by Dinesh Thakur Category: Operating System

A command interpreter, or command processor, is that crucial part of the operating system software that interprets, or processes, the commands you give, and then carries them out for you. In DOS, the command processor is usually COMMAND. COM, although DOS lets you substitute another command processor if you want. This sounds pretty technical and scary, but it really isn't difficult.



 
by Dinesh Thakur Category: Operating System

Cipher textis information that has been changed into secret code for security reasons. A scheme for encoding messages to prevent them being read by unauthorized persons. It may have been enciphered,encrypted,or encoded, but it all means the same thing: it doesn't look like English so no one can use the information unless they have thepasswordto decode it.



 
by Dinesh Thakur Category: Operating System

BSD UNIX (Berkeley System Distribution) A family of versions of the UNIX operating system developed at the University of California at Berkeley in the early 1980s. BSD Unix version 4.0 was released in 1980 for DEC's VAX and PDP-ll computers. BSD Unix introduced many technical enhancements that have now been universally adopted, such as paged VIRTUAL MEMORY and built-in TCP/IP networking. It formed the basis for several commercial UNIX versions, including Sun's (prior to Solaris 2) and Hewlett Packard's ULTRIX.



 
by Dinesh Thakur Category: Operating System

Batch processing: The grouping together of several processing jobs to be executed one after another by a computer, without any user interaction. This is achieved by placing a list of the commands to start the required jobs into a BATCH FILE that can be executed as if it were a single program: hence batch processing is most often used in operating systems that have a COMMAND LINE user interface. Indeed, batch processing was the normal mode of working in the early days of mainframe computers, but modern personal computer applications typically require frequent user interaction, making them unsuitable for batch execution.



 
by Dinesh Thakur Category: Operating System

Parallel Processing Systems are designed to speed up the execution of programs by dividing the program into multiple fragments and processing these fragments simultaneously. Such systems are multiprocessor systems also known as tightly coupled systems. Parallel systems deal with the simultaneous use of multiple computer resources that can include a single computer with multiple processors, a number of computers connected by a network to form a parallel processing cluster or a combination of both.



 
by Dinesh Thakur Category: Operating System

Multiprocessor Operating System refers to the use of two or more central processing units (CPU) within a single computer system. These multiple CPUs are in a close communication sharing the computer bus, memory and other peripheral devices. These systems are referred as tightly coupled systems.



 
by Dinesh Thakur Category: Operating System

The real-time operating system used for a real-time application means for those applications where data processing should be done in the fixed and small quantum of time. It is different from general purpose computer where time concept is not considered as much crucial as in Real-Time Operating System. RTOS is a time-sharing system based on clock interrupts. Interrupt Service Routine (ISR) serve the interrupt, raised by the system. RTOS used Priority to execute the process. When a high priority process enters in system low priority process preempted to serve higher priority process. Real-time operating system synchronized the process. So that they can communicate with each other. Resources can be used efficiently without wastage of time.



 
by Dinesh Thakur Category: Operating System

Network Operating System is an operating system that includes special functions for connecting computers and devices into a local-area network (LAN) or Inter-network. Short form of Network Operating system is NOS. Some popular network operating systems are Novell Netware, Windows NT/2000, Linux, Sun Solaris, UNIX, and IBM OS/2. The network operating system which was first developed is Novell Netware. It was developed in 1983.



 
by Dinesh Thakur Category: Operating System

Distributed Operating System is a model where distributed applications are running on multiple computers linked by communications. A distributed operating system is an extension of the network operating system that supports higher levels of communication and integration of the machines on the network.



 
by Dinesh Thakur Category: Operating System

In earlier days, Computers was programmed to solve the problem. More prior day’s computer could perform only one job at a time. This computation resulted least CPU utilization. Most of time CPU was idle. To use CPU more efficiently, computer crossed many stages of evaluation.

In 1950 first operating system known as the batch operating system was introduced. Batch Operating System could execute a group of jobs in the form of a single deck of punched card.



 
by Dinesh Thakur Category: Operating System

A time sharing system allows many users to share the computer resources simultaneously. In other words, time sharing refers to the allocation of computer resources in time slots to several programs simultaneously. For example a mainframe computer that has many users logged on to it. Each user uses the resources of the mainframe -i.e. memory, CPU etc. The users feel that they are exclusive user of the CPU, even though this is not possible with one CPU i.e. shared among different users.



 
by Dinesh Thakur Category: Operating System

To overcome the problem of underutilization of CPU and main memory, the multiprogramming was introduced. The multiprogramming is interleaved execution of multiple jobs by the same computer.



 
by Dinesh Thakur Category: Operating System

To avoid the problems of early systems the batch processing systems were introduced. The problem of early systems was more setup time. So the problem of more set up time was reduced by processing the jobs in batches, known as batch processing system. In this approach similar jobs were submitted to the CPU for processing and were run together.

 
by Dinesh Thakur Category: Operating System

Following are the services provided by an operating system for the convenience of users:

  1. Program Execution

The purpose of computer system is to allow the users to execute programs in an efficient manner. The operating system provides an environment where the user can conveniently run these programs. The user does not have to worry about the memory allocation or de-allocation or any other thing because these things are taken care of by the operating system.



 
by Dinesh Thakur Category: Operating System

A computer system can be divided into five components; the hardware, the operating system, the utilities, the application programs and the end users. Following diagram shows the actual position of an operating system among these components.



 
by Dinesh Thakur Category: Operating System

Spooling - simultaneous peripheral operations on-line, spooling refers to as a process that putting jobs in a buffer or say spool, or temporary storage area, a special area in memory or on a disk where a device can access them when it is ready. Spooling is useful because devices access data at different rates.

 
by Dinesh Thakur Category: Operating System

Operating System is the System Software that makes the Computer work. We can say that an Operating System (OS) is Software that acts as an interface between you and the hardware. It not only contains drivers used to speak the hardware's language, but also offers you a very specific graphical user interface (GUI) to control the computer.



 
by Dinesh Thakur Category: Operating System

Real Time System : There is also a Operating System which is known as Real Time Processing System. In this Response Time is already fixed. Means time to Display the Results after Possessing has fixed by the Processor or CPU.

 
by Dinesh Thakur Category: Operating System

Marshalling is the process of gathering data and transforming it into a standard format before it is transmitted over a network so that the data can transcend network boundaries.

 
by Dinesh Thakur Category: Operating System

Memory partitioning is the way to distribute the Kernel and User Space Area in Memory.

Paging is actually a minimum memory, which can be swap in and swap out from Memory. In modern Server operating systems, we can use Multiple Page Size Support. That actually helps to tune OS performance, depending on type of applications.



 

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About Dinesh Thakur

Dinesh ThakurDinesh Thakur holds an B.SC (Computer Science), MCSE, MCDBA, CCNA, CCNP, A+, SCJP certifications. Dinesh authors the hugely popular blog. Where he writes how-to guides around Computer fundamental , computer software, Computer programming, and web apps. For any type of query or something that you think is missing, please feel free to Contact us.



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