WHAT IS GRAPHIC DESIGN ? AND THEIR IMPORTANCE

What are operating system and their types?

An operating system is the most important software that runs on a computer.

An operating system is a set of system programs that control and co-ordinate the operations of computer system .or this is a system software that manage computer hardware and software.

This is interface between computer user and computer hardware. it is manage the computer memory and processes handling input and output ,controlling peripheral devices such as disk drives and printers.

Without an operating system, a computer is useless.

The first operating system built by Microsoft was DOS .MS-DOS originally written by Tim Paterson .it was built in 1981 by purchasing the 86DOS software from a Seattle company

Operating system provides the facilities to create, modification of program and data files using and editor .operating system access to the compiler for translating the user program from the high level language to machine level language. it provide the loader program to move the compiled program code to computer`s memory for execution.

Functions of operating system

MEMORY MANAGEMENT

Memory manage referred to management of primary memory or main memory .main memory is a large array of words or bytes where each word or byte has its own address main memory provides a fast storage that can be access directly bny7 the CPU so for a program to be executed, it must in the main memory.

Memory management keeps track of each and every memory location, regardless of either it is allocated to some process, it helps operating system to keep track of every memory location , irrespective of whether it is allocated to some process or it remain free .it helps protect different processed from each other. Operating system de-allocates the memory when the process no longer needs it or has been terminated.

PROCESSOR MANAGEMENR

In multiprogramming environment ,operating system decides which process gets the processor when and how much time .this function is called process scheduling .process scheduling is one of the most important functions of an operating system that supports that multiprogramming .

Process management helps operating system to create and delete processes. It also provides mechanism for synchronization and communication among processes .operating system keeps tracks of processor and status of processes program responsible for this task is known as traffic controller .operating system de-allocates processor when processor is no longer required.

DIVICE MANAGEMENT

Device management is one of the important functions of the operating system. Device management is responsible for managing all the hardware devices of the computer system. it may also include the management of the storage device as well as the management of all the input and output devices of the computer system . An operating system manages the device in a computer system with the help of device controllers and device driver. Each device in the computer system is equipped with the help of device controller. It manages devices communication via their respective drivers. While allocating the device to the various processes running on the computer system.

The other major responsibility of the device management function is to implement the application programming interface (API) the device controller used in the device management operation usually includes three different registers command ,status and data. Device management keeps tracks of all devices.

FILE MANAGEMENT

File management is one of the basic and important features of operating .it used to manage files of computer system .file management is defined as the process of manipulating files in a computer system , it management includes the process of creating , modifying and deleting the files. it manages all the file related activities such as organization storage , retrieval ,naming ,sharing and protection of files.

It specifies the logical method of file storage in a computer system. Some of the commonly used files systems include FAT and NTFS.

SECURITY MANAGEMENT

Security refers to providing a protection system to computer system resources such as CPU, memory, disk, software programs and most importantly data /information stored in a computer system. the operating system uses password protection to protect user data and similar other techniques .it also prevents unauthorized access to programs and user data.

TYPES OF OPERATING SYSTEM

BATCH OPERATING SYSTEM

By the early 1950`s the general motors research laboratories implemented the first single –stream batch processing systems .it ran a single job at a time and data were submitted in the form of groups or batches .batch operating system overcome the problem of setup time.

In this operating system there is no direct interaction between user and the computer. Batch operating system took the input on the punch card. Each punch card had the different form of data.

System executed the jobs one by one in batch. When one job from the batch executed then the second job has taken from it .and so on the process of placing the jobs in queue for execution is known as spooling.

As batch systems load less stress on processor and involve less user interaction so that is why we can use batch system in current days also.

ADVANTAGES OF BATCH OPERATING SYSTEM

Those operating system offer the high performance as the next job is executed as soon as the              

 Previous job is finished.

 To speed up the processing speed the batch process can partition in to the number of processes.

 Multiple users can share the batch system.

 The idle time for batch system is very less.

 The batch systems can manage large repeated work easy.

 It relieves the operator from the manual assignment of jobs.

DISADVANTAGES OF BATCH OPERATING SYSTEM

Difficult to debug program.

A job could enter an infinite loop.

It is some time costly.

The other jobs will have to wait for an unknown time if any job fails.

Due to lack of protection scheme one batch job can affect pending jobs.

MULTIPROGRAMMING OPERATING SYSTEM

To overcome the problem of underutilization of CPU and RAM, the concept of multiprogramming was introduced.

