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

 

Figure: 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