In this post we will learn Operating System(OS) Interview Questions which every IT developer must have knowledge on these Q & A. These questions and answers come across Technical Written Test also. Let us see what are those Questions and Answers as follows..
1) What is Operating System?
Ans: An Operating System is a software program that enables the computer hardware to communicate and operate with the computer software. Without a computer Operating system, a computer would be useless.
2) What are the different Operating Systems?
Ans: There are different types OS they are
1) Multi-programming OS
2) Distributed OS
3)Batched OS
4)Time-sharing OS
5)Real-time OS
3) Why paging is used in OS?
Ans: Paging is solution to external fragmentation problem which is to permit the logical address space of a process to be noncontinuous,thus allowing a process to be allocating physical memory wherever the latter is available.
4) What is the state of the processor,when a process is waiting for some event to occur?
Ans: The state of the processor is : Waiting state
5) What is Virtual Memory?
Ans: Virtual Memory is hardware technique where the system appears to have more memory that it actually does. This is done by time-sharing ,the physical memory and storage parts of the memory one disk when they are not actively being used.
6) What is fragmentation?
Ans: Fragmentation occurs in a dynamic memory allocation system when many of the free blocks are too small to satisfy any request.
7) What is the cause of thrashing? How does the system detect thrashing?
Ans: Once it detects thrashing,what can the system do to eliminate this problem? Thrashing is caused by under allocation of the minimum number of pages required by a process,forcing it to continuously page fault. The system can detect thrashing by evaluating the level of CPU utilization as compared to the level of multi programming. It can be eliminated by reducing the level of multi programming.
8) While running DOS on PC,which command would be used to duplicate the entire diskette?
Ans: This command will be use to duplicate the entire diskette diskcopy.
9) What is cache-memory?
Ans: Cache memory is random access memory(RAM) that a computer microprocessor can access more quickly that it can access regular RAM. As the microprocessor process data,it looks first in the cache memory and if if finds the data there(from the previous reading of data). It does not have to do the more time-consuming reading of data from larger memory.
10) What is Kernal?
Ans: Kernal is the core and essential part of computer operating system that provides basic services for all parts of OS.
11) What is a process?
Ans: A program in execution is called a process or it may be called unit of work. A process needs some system resources as CPU time,memory,files and I/O devices to accomplish the task.
12) What is semaphore?
Ans: Semaphore is a variable,whose status reports common resources,Semaphore is of two types one is Binary semaphore and other is Counting semaphore.
13) What is deadlock?
Ans: Deadlock is a situation or condition where two processes are waiting for each other to complete so that they can start. This result both the processes to hang
14) What are system calls?
Ans: System calls provide the interface between process and the OS. System calls for modern Microsoft windows platforms are part of the win 32 API. Which is available for all the compilers written for Microsoft Windows.
15) What are the states of Process?
Ans: There are 5 states of Process. They are
1) NEW
2) Running
3) Waiting
4) Ready
5) Terminated
16) What is the Real-Time System?
Ans: A Real-Time process is a process that must respond to the events within a certain time period. A real time operating system is an OS that can run real time processes successfully.
17) What is FCFS?
Ans: FCFS stands for First-come First-served is one type of scheduling algorithm.In this Scheme, the process that requests the CPU first is allocated the CPU first,implementation is managed by FIFO queue.
18) What is logical and physical address space?
Ans: Logical address refers to the address that is generated by the CPU. On the other hand,physical address refers to the address that is seen by the memory unit.
19) What is the basic function of Paging?
Ans: Paging is a memory management scheme that permits the physical address space.
20) What is bounded-buffer problem?
Ans: Assume that a pool consists of n buffers each capable of holding one item.The semaphore provides mutual exclusion for accesses to the buffer pool and is initialized to the value 1.The empty and full semaphores count the number of empty and full buffers, respectively. Empty is initialized to n, and full is initialized to 0.
1) What is Operating System?
Ans: An Operating System is a software program that enables the computer hardware to communicate and operate with the computer software. Without a computer Operating system, a computer would be useless.
2) What are the different Operating Systems?
Ans: There are different types OS they are
1) Multi-programming OS
2) Distributed OS
3)Batched OS
4)Time-sharing OS
5)Real-time OS
3) Why paging is used in OS?
Ans: Paging is solution to external fragmentation problem which is to permit the logical address space of a process to be noncontinuous,thus allowing a process to be allocating physical memory wherever the latter is available.
4) What is the state of the processor,when a process is waiting for some event to occur?
Ans: The state of the processor is : Waiting state
5) What is Virtual Memory?
Ans: Virtual Memory is hardware technique where the system appears to have more memory that it actually does. This is done by time-sharing ,the physical memory and storage parts of the memory one disk when they are not actively being used.
6) What is fragmentation?
Ans: Fragmentation occurs in a dynamic memory allocation system when many of the free blocks are too small to satisfy any request.
7) What is the cause of thrashing? How does the system detect thrashing?
Ans: Once it detects thrashing,what can the system do to eliminate this problem? Thrashing is caused by under allocation of the minimum number of pages required by a process,forcing it to continuously page fault. The system can detect thrashing by evaluating the level of CPU utilization as compared to the level of multi programming. It can be eliminated by reducing the level of multi programming.
8) While running DOS on PC,which command would be used to duplicate the entire diskette?
Ans: This command will be use to duplicate the entire diskette diskcopy.
9) What is cache-memory?
Ans: Cache memory is random access memory(RAM) that a computer microprocessor can access more quickly that it can access regular RAM. As the microprocessor process data,it looks first in the cache memory and if if finds the data there(from the previous reading of data). It does not have to do the more time-consuming reading of data from larger memory.
10) What is Kernal?
Ans: Kernal is the core and essential part of computer operating system that provides basic services for all parts of OS.
11) What is a process?
Ans: A program in execution is called a process or it may be called unit of work. A process needs some system resources as CPU time,memory,files and I/O devices to accomplish the task.
12) What is semaphore?
Ans: Semaphore is a variable,whose status reports common resources,Semaphore is of two types one is Binary semaphore and other is Counting semaphore.
13) What is deadlock?
Ans: Deadlock is a situation or condition where two processes are waiting for each other to complete so that they can start. This result both the processes to hang
14) What are system calls?
Ans: System calls provide the interface between process and the OS. System calls for modern Microsoft windows platforms are part of the win 32 API. Which is available for all the compilers written for Microsoft Windows.
15) What are the states of Process?
Ans: There are 5 states of Process. They are
1) NEW
2) Running
3) Waiting
4) Ready
5) Terminated
16) What is the Real-Time System?
Ans: A Real-Time process is a process that must respond to the events within a certain time period. A real time operating system is an OS that can run real time processes successfully.
17) What is FCFS?
Ans: FCFS stands for First-come First-served is one type of scheduling algorithm.In this Scheme, the process that requests the CPU first is allocated the CPU first,implementation is managed by FIFO queue.
18) What is logical and physical address space?
Ans: Logical address refers to the address that is generated by the CPU. On the other hand,physical address refers to the address that is seen by the memory unit.
19) What is the basic function of Paging?
Ans: Paging is a memory management scheme that permits the physical address space.
20) What is bounded-buffer problem?
Ans: Assume that a pool consists of n buffers each capable of holding one item.The semaphore provides mutual exclusion for accesses to the buffer pool and is initialized to the value 1.The empty and full semaphores count the number of empty and full buffers, respectively. Empty is initialized to n, and full is initialized to 0.
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