by Dinesh Thakur Category: Operating System

Definition: A Scheduling Algorithm is the algorithm which tells us how much CPU time we can allocate to the processes.
These scheduling algorithms are either preemptive or non-preemptive.
Preemptive Scheduling Algorithms are those which are based on the priority of the processes. By preference, when a high priority process enters, it preempts a low priority process in between and executes the high priority process first.
Non-preemptive Scheduling Algorithms are those who can’t be preempted in between, i.e. we can not take control of CPU in between until the current process completes its execution.

 
by Dinesh Thakur Category: Operating System

Definition: System Software can be designed as the software in such a way so that it can control and work with computer hardware. It acts as an interface between the device and the end user.



 
by Dinesh Thakur Category: Operating System

Definition: Priority Scheduling is a scheduling process which is based on priority. In priority scheduling, the scheduler himself chooses the task priority, and the process which has the highest priority is processed first as compared to other processes.

Example: Shortest Job First (SJF) scheduling

 
by Dinesh Thakur Category: Operating System

DefinitionPreemptive Scheduling is defined as the scheduling which is done when the process changes from running state to ready state or from waiting for the state to ready state. In this, the resources are allocated to execute the process for a certain period. After this, the process is taken away in the middle and is placed in the ready queue its bursts time is left and this process will stay in ready line until it gets its turn to execute.

 
by Dinesh Thakur Category: Operating System

Definition: A Multi-user operating system is a computer operating system which allows multiple users to access the single system with one operating system on it. It is generally used on large mainframe computers.
Example: Linux, Unix, Windows 2000, Ubuntu, Mac OS etc.,
In the multi-user operating system, different users connected at different terminals and we can access, these users through the network as shown in the diagram.



 
by Dinesh Thakur Category: Operating System

Definition: Memory segmentation is the process in which we divide the primary memory of the computer into segments. It is a memory management technique. Each segment can be allocated to a process.
The segment table is the table which stores all the details about the segments which are further stored in one of the segments. Segment table contains two information about the segment: one is, the base address of the segment and other is, the length of the segment.



 
by Dinesh Thakur Category: Operating System

The operating system provides set functions to create, synchronize, control, execute the processes on the system. In the earlier time when the operating system was not available then every program required full hardware access or time for execution. To overcome this problem and used the CPU efficiently, the operating system introduced.



 
by Dinesh Thakur Category: Operating System

The software is a kind of programs that enable a user to perform some specific task or used to operate a computer. It directs all the peripheral devices on a computer system - what to do and how to perform work. Without Software, we can’t operate hardware and perform any calculations. A computer system can be divided into three components: the hardware, the software and the users. The software can be further divided into mainly two parts: Application software and System Software. Bare use of hardware is not easy, so to make it easy software is created.



 
by Dinesh Thakur Category: Operating System

Today Operating System can run multiple processes. But we know that only one process can be executed at the same time. Then to arrange and control the numerous processes in the system and utilize the CPU efficiently, some scheduling algorithm used by CPU.

 
by Dinesh Thakur Category: Operating System

Definition: The operating system provides us a graphic interface to give the command to the computer system. But system can’t understand these commands directly. Translation of code into binary language done by the core component of an operating system (OS), i.e., KERNEL. User deal with the lowest layer of kernel and then kernel deal with system.



 
by Dinesh Thakur Category: Operating System

What is Software: Computer software, or simply software, is a kind of programs that enable a user to perform some specific task or used to operate a computer. It directs all the peripheral devices on computer system - what to do and how to perform a task. PC Software plays a role of mediator between user and computer hardware. Without Software, a user can’t perform any task in digital computer.



 
by Dinesh Thakur Category: Operating System

Kernel and utilities

The operating system includes a number of routines (subroutines). the most important are the core or kernel. It is loaded into memory live at system initialization and contains many procedures needed to ensure system operation. Other routines, less critical, are called utilities.

The kernel of an operating system consists of four main parts: the manager tasks (or processes), the memory manager, and file manager IO Device Manager. It also has two auxiliary parts: charger operating system and shell.



 
by Dinesh Thakur Category: Operating System

Multitasking Systems

Most modern operating systems allow running multiple tasks both: a computer can, while executing a user program, read the data from a disk or display results on a terminal or printer. We talk about multi-tasking operating system or multi-programmed in this case.



 
by Dinesh Thakur Category: Operating System

An operating system basically performs three independent tasks: it allows load after each other programs, it emulates a virtual machine and manages resources. Specify each task.



 
by Dinesh Thakur Category: Operating System

OS/2 stands for operating system/2, an operating system that was developed by Microsoft C01poration and IBM, and now being improved and marketed exclusively by IBM. OS/2 runs on 286-, 386-, and 486-based IBM PCs and compatibles. OS/2 has many of the same commands as DOS, can read DOS disks, but it is more sophisticated than DOS. In particular, OS/2 is a multi-tasking, multi-threaded operating system. Multi-tasking means it can run more than one application at a time; multi-threaded means that a single program can perform multiple separate tasks at the same time.



 
by Dinesh Thakur Category: Operating System

MS-DOS (pronounced "em ess doss") stands for Microsoft disk operating system, the most widely-used operating system for IBM PC and compatible computers (an operating system is the master control software program that runs the computer itself). This means that MS-DOS is the most widely used computer operating system, period, since there are something like 80 to 100 million PCs in the world, and most of them use MS-DOS. There are at least two other versions of DOS that are compatible with MS-DOS (meaning they work the same way and run the same programs). So please see the definition for DOS for the whole story.



 
by Dinesh Thakur Category: Operating System

Computers are asked to store massive amounts of information on storage media such as floppy disks and hard disks. Long ago, the computer just saved all the files on the disk, and if you weren't careful, you could end up with a list of files so long you could strain your wrist just trying to scroll through them all! It was kind of like putting all the papers into your filing cabinet without folders.



 
by Dinesh Thakur Category: Operating System

Cooperative multitasking A MULTITASKING scheme under which each concurrently running program must at intervals voluntarily relinquish control of the CPU to the next program. Such programs must be specially written to suspend themselves in some non critical section and so, conversely, programs that are not so written cannot be multitasked. This contrasts with PRE-EMPTIVE MULTITASKING in which the OPERATING SYSTEM itself periodically suspends each task, so that any program may be multitasked. Apple's MACOS is a cooperative multitasking system, whereas UNIX and WINDOWS are preemptive.

 
by Dinesh Thakur Category: Operating System

If you have a PC you probably have a file named CONFIG.SYS on the disk you use to start, or boot, the computerA file that is automatically read at start up by the MS-DOS operating system used to load the DEVICE DRIVERS required by the various peripherals connected to the computer, and to set the correct configuration parameters for them. This file contains a variety of instructions used to customize the way your system works. Each time you start or restart the machine, the CONFIG.SYS file is read by the operating system (DOS or OS/2), which configures itself according to the instructions in the file. In DOS the typical CONFIG.SYS file starts with commands that tell the operating system how many files can be in use at anyone time, and how many buffers to create, like this:



 
by Dinesh Thakur Category: Operating System

In operating systems like DOS and Unix, and in many text-based or character mode programs, you control what's happening by typing commands on a command line. The command line is simply the line on the screen where you type your commands. The only way to control an operating system or a program that uses a command line interface like this is by typing commands-you don't get menus, dialog boxes, or buttons.



 

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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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