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JES2
The Job Entry Subsystem (JES) is a component of IBM's MVS mainframe operating systems that is responsible for managing batch workloads. In modern times, there are two distinct implementations of the Job Entry System called JES2 and JES3. They are designed to provide efficient execution of batch jobs. Job processing is divided into several phases to provide parallelism through pipelining. These phases include input processing where jobs are read and interpreted, the execution phase where jobs run, and output processing where job output is printed or stored on DASD. Jobs that are in the same phase of execution are usually said to reside on a particular queue; for example, jobs that are currently executing are on the execution queue. To improve I/O efficiency, JES performs spooling, which provides multiple jobs with simultaneous access to a common storage volume. JES uses a structure called a ''checkpoint'' to backup information about currently executing jobs and their associat ... [...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] |
Job Control Language
Job Control Language (JCL) is a name for scripting languages used on IBM mainframe operating systems to instruct the system on how to run a batch job or start a subsystem. More specifically, the purpose of JCL is to say which programs to run, using which files or devices for input or output, and at times to also indicate under what conditions to skip a step. Parameters in the JCL can also provide accounting information for tracking the resources used by a job as well as which machine the job should run on. There are two distinct IBM Job Control languages: * one for the operating system lineage that begins with DOS/360 and whose latest member is z/VSE; and * the other for the lineage from OS/360 to z/OS, the latter now including JES extensions, Job ''Entry'' Control Language (JECL). They share some basic syntax rules and a few basic concepts, but are otherwise very different. The VM operating system does not have JCL as such; the CP and CMS components each have command ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM System/370
The IBM System/370 (S/370) is a model range of IBM mainframe computers announced on June 30, 1970, as the successors to the System/360 family. The series mostly maintains backward compatibility with the S/360, allowing an easy migration path for customers; this, plus improved performance, were the dominant themes of the product announcement. In September 1990, the System/370 line was replaced with the System/390. Evolution The original System/370 line was announced on June 30, 1970, with first customer shipment of the Models 155 and 165 planned for February 1971 and April 1971 respectively. The 155 first shipped in January 1971. System/370 underwent several architectural improvements during its roughly 20-year lifetime. The following features mentioned in Principles of Operation are either optional on S/360 but standard on S/370, introduced with S/370 or added to S/370 after announcement. *Branch and Save *Channel Indirect Data Addressing *Channel-Set Switching *Clear I/O *Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Job Entry Subsystem 1
Job Entry Subsystem (JES), aka Job Entry Subsystem 1 (JES1), was released by IBM as an integral part of OS/VS1 as an enhancement to the basic functions that users of VS1's predecessor, MFT, had. History IBM proclaimed JES1 to be "the single most important addition" to the job scheduling provided by VS1. IBM Systems Journal defined JES1's services as Spooling and scheduling, adding "Its three major components are peripheral services, central services, and queue management." JES1 was not popular, because HASP and ASP users often had made local modifications (edits), and wanted to retain their investment. Features JES1 permitted operators to submit batch jobs from local unit record equipment. In addition, Remote Entry Service (RES) permitted remote operators to submit jobs from remote sites to JES. The printed and punched output of jobs running on OS/VS1, whether submitted locally or remotely, is handled by JES and may be routed to local devices, to the originating site or to anoth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spooling
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. Spooling is a co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SDSF
The System Display and Search Facility (SDSF) component of IBM's mainframe operating system, z/OS, is an interactive user interface that allows users and administrators to view and control various aspects of the mainframe's operation and system resources. Some of the information displayed in SDSF includes Batch job output, Unix processes, scheduling environments, and the status of external devices such as printers and network lines. SDSF is primarily used to access batch and system log files and dumps. History When it was a field-developed program offering, SDSF was known as the SPOOL Display and Search Facility The word ''SPOOL'' was changed to ''System'' when it became a program product in the late 1980s. With z/OS Release 1.9 SDSF supports a REXX interface, allowing batch programs to use SDSF facilities. This support includes stem variables containing SDSF-originated information. Prior to z/OS Release 1.10, SDSF was only supported for use with JES2 and not JES3, althou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Batch Job
Computerized batch processing is a method of running software programs called jobs in batches automatically. While users are required to submit the jobs, no other interaction by the user is required to process the batch. Batches may automatically be run at scheduled times as well as being run contingent on the availability of computer resources. History The term "batch processing" originates in the traditional classification of methods of production as job production (one-off production), batch production (production of a "batch" of multiple items at once, one stage at a time), and flow production (mass production, all stages in process at once). Early history Early computers were capable of running only one program at a time. Each user had sole control of the machine for a scheduled period of time. They would arrive at the computer with program and data, often on punched paper cards and magnetic or paper tape, and would load their program, run and debug it, and carry off their ou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM System/360 Model 50
The IBM System/360 Model 50 is a member of the IBM System/360 family of computers. The Model 50 was announced in April 1964 with the other initial models of the family, and first shipped in August 1965 to the Bank of America. Models There are four models of the 360/50. They vary by the amount of core memory with which the system is offered. The F50, or 2050F is equipped with 65,536 bytes, the G50 has 131,072 bytes, the H50 262,144 bytes, and the I50 524,288 bytes. The system can also attach IBM 2361 Large Capacity Storage (LCS) modules which provide up to 8,388,608 bytes of additional storage, however with a considerably slower memory cycle time of 8 microseconds compared to the 2 microseconds of processor storage. Relative performance The system has a CPU cycle time of 500 nanoseconds, 25% faster than the Model 40 and 40% slower than the Model 65. Processor storage is magnetic core memory that transfers four bytes per 2 microsecond cycle. It has "protected" and "local" core ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Job Scheduling
A job scheduler is a computer application for controlling unattended background program execution of jobs. This is commonly called batch scheduling, as execution of non-interactive jobs is often called batch processing, though traditional ''job'' and ''batch'' are distinguished and contrasted; see that page for details. Other synonyms include batch system, distributed resource management system (DRMS), distributed resource manager (DRM), and, commonly today, workload automation (WLA). The data structure of jobs to run is known as the job queue. Modern job schedulers typically provide a graphical user interface and a single point of control for definition and monitoring of background executions in a distributed network of computers. Increasingly, job schedulers are required to orchestrate the integration of real-time business activities with traditional background IT processing across different operating system platforms and business application environments. ''Job scheduling'' s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Object Code
In computing, object code or object module is the product of a compiler. In a general sense object code is a sequence of statements or instructions in a computer language, usually a machine code language (i.e., binary) or an intermediate language such as register transfer language (RTL). The term indicates that the code is the goal or result of the compiling process, with some early sources referring to source code as a "subject program". Details Object files can in turn be linked to form an executable file or library file. In order to be used, object code must either be placed in an executable file, a library file, or an object file. Object code is a portion of machine code that has not yet been linked into a complete program. It is the machine code for one particular library or module that will make up the completed product. It may also contain placeholders or offsets, not found in the machine code of a completed program, that the linker will use to connect everything toget ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Source Code
In computing, source code, or simply code, is any collection of code, with or without comments, written using a human-readable programming language, usually as plain text. The source code of a program is specially designed to facilitate the work of computer programmers, who specify the actions to be performed by a computer mostly by writing source code. The source code is often transformed by an assembler or compiler into binary machine code that can be executed by the computer. The machine code is then available for execution at a later time. Most application software is distributed in a form that includes only executable files. If the source code were included it would be useful to a user, programmer or a system administrator, any of whom might wish to study or modify the program. Alternatively, depending on the technology being used, source code may be interpreted and executed directly. Definitions Richard Stallman's definition, formulated in his 1989 seminal li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
