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Job Control (computing)
In computing job control refers to the control of multiple tasks or jobs on a computer system, ensuring that they each have access to adequate resources to perform correctly, that competition for limited resources does not cause a deadlock where two or more jobs are unable to complete, resolving such situations where they do occur, and terminating jobs that, for any reason, are not performing as expected. Job control has developed from the early days of computers where human operators were responsible for setting up, monitoring and controlling every job, to modern operating systems, which take on the bulk of the work of job control. Even with a highly sophisticated scheduling system, some human intervention is desirable. Modern systems permit their users to stop and resume jobs, to execute them in the foreground (with the ability to interact with the user) or in the background. Unix-like systems follow this pattern. History It became obvious to the early computer developers th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computing
Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes, and development of both hardware and software. Computing has scientific, engineering, mathematical, technological and social aspects. Major computing disciplines include computer engineering, computer science, cybersecurity, data science, information systems, information technology and software engineering. The term "computing" is also synonymous with counting and calculating. In earlier times, it was used in reference to the action performed by mechanical computing machines, and before that, to human computers. History The history of computing is longer than the history of computing hardware and includes the history of methods intended for pen and paper (or for chalk and slate) with or without the aid of tables. Computing is intimately tied to the representation of numbers, though mathematical conc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inter-process Communication
In computer science, inter-process communication or interprocess communication (IPC) refers specifically to the mechanisms an operating system provides to allow the processes to manage shared data. Typically, applications can use IPC, categorized as clients and servers, where the client requests data and the server responds to client requests. Many applications are both clients and servers, as commonly seen in distributed computing. IPC is very important to the design process for microkernels and nanokernels, which reduce the number of functionalities provided by the kernel. Those functionalities are then obtained by communicating with servers via IPC, leading to a large increase in communication when compared to a regular monolithic kernel. IPC interfaces generally encompass variable analytic framework structures. These processes ensure compatibility between the multi-vector protocols upon which IPC models rely. An IPC mechanism is either synchronous or asynchronous. Synchr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Terminal
A computer terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system. The teletype was an example of an early-day hard-copy terminal and predated the use of a computer screen by decades. Early terminals were inexpensive devices but very slow compared to punched cards or paper tape for input, yet as the technology improved and video displays were introduced, terminals pushed these older forms of interaction from the industry. A related development was time-sharing systems, which evolved in parallel and made up for any inefficiencies in the user's typing ability with the ability to support multiple users on the same machine, each at their own terminal or terminals. The function of a terminal is typically confined to transcription and input of data; a device with significant local, programmable data-processing capability may be called a "smart terminal" or fat client. A ter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unisys
Unisys Corporation is an American multinational information technology (IT) services and consulting company headquartered in Blue Bell, Pennsylvania. It provides digital workplace solutions, cloud, applications, and infrastructure solutions, enterprise computing solutions, and business process solutions for organizations around the world. History Founding Unisys was formed in 1986 through the merger of mainframe corporations Sperry and Burroughs, with Burroughs buying Sperry for $4.8 billion. The name was chosen from over 31,000 submissions in an internal competition when Christian Machen submitted the word "Unisys" which was composed of parts of the words ''united'', ''information'' and ''systems''. The merger was the largest in the computer industry at the time and made Unisys the second largest computer company with annual revenue of $10.5 billion. Michael Blumenthal became CEO and Chairman. Soon after the merger, the market for proprietary mainframe-class systems—t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rexx
Rexx (Restructured Extended Executor) is a programming language that can be interpreted or compiled. It was developed at IBM by Mike Cowlishaw. It is a structured, high-level programming language designed for ease of learning and reading. Proprietary and open source Rexx interpreters exist for a wide range of computing platforms; compilers exist for IBM mainframe computers. Rexx is a full language that can be used as a scripting, macro language, and application development language. It is often used for processing data and text and generating reports; these similarities with Perl mean that Rexx works well in Common Gateway Interface (CGI) programming and it is indeed used for this purpose. Rexx is the primary scripting language in some operating systems, e.g. OS/2, MVS, VM, AmigaOS, and is also used as an internal macro language in some other software, such as SPF/PC, KEDIT, THE and the ZOC terminal emulator. Additionally, the Rexx language can be used for scripting and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CLIST
