Operating System: The Soul of Computer

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Operating System: The Soul of Computer

Article by Subhash Kumar

Operating System: The Soul of Computer

Operating System Operating System-is the software component of a computer system that is responsible for the management and coordination of activities and the sharing of the resources of the computer. The operating system (OS) acts as a host for application programs that are run on the machine. As a host, one of the purposes of an operating system is to handle the details of the operation of the hardware. This relieves application programs from having to manage these details and makes it easier to write applications. Almost all computers, including hand-held computers, desktop computers, supercomputers, and even modern video game Consoles, use an operating system of some type.

Types of Operating System Operating systems can be classified as follows: * Multi-user : Allows two or more users to run programs at the same time. Some operating systems permit hundreds or even thousands of concurrent users. * Multiprocessing : Supports running a program on more than one CPU. * Multitasking : Allows more than one program to run concurrently. * Multithreading : Allows different parts of a single program to run concurrently. * Real time: Responds to input instantly. General-purpose operating systems, such as DOS and UNIX, are not real-time.

For PCs, the most popular operating systems are DOS, OS/2, and Windows, but others are available, such as Linux.. As a user, you normally interact with the operating system through a set of commands. For example, the DOS operating system contains commands such as COPY and RENAME for copying files and changing the names of files, respectively. The commands are accepted and executed by a part of the operating system called the command processor or command line interpreter. Graphical user interfaces allow you to enter commands by pointing and clicking at objects that appear on the screen.

The main advantages of an operating system include: 1. Allows multiple programs to run concurrently. 2. Simplifies the programming of application software because the program does not have to manage the hardware. The operating systems manages all hardware and the interaction of software. It also gives the program a high level interface to the hardware and ways of interacting with other programs. Functions Provided by the Operating System

* User Interface All graphics based today, the user interface includes the windows, menus and method of interaction between you and the computer. Prior to the Mac, Windows and Motif (Unix) interfaces, all interaction was based on commands entered by the user. Operating systems may support optional interfaces (different shells) for different functionality and appearance.

* Job Management Job management controls the order and time in which programs are run and is more sophisticated in the mainframe environment where scheduling the daily work has always been routine. IBM’s job control language (JCL) was developed decades ago. In a desktop environment, batch files can be written to perform a sequence of operations which can be scheduled to start at a given time.

* Task Management Multitasking, which is the ability to simultaneously execute multiple programs, is available in all operating systems today. Critical in the mainframe and large server environment, applications can be prioritized to run faster or slower depending on their purpose. In the desktop world, multitasking is necessary just for keeping several applications open at the same time so you can bounce back and forth among them. * Data Management Data management keeps track of the data on disk, tape and optical storage devices. The application program deals with data by file name and a particular location within the file. The operating system’s file system knows where that data are physically stored (which sectors on disk) and interaction between the application and operating system is through the programming interface. Whenever an application needs to read or write data, it makes a call to the operating system.

* Device Management Device management controls peripheral devices by sending those commands in their own proprietary language. The software routine that knows how to deal with each device is called a “driver.” The operating system contains all the drivers for the peripherals attached to the computer. When a new peripheral is added, that device’s driver is installed into the operating system.

* Security Multi-user operating systems provide password protection to keep unauthorized users out of the system. Large operating systems also maintain activity logs and accounting of the user’s time for billing purposes. They also provide backup and recovery routines for starting over in the event of a system failure.For more details Click here

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JCL question by pramod r: how can i run mainframe cobol and jcl in my PC(without internet)?
could u suggest me any tools and their links to download? i mean simulation tools for mainframe envt.

JCL best answer:

Answer by Prasun D
Use any simulator…like Hercules