Information Management Function Of An Operating System.

Q5. Explain the information management function of an operating system.

Ans. A computer system works with ‘Information’. It stores information, processes information, provides information etc. Thus managing this information is also an important and necessary task performed by OS. To support this function, OS’s have one component called ‘Information Management Component’. This information management component of OS is structured as follows:

  • Physical IOCS (Input-Output Control System) is responsible for device management and for ensuring device independence. It provides a basic capability for the programs to perform their own IO, without involving themselves with the intricacies of device handling.
  • Logical IOCS is responsible for efficient organization and access of data on IO devices. It provides basic capabilities for file definition, choice of data organization and access methods.
  • File System is responsible for protection and controlled sharing of files.
Figure: Hierarchy Of Information Management Modules.
  1. The Physical IOCS and IO Organization

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Virtual Storage Technique

Q4. Explain the virtual storage technique describing both the approaches.

Ans. A program can be stored at non contiguous locations, suppose even if we use all available free memory areas still the program cannot be loaded into the main storage because the total free memory is still less than the size of the program. To solve such a problem, we require a technique with which a program can still be executed even if all of it is not loaded in the memory. Virtual storage helps one perform such an execution. Two main approaches to virtual storage are

  • program-paging
  • program-segmentation

In Paging, the computer system is responsible for splitting a program into program segments called pages whereas in segmentation approach, the programmer identifies the logical entities in the program and declares them as program components.

Let us consider both of the approaches one by one.

  • Virtual Storage Using Paging

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Storage Management Functions Of An Operating System.

Q3. Explain the Storage Management functions of an operating system.

Ans. The working of a modern computer system, memory plays a central role. Both CPU and Input/output system interact with memory. Memory is a large array of words or bytes, each with its own address. The CPU reads from and writes to specific memory addresses.

Figure: Memory plays a central role in Computer System

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Processor Management Functions Of An Operating System.

Q2. Explain the processor management functions of an operating system.

Ans. As the name itself suggests, Processor Management means managing the process or processor that is, the CPU. Therefore, this very function is also termed as CPU Scheduling.

Multiprogramming, undoubtedly, improves the overall efficiency of the computer system by getting more work done in less time as the CPU may be shared among a number of active programs which are present in the memory at the same time. While CPU is executing a job, it has to wait for the job; if the job requires certain Input/output operation, the CPU waits for the Input/output operation to get over and that wait time is CPU’s idle time. In place of making CPU sit idle, another job takes over the use of CPU, increasing efficiency thereby and reducing CPU idle time.

The benefits of multiprogramming are as follow:

  • Increased CPU utilization
  • Higher total job throughput

Throughput is the amount of work accomplished in a given time interval, for example, 15 jobs per hour.

Throughput is an important measure of system performance. It is calculated as follow:

Throughput = (The number of jobs completed) / (Total time taken to complete the jobs)

Another important factor that influences throughput is priority assigned to different jobs that is, job scheduling.

  1. Job Scheduling

Job scheduling not only assign priority to jobs but also admits new jobs for processing at appropriate times. Before we start with job scheduling techniques, let us first understand basic terminology. Read More …

Working Of Operating System As A Resource Manager.

Q1. Explain the working of operating system as a resource manager.

Ans. Modern computers consist of processors, memories, timers, disks, mice, network interfaces, printers, and a wide variety of other devices. In the alternative view, the job of the operating system is to provide for an orderly and controlled allocation of the processors, memories, and input/output devices among the various programs competing for them.

When a computer (or network) has multiple users, Read More …

Operating System is called a Resource Manager

Q18. The operating system is called a resource manager. List four distinct resources of the computer system. What are the general functions that the OS perform for these resources?

Ans. An operating system is an important component of a computer system which controls all other components of the computer system. Major components of a computer system are:

  1. The Hardware
  2. The Operating System
  3. The Application program routines (compiler, linker, database management systems, utility programs)
  4. The Humanware (users)

Where hardware provides the basic computing resources, the application program routines define the ways in which these resources are used to solve the computing problems of the users and the Operating System  controls and coordinates the use of the hardware among the various application programs for the various users.

Concept of Virtual Storage

Q17. Explain the concept of virtual storage.

Ans. A program can be stored at non contiguous locations, suppose even if we use all available free memory areas still the program cannot be loaded into the main storage because the total free memory is still less than the size of the program. To solve such a problem, we require a technique with which a program can still be executed even if all of it is not loaded in the memory. Virtual storage helps one perform such an execution. Two main approaches to virtual storage are

  • program-paging
  • program-segmentation

Functions Performed By An Operating System As Memory Manager

Q16. Explain briefly the functions performed by an operating system as memory manager?

Ans. In the working of a modern computer system, memory plays a central role. Both CPU and Input/output system interact with memory. Memory is a large array of words or bytes, each with its own address. The CPU reads from and writes to specific memory addresses.

 

Memory Plays a central role in Computer System
Memory plays a central role in Computer System

 

A program must be assigned some memory area and loaded into memory in order to be executed. As the program executes, it accesses program instructions and data from memory by generating addresses of the allocated memory. When the program terminates, its memory space is declared free, and the next program may be given the same memory area. There can be many user programs loaded in the memory along with system programs and operating system.

 

 

Functions Performed By An Operating System As Processor Manager

Q15.Explain briefly the functions performed by an operating system as processor manager?

Ans. As the name itself suggests, Processor Management means managing the process or processor that is, the CPU. Therefore, this very function is also termed as CPU Scheduling.

Multiprogramming, undoubtedly, improves the overall efficiency of the computer system by getting more work done in less time as the CPU may be shared among a number of active programs which are present in the memory at the same time. While CPU is executing a job, it has to wait for the job; if the job requires certain Input/output operation, the CPU waits for the Input/output operation to get over and that wait time is CPU’s idle time. In place of making CPU sit idle, another job takes over the use of CPU, increasing efficiency thereby and reducing CPU idle time.

The benefits of multiprogramming are as follow:

  • Increased CPU utilization
  • Higher total job throughput

Concept of Process

Q14. Clearly define the concept of a process. Can different functions/subroutine of an HLL program be called processes?

Ans. Process is a program in execution. Job and Process are the terms which are almost used interchangeably.

Yes, different functions/subroutine of an HLL program can be called processes when they are in execution.