Sharing the processor, when two or more programs reside in memory at the same time is referred as multiprogramming

In note programming system when one program is waiting for O/I transfer there is another program ready to utilize the CPU. So it is possible for several jobs to share the time of the CPU. But it is important to note that multi programming is mot defined to be the execution of jobs at the same instance of time. Rather it does mean that there are a number of jobs available to the CPU and portion of one is executed then a segment of another and so on.

Multiprogramming operating systems monitor the stat of all active programs and system resources using memory management programs to ensure that the CPU is never idle, unless there are no jobs to process.

The whole operation is facilitated by multiprogramming operating system to maximize CPU utilization so that to reduce the idle time of the CPU. The idea is to keep the CPU busy for as long as possible.

   

MULTITASKING OPERATING SYSTEM

As the name itself suggests, multitasking refers to execution of multiple tasks at a time. In this technique multiple tasks, also known as processes, share common processing resources such as a CPU. As the system switches CPU rapidly from one user /program to the next, each user is given the impressions .that he /she has his /her own CPU, whereas actually one CPU is being shared among many users.

It is based on the concept of time sharing because multiple processed or tasks can be switched accordingly at a regular interval of time, so that the users get the idea that they performed concurrently.

The modern operating system, we are able to play mp3 music, edit documents in Microsoft word, surf the Google chrome all simultaneously, and this is accomplished by means of multitasking.

Multitasking operating system has well defined memory management because this operating system does not provide any type of permissions of unwanted programs to wasting the memory.

A time –shared operating system users the concept of CPU scheduling and multiprogramming to provide each user with a small portion of a time shared CPU.

TYPE OF MULTITASKING OPERATING SYSTEM

PREEMTIVE MULTITASKING OPERATING SYSTEM

In this operating system the process get preempted after time quantum. The operating system uses some criteria to decide for how long a process should execute before allowing another process to use the operating system .the mechanism of taking control of the operating system from one process and giving it to another process is called preempting or preemption.

COOPERATIVE MULTITASKING OPERATING SYSTEM

Cooperative multitasking also known as non preemptive multitasking. Is a style of computer multitasking in which the operating system never initiates a context switch from a running process to another process. In cooperative multitasking process scheduler never interrupts a process unexpectedly.

TIME SHARING OPERATING SYSTEM

Time sharing refers to the allocation of computer resources in time slots to several programs simultaneous. Time sharing is a logical extension of multiprogramming. In time sharing systems all the tasks are given specific time and task switching is very less so applications. Don`t get interrupted by it many applications can run at the same time. Time shared operating system allows multiple users to share computers simultaneously. each action or order at a time the share system becomes similar ,so only a little CPU time is required for each user  as the system rapidly switches form one user to another ,each user is given the impression that the entire computer system is dedicated to its use , although it is being shared among multiple users.

Time sharing system is better way to run a business having lot of tasks to be done and no task gets interrupted by the system each task and each user get its time. The tasks which are near to end get more attention so that new tasks can get time.

DISTRIBUTED OPERATING SYSTEM

A distributed operating system is software over a collection of independent networked communicational nodes .a distributed operations is collection of independent computers that appear to the users of the system as a single computer.

In such a system multiple resources work together to deliver the required processing speed and the operating system takes care of maintaining the system and overall maintenance. in distributed system computers are not independent but interconnected by a high speed network.

The distributed as involves a collection of autonomous computer system, capable of communicating and cooperating with each other through a LAN/WAN. A distributed operating system provides a virtual machine abstraction to its users and wide sharing of resources likes as computational capacity. I/O and files etc.

MULTIPROCESSING OPERATING SYSTEM

Multiprocessing refers to computer systems ability to support more than one process (program) at the time .each CPU contains a copy of the operating system and these copies communicate with one another to coordinate operations.

Multiprocessor operating system allow ,the multiple processors and these processors are connected with physical memory, computer buses clocks and peripherals system .multiprocessor system uses the two types of memory modules such as shared memory and distributed shared memory .

Multiprocessor O/S gets high performance due top parallel processing in this system single job is divided into various same small jobs and execute them like as parallel nature.

Multiprocessor system are used when users need extremely high processing speed to process a high volume of data , in most of the cases such as satellite processing deep data analysis and weather forecasting. The main advantages of multiprocessor system are to get more work done in a shorter period of time.

REAL TIME OPERATING SYSTEM

A real time operating system is defined as a data processing system in which the time interval required to process and respond to inputs is so small that it controls the environments. It is used for a real time application where data processing should be dome in the fixed and small quantum of time.

The time taken by the system to respond to an input and display of required updated information in termed as the response time. So in this method the response time very less as compared to online processing.

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