CLIST (Command List) (pronounced "C-List") is a procedural programming language for TSO in MVS systems. It originated in OS/360 Release 20 and has assumed a secondary role since the availability of Rexx in TSO/E Version 2. The term CLIST is also used for command lists written by users of NetView. In its basic form, a CLIST program (or "CLIST" for short) can take the form of a simple list of commands to be executed in strict sequence (like a DOS batch file (*.bat) file). However, CLIST also features If-Then-Else logic as well as loop constructs. CLIST is an interpreted language. That is, the computer must translate a CLIST every time the program is executed. CLISTs therefore tend to be slower than programs written in compiled languages such as COBOL, FORTRAN, or PL/1. (A program written in a compiled language is translated once to create a "load module" or executable.) CLIST can read/write MVS files and read/write from/to a TSO terminal. It can read parameters from the cal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Time Sharing Option
Time Sharing Option (TSO) is an interactive time-sharing environment for IBM mainframe operating systems, including OS/360 MVT, OS/VS2 (SVS), MVS, OS/390, and z/OS. Use In computing, time-sharing is a design technique that allows many people to use a computer system concurrently and independently—without interfering with each other. Each TSO user is isolated; it appears to each one that they are the only user of the system. TSO is most commonly used by mainframe system administrators and programmers. It provides: * A text editor * Batch job support, including completion notification * Debuggers for some programming languages used on System/360 and later IBM mainframes * Support for other vendors' end-user applications, for example for querying IMS and DB2 databases TSO interacts with users in either a line-by-line mode or in a full screen, menu-driven mode. In the line-by-line mode, the user enters commands by typing them in at the keyboard; in turn, the system interprets t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Command Language
A command language is a language for job control (computing), job control in computing. It is a domain-specific language, domain-specific and interpreted language; common examples of a command language are shell script, shell or batch programming languages. These languages can be used directly at the command line, but can also automate tasks that would normally be performed manually at the command line. They share this domain—lightweight automation—with scripting language#Job control languages and shells, scripting languages, though a command language usually has stronger coupling (computer science), coupling to the underlying operating system. Command languages often have either very simple grammars or syntax (programming languages), syntaxes very close to natural language, to shallow the learning curve, as with many other domain-specific languages. See also * Command-line interface * In the Beginning... Was the Command Line * Batch processing * Job (computing) Notes Ext ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interactive Computing
In computer science, interactive computing refers to software which accepts input from the user as it runs. Interactive software includes commonly used programs, such as word processors or spreadsheet applications. By comparison, non-interactive programs operate without user intervention; examples of these include compilers and batch processing applications that are pre-programmed to run independently. Interactive computing focuses on real-time interaction ("dialog") between the computer and the operator, and the technologies that enable them. If the response of the computer system is complex enough, it is said that the system is conducting social interaction; some systems try to achieve this through the implementation of social interfaces. The nature of interactive computing as well as its impact on users, are studied extensively in the field of computer interaction. History of interactive computing systems Ivan Sutherland is considered the father of interactive computin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Batch Processing
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] |
Punched Card
A punched card (also punch card or punched-card) is a piece of stiff paper that holds digital data represented by the presence or absence of holes in predefined positions. Punched cards were once common in data processing applications or to directly control automated machinery. Punched cards were widely used through much of the 20th century in the data processing industry, where specialized and increasingly complex unit record equipment, unit record machines, organized into semiautomatic data processing systems, used punched cards for data input, output, and storage. The IBM 12-row/80-column punched card format came to dominate the industry. Many early digital computers used punched cards as the primary medium for input of both computer programs and Data (computing), data. While punched cards are now obsolete as a storage medium, as of 2012, some voting machines still used punched cards to record votes. They also had a significant cultural impact. History The idea of contr ... [...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] |
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