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A disk operating system is a computer operating system that resides on and can use a disk storage device, such as a floppy disk, hard disk drive, or optical disc. A disk operating system must provide a file system for organizing, reading, and writing files on the storage disk. Strictly speaking, this definition does not apply to current generations of operating systems, such as versions of Microsoft Windows in use, and is more appropriately used only for older generations of operating systems.
A direct-access storage device (DASD) is a secondary storage device in which "each physical record has a discrete location and a unique address". IBM coined the term DASD as a shorthand describing hard disk drives, magnetic drums, and data cells. Later, optical disc drives and flash memory units are also classified as DASD. The term DASD contrasts with sequential storage media such as magnetic tape, and unit record equipment such as card devices like card readers and punches.
Computer operating systems (OSes) provide a set of functions needed and used by most application programs on a computer, and the links needed to control and synchronize computer hardware. On the first computers, with no operating system, every program needed the full hardware specification to run correctly and perform standard tasks, and its own drivers for peripheral devices like printers and punched paper card readers. The growing complexity of hardware and application programs eventually made operating systems a necessity for everyday use.
IBM Information Management System (IMS) is a joint hierarchical database and information management system with extensive transaction processing capabilities.
IBM CICS is a family of mixed language application servers that provide online transaction management and connectivity for applications on IBM mainframe systems under z/OS and z/VSE.
In computing, spooling is a specialized form of multi-programming for the purpose of copying data between different devices. In contemporary systems, it is usually used for mediating between a computer application and a slow peripheral, such as a printer. Spooling allows programs to "hand off" work to be done by the peripheral and then proceed to other tasks, or to not begin until input has been transcribed. A dedicated program, the spooler, maintains an orderly sequence of jobs for the peripheral and feeds it data at its own rate. Conversely, for slow input peripherals, such as a card reader, a spooler can maintain a sequence of computational jobs waiting for data, starting each job when all of the relevant input is available; see batch processing. The spool itself refers to the sequence of jobs, or the storage area where they are held. In many cases the spooler is able to drive devices at their full rated speed with minimal impact on other processing.
Disk Operating System/360, also DOS/360, or simply DOS, is a discontinued operating system for IBM mainframes. It was announced by IBM on the last day of 1964, and it was first delivered in June 1966. In its time, DOS/360 was the most widely used operating system in the world.
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.
IBM MQ is a family of message-oriented middleware products that IBM launched in December 1993. It was originally called MQSeries, and was renamed WebSphere MQ in 2002 to join the suite of WebSphere products. In April 2014, it was renamed IBM MQ. The products that are included in the MQ family are IBM MQ, IBM MQ Advanced, IBM MQ Appliance, IBM MQ for z/OS, and IBM MQ on IBM Cloud.
Binary Synchronous Communication is an IBM character-oriented, half-duplex link protocol, announced in 1967 after the introduction of System/360. It replaced the synchronous transmit-receive (STR) protocol used with second generation computers. The intent was that common link management rules could be used with three different character encodings for messages. Six-bit Transcode looked backwards to older systems; USASCII with 128 characters and EBCDIC with 256 characters looked forward. Transcode disappeared very quickly but the EBCDIC and USASCII dialects of Bisync continued in use.
The IBM Network Control Program, or NCP, was software that ran on a 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.
Basic Telecommunications Access Method (BTAM) is a low-level programming interface specified by IBM for use on the IBM System/360 for start-stop and binary synchronous telecommunications terminals. Later, IBM specified higher-level interfaces QTAM and TCAM.
An access method is a function of a mainframe operating system that enables access to data on disk, tape or other external devices. They were introduced in 1963 in IBM OS/360 operating system. Access methods provide an application programming interface (API) for programmers to transfer data to or from device, and could be compared to device drivers in non-mainframe operating systems, but typically provide a greater level of functionality.
In IBM mainframe operating systems, Basic sequential access method (BSAM) is an access method to read and write datasets sequentially. BSAM is available on OS/360, OS/VS2, MVS, z/OS, and related operating systems.
In IBM mainframe operating systems, Execute Channel Program (EXCP) is a supervisor call for low-level device access, where the programmer is responsible for providing a channel program—a list of device-specific commands (CCWs)—to be executed by I/O channels, control units and devices. EXCP for OS/360 and successors is more specifically described in the OS System Programmer's Guide.; EXCP for DOS/360 and successors is more specifically described in DOS Supervisor and I/O Macros. This article mostly reflects OS/360 through [z/OS]; some details are different for TOS/360 and DOS/360 through z/VSE.
The history of operating systems running on IBM mainframes is a notable chapter of history of mainframe operating systems, because of IBM's long-standing position as the world's largest hardware supplier of mainframe computers.
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 heavily influenced by the earlier IBSYS/IBJOB and Input/Output Control System (IOCS) packages. It was one of the earliest operating systems to require the computer hardware to include at least one direct access storage device.
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.
DUCS was a teleprocessing monitor from CFS Inc. It was one of two early local teleprocessing packages for IBM's DOS/VSE environment. DUCS provided an interface and access method for programmers to 'talk' to monitors. Such access methods later became known as APIs.
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.
References
- 1 2 3 IBM System/360 Operating System Queued Telecommunications Access Method-Message Control Program (PDF). IBM. November 1968. C30-2005-2.
- ↑ IBM Operating System/360 Telecommunications: Preliminary Specifications (PDF). IBM. December 1965. C28-6553-2.
- ↑ OS Conversion Guide from QTAM or BTAM to TCAM (PDF). IBM. April 1971. GC30-2026-0.
