1) Explain the main purpose of an operating system? Operating Top 50 Operating System Interview Questions & Answers .. Download PDF. OS Interview Questions. 1. What is an operating system? An operating system is a program that acts as an intermediary between the user and the computer. Contains Important Operating system Interview Questions with Answers and Questions based on Operating system, check your knowledge and test your Answers PDF | Interview Questions in Operating System | Operating System eBooks.

Operating System Interview Questions And Answers Pdf

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Operating Systems Interview Questions. 1 riacripwacose.cfumar, mail: Ans: An operating system is a program that acts as an intermediary between the user and the computer .. common variables, updating tables, writing a file and so on. Only one. Technical interview questions and answers section on "Operating Systems" with Operating Systems quiz questions with answers as PDF files and eBooks. + Operating System Interview Questions and Answers, Question1: Explain the main purpose of an operating system? Question2: What is demand paging?.

Questions When is a system in safe state?

The set of dispatchable processes is in a safe state if there exists at least one temporal order 11 in which all processes can be run to completion without resulting in a deadlock.

Questions What is cycle stealing?

The latter technique is called cycle stealing. Note that cycle stealing can be done only at specific break points in an instruction cycle. Questions What is meant by arm-stickiness? If one or a few processes have a high access rate to data on one track of a storage disk, then 13 they may monopolize the device by repeated requests to that track.

High-density multisurface disks are more likely to be affected by this than low density ones. Questions What are the stipulations of C2 level security? C 2 level security provides for: The repeated execution of a loop of code while waiting for an event to occur is called busy15 waiting. The C PU is not engaged in any real productive activity during this period, and the process does not progress toward completion. Questions Explain the popular multiprocessor thread-scheduling strategies.

Processes are not assigned to a particular processor. A global queue of 16 threads is maintained. Each processor, when idle, selects a thread from this queue. Note that load balancing refers to a scheme where work is allocated to processors on a more permanent basis. A set of related threads is scheduled to run on a set of processors at the same time, on a 1-to-1 basis. Group scheduling predated this strategy. Provides implicit scheduling defined by assignment of threads to processors.

For the duration of program execution, each program is allocated a set of processors equal in number to the number of threads in the program. Processors are chosen from the available pool. The number of thread in a program can be altered during the course of execution. Questions When does the condition 'rendezvous' arise? In message passing, it is the condition in which, both, the sender and receiver are blocked 17 until the message is delivered.

Questions What is a trap and trapdoor? Trapdoor is a secret undocumented entry point into a program used to grant access without 18 normal methods of access authentication. A trap is a software interrupt, usually the result of an error condition.

Questions What are local and global page replacements?

Local replacement means that an incoming page is brought in only to the relevant process' 19 address space. Global replacement policy allows any page frame from any process to be replaced. The latter is applicable to variable partitions model only. Seek time is the time required to move the disk arm to the required track. Rotational delay or 20 latency is the time it takes for the beginning of the required sector to reach the head.

Sum of seek time if any and latency is the access time. Time taken to actually transfer a span of data is transfer time. Questions Describe the Buddy system of memory allocation. Free memory is maintained in linked lists, each of equal sized blocks.

When some memory is required by a process, the block size of next higher order is chosen, and broken into two. Note that the two such pieces differ in address only in their kth bit. Such pieces are called buddies. When any used block is freed, the OS checks to see if its buddy is also free. If so, it is rejoined, and put into the original free-block linked-list.

Questions What is time-stamping? It is a technique proposed by Lamport, used to order events in a distributed system without 22 the use of clocks. This scheme is intended to order events consisting of the transmission of messages.

Each system 'i' in the network maintains a counter C i. In the second case, provisions are available for clients to create, access and update files. In asymmetric clustering, a machine is in a state known as hot standby mode where it does nothing but to monitor the active server.

Operating System Interview Questions & Answers

A thread is a basic unit of CPU utilization. In general, a thread is composed of a thread ID, program counter, register set, and the stack.

FCFS stands for First-come, first-served. It is one type of scheduling algorithm.

Implementation is managed by a FIFO queue. RR round-robin scheduling algorithm is primarily aimed for time-sharing systems. A circular queue is a setup in such a way that the CPU scheduler goes around that queue, allocating CPU to each process for a time interval of up to around 10 to milliseconds.

Deadlock situations occur when four conditions occur simultaneously in a system: Mutual exclusion; Hold and Wait; No preemption; and Circular wait. It gets its name from a banking system wherein the bank never allocates available cash in such a way that it can no longer satisfy the needs of all of its customers.

One is that it depends on how often a deadlock is likely to occur under the implementation of this algorithm.

The other has to do with how many processes will be affected by deadlock when this algorithm is applied. 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. With dynamic loading, a routine is not loaded until it is called. This method is especially useful when large amounts of code are needed in order to handle infrequently occurring cases such as error routines.

Overlays are used to enable a process to be larger than the amount of memory allocated to it.

The basic idea of this is that only instructions and data that are needed at any given time are kept in memory. Paging is a memory management scheme that permits the physical address space of a process to be noncontiguous.


What are the different operating systems? Batched operating systems 2. Multi-programmed operating systems 3.

Distributed operating systems 5. Real-time operating systems. Explain the concept of the batched operating systems? In batched operating system the users gives their jobs to the operator who sorts the programs according to their requirements and executes them.

This is time consuming but makes the CPU busy all the time. Explain the concept of the multi-programmed operating systems? A multi-programmed operating systems can execute a number of programs concurrently. The operating system fetches a group of programs from the job-pool in the secondary storage which contains all the programs to be executed, and places them in the main memory. This process is called job scheduling.

Then it chooses a program from the ready queue and gives them to CPU to execute. Explain the concept of the timesharing operating systems? It is a logical extension of the multi-programmed OS where user can interact with the program.

Commonly Asked Operating Systems Interview Questions | Set 1

The CPU executes multiple jobs by switching among them, but the switches occur so frequently that the user feels as if the operating system is running only his program. C Language Interview Questions 2. Data Structures Interview Questions 4. Operating System Interview Questions 6. I have finished my schooling and new to computer technology.

The question and answers are very useful for studies and interviews. Name required.Answer : Interrupts are part of a hardware mechanism that sends a notification to the CPU when it wants to gain access to a particular resource. Please use ide. What is virtual memory? What are short-term, long-term and medium-term scheduling? See the wiki page for an example and more details.

The users. Each system 'i' in the network maintains a counter C i. With pre-paging, pages other than the one demanded by a page fault are brought in. List the Coffman's conditions that lead to a deadlock.

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