INTERVIEW | TECHNICAL INTERVIEWS | OPERATING SYSTEM | OPERATING SYSTEM INTERVIEW QUESTION AND ANSWERS | 12 | WHAT ARE THE BENEFITS OF MULTITHREADED PROGRAMMING | WHAT IS CACHE-COHERENCY

Operating System Interview Question and Answers:

What are the benefits of multithreaded programming - What is cache-coherency

56. What are the benefits of multithreaded programming?

    Responsiveness

    Resources sharing

    Economy

    Utilization of multiprocessor architectures.


57. What is cache-coherency?

                In a multiprocessor system there exist several caches each may containing a copy of same variable A. Then a change in one cache should immediately be reflected in all other caches this process of maintaining the same value of a data in all the caches s called cache-coherency.

 

INTERVIEW | TECHNICAL INTERVIEWS | OPERATING SYSTEM | OPERATING SYSTEM INTERVIEW QUESTION AND ANSWERS | 11 | WHAT IS DRAM | WHAT ARE LOCAL AND GLOBAL PAGE REPLACEMENTS

Operating System Interview Question and Answers:

What is DRAM - What are local and global page replacements

51. What is DRAM?

                Dynamic Ram stores the data in the form of Capacitance, and Static RAM stores the data in Voltages.


52. What is a trap and trapdoor?

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


53. What is the difference between microkernel and macro kernel?

                Micro-Kernel : A micro-kernel is a minimal operating system that performs only the essential functions of an operating system. All other operating system functions are performed by system processes.

Monolithic : A monolithic operating system is one where all operating system code is in a single executable image and all operating system code runs in system mode.


54. What are the different functions of Scheduler?

                Scheduler deals with the problem of deciding which of the process in the ready queue is to be allocated the CPU. Short Term Schedulers, Long Term Schedulers.


55. What are local and global page replacements?

                Local replacement means that an incoming page is brought in only to the relevant process' address space. Global replacement policy allows any page frame from any process to be replaced. The latter is applicable to variable partitions model only.

INTERVIEW | TECHNICAL INTERVIEWS | OPERATING SYSTEM | OPERATING SYSTEM INTERVIEW QUESTION AND ANSWERS | 10 | WHAT ARE DEADLOCK PREVENTION TECHNIQUES | WHAT IS A DATA REGISTER AND ADDRESS REGISTER

Operating System Interview Question and Answers:

What are deadlock prevention techniques - What is a data register and address register

46. What are deadlock prevention techniques?

    Mutual exclusion

    Hold and wait

    No preemption

    Circular wait


47. What is the difference between Complier and Interpreter?

                An interpreter reads one instruction at a time and carries out the actions implied by that instruction. It does not perform any translation. But a compiler translates the entire instructions.

48. What is a Safe State and what is its use in deadlock avoidance?

                When a process requests an available resource, system must decide if immediate allocation leaves the system in a safe state. System is in safe state if there exists a safe sequence of all processes. Deadlock Avoidance : ensure that a system will never enter an unsafe state.


49. What is process synchronization?

                A situation, where several processes access and manipulate the same data concurrently and the outcome of the execution depends on the particular order in which the access takes place, is called race condition. To guard against the race condition we need to ensure that only one process at a time can be manipulating the same data. The technique we use for this is called process synchronization.


50. What is a data register and address register?

                Data registers - can be assigned to a variety of functions by the programmer. They can be used with any machine instruction that performs operations on data.

Address registers - contain main memory addresses of data and instructions or they contain a portion of the address that is used in the calculation of the complete addresses.

INTERVIEW | TECHNICAL INTERVIEWS | OPERATING SYSTEM | OPERATING SYSTEM INTERVIEW QUESTION AND ANSWERS | 09 | WHAT IS THE DIFFERENCE BETWEEN PRIMARY STORAGE AND SECONDARY STORAGE | WHAT IS THE STATE OF THE PROCESSOR WHEN A PROCESS IS WAITING FOR SOME EVENT TO OCCUR

Operating System Interview Question and Answers:

What is the difference between Primary storage and secondary storage - What is the state of the processor, when a process is waiting for some event to occur

41. What is the difference between