others. Initially intended for use inside the Bell System, AT&T licensed Unix to outside parties in the late 1970s, leading to a variety of both academic and commercial Unix variants from vendors including University of California, Berkeley (Berkeley Software Distribution, BSD), Microsoft (Xenix), Sun Microsystems (SunOS/Solaris (operating system), Solaris), Hewlett-Packard, HP/Hewlett Packard Enterprise, HPE (HP-UX), and IBM (IBM AIX, AIX). In the early 1990s, AT&T sold its rights in Unix to Novell, which then sold the UNIX trademark to The Open Group, an industry consortium founded in 1996. The Open Group allows the use of the mark for certified operating systems that comply with the Single UNIX Specification (SUS). Unix systems are chara ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OS/360 And Successors
OS/360, officially known as IBM System/360 Operating System, is a discontinued batch processing operating system developed by IBM for their then-new System/360 mainframe computer, announced in 1964; it was influenced by the earlier IBSYS/IBJOB and Input/Output Control System (IOCS) packages for the IBM 7090/7094 and even more so by the PR155 Operating System for the IBM 1410/ 7010 processors. It was one of the earliestJust a few years after Atlas Supervisor, Burroughs MCP and GECOS operating systems to require the computer hardware to include at least one direct access storage device. Although OS/360 itself was discontinued, successor operating systems, including the virtual storage MVS and the 64-bit z/OS, are still run and maintain application-level compatibility with OS/360. Overview IBM announced three different levels of OS/360, generated from the same tapes and sharing most of their code. IBM eventually renamed these options and made some significant design changes: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM System/360 Architecture
The IBM System/360 architecture is the model independent architecture for the entire S/360 line of mainframe computers, including but not limited to the instruction set architecture. The elements of the architecture are documented in the ''IBM System/360 Principles of Operation'' and the ''IBM System/360 I/O Interface Channel to Control Unit Original Equipment Manufacturers' Information'' manuals. Features The System/360 architecture provides the following features: * 16 32-bit general-purpose registers * 4 64-bit floating-point registers * 64-bit processor status register (PSW), which includes a 24-bit instruction address * 24-bit (16 MB) byte-addressable memory space * Big-endian byte/word order * A ''standard instruction set'', including fixed-point binary arithmetic and logical instructions, present on all System/360 models (except the Model 20, see below). ** A ''commercial instruction set'', adding decimal arithmetic instructions, is optional on some models, as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OS/360
OS/360, officially known as IBM System/360 Operating System, is a discontinued batch processing operating system developed by IBM for their then-new System/360 mainframe computer, announced in 1964; it was influenced by the earlier IBSYS/IBJOB and Input/Output Control System (IOCS) packages for the IBM 7090/7094 and even more so by the PR155 Operating System for the IBM 1410/ 7010 processors. It was one of the earliestJust a few years after Atlas Supervisor, Burroughs MCP and GECOS operating systems to require the computer hardware to include at least one direct access storage device. Although OS/360 itself was discontinued, successor operating systems, including the virtual storage MVS and the 64-bit z/OS, are still run and maintain application-level compatibility with OS/360. Overview IBM announced three different levels of OS/360, generated from the same tapes and sharing most of their code. IBM eventually renamed these options and made some significant design changes: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OS/VS1
Operating System/Virtual Storage 1, or OS/VS1, is a discontinued IBM mainframe computer operating system designed to be run on IBM System/370 hardware. It was the successor to the OS/360 and successors#MFT, Multiprogramming with a Fixed number of Tasks (MFT) option of System/360's operating system OS/360 and successors, OS/360. OS/VS1, in comparison to its predecessor, supported virtual memory (then called ''virtual storage''). OS/VS1 was generally available during the 1970s and 1980s, and it is no longer supported by IBM. Description OS/VS1 was OS/360 MFT II with a single virtual address space; by comparison, OS/VS2 (SVS), OS/VS2 SVS was OS/360 and successors#MVT, OS/360 MVT with a single virtual address space. OS/VS1 was often installed on mid-range IBM mainframe systems, such as the System/370 Model 145 and, later, the System/370 Model 148. OS/VS1 was intended to manage a medium-sized work load (for the 1970s) consisting only of batch processing applications, running within a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OS/VS2 (SVS)
Single Virtual Storage (SVS) refers to Release 1 of Operating System/Virtual Storage 2 (OS/VS2); it is the successor system to the MVT option of Operating System/360. OS/VS2 (SVS) was a stopgap measure pending the availability of MVS, although IBM provided support and enhancements to SVS long after shipping MVS. SVS provides a ''single'' 16MiB address space which is shared by all tasks in the system, regardless of the size of physical memory. Differences from MVT OS/360 used the Interval Timer feature for providing time of day and for triggering time-dependent events. The support for S/370 made limited use of new timing facilities, but retained a dependency on the Interval Timer. SVS uses the TOD Clock, Clock Comparator and CPU Timer exclusively. OS/360 loads error recovery and transient SVC routines from SYS1.SVCLIB into small transient areas. SVS loads these routine from SYS1.LPALIB into the Pageable Link Pack Area (PLPA) during an IPL with the Create LPA (CLPA) option; the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MVS/370
Multiple Virtual Storage, more commonly called MVS, was the most commonly used operating system on the System/370 and System/390 IBM mainframe computers. IBM developed MVS, along with OS/VS1 and SVS, as a successor to OS/360. It is unrelated to IBM's other mainframe operating system lines, e.g., VSE, VM, TPF. Overview First released in 1974, MVS was extended by program products with new names multiple times: * first to MVS/SE (MVS/System Extensions),some print media used the singular, MVS/System Extension: Computerworld, 15 Dec 1980 - Page 5; 26 June 1978 - Page 8 * next to MVS/SP (MVS/System Product) Version 1, * next to MVS/XA (MVS/eXtended Architecture), * next to MVS/ESA (MVS/Enterprise Systems Architecture), * then to OS/390 and * finally to z/OS (when 64-bit support was added with the zSeries models). IBM added UNIX support (originally called OpenEdition MVS) in MVS/SP V4.3 and has obtained POSIX and UNIX™ certifications at several different levels from IEEE, X ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MVS/XA
Multiple Virtual Storage, more commonly called MVS, was the most commonly used operating system on the System/370 and System/390 IBM mainframe computers. IBM developed MVS, along with OS/VS1 and SVS, as a successor to OS/360. It is unrelated to IBM's other mainframe operating system lines, e.g., VSE, VM, TPF. Overview First released in 1974, MVS was extended by program products with new names multiple times: * first to MVS/SE (MVS/System Extensions),some print media used the singular, MVS/System Extension: Computerworld, 15 Dec 1980 - Page 5; 26 June 1978 - Page 8 * next to MVS/SP (MVS/System Product) Version 1, * next to MVS/XA (MVS/eXtended Architecture), * next to MVS/ESA (MVS/Enterprise Systems Architecture), * then to OS/390 and * finally to z/OS (when 64-bit support was added with the zSeries models). IBM added UNIX support (originally called OpenEdition MVS) in MVS/SP V4.3 and has obtained POSIX and UNIX™ certifications at several different levels from IEEE, X ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MVS/ESA
Multiple Virtual Storage, more commonly called MVS, was the most commonly used operating system on the System/370 and System/390 IBM mainframe computers. IBM developed MVS, along with OS/VS1 and SVS, as a successor to OS/360. It is unrelated to IBM's other mainframe operating system lines, e.g., VSE, VM, TPF. Overview First released in 1974, MVS was extended by program products with new names multiple times: * first to MVS/SE (MVS/System Extensions),some print media used the singular, MVS/System Extension: Computerworld, 15 Dec 1980 - Page 5; 26 June 1978 - Page 8 * next to MVS/SP (MVS/System Product) Version 1, * next to MVS/XA (MVS/eXtended Architecture), * next to MVS/ESA (MVS/Enterprise Systems Architecture), * then to OS/390 and * finally to z/OS (when 64-bit support was added with the zSeries models). IBM added UNIX support (originally called OpenEdition MVS) in MVS/SP V4.3 and has obtained POSIX and UNIX™ certifications at several different levels from IEEE, ... [...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 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., DASD 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 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 customer could order and run was drastically reduced. This reduced the overall time required for custome ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Z/OS
z/OS is a 64-bit operating system for IBM z/Architecture mainframes, introduced by IBM in October 2000. It derives from and is the successor to OS/390, which in turn was preceded by a string of MVS versions.Starting with the earliest: * OS/VS2 Release 2 through Release 3.8 * MVS/System Extensions (MVS/SE) * MVS/System Product (MVS/SP) Version 1 * MVS/System Product Version 2 (MVS/Extended Architecture, MVS/XA) * MVS/System Product Version 3 (MVS/Enterprise Systems Architecture, MVS/ESA) * MVS/ESA SP Version 4 * MVS/ESA SP Version 5 Like OS/390, z/OS combines a number of formerly separate, related products, some of which are still optional. z/OS has the attributes of modern operating systems, but also retains much of the older functionality originated in the 1960s and still in regular use—z/OS is designed for backward compatibility. Major characteristics z/OS supportsSome, e.g., TSO/E, are bundled with z/OS, others, e.g.,CICS, are separately priced. stable mainframe fac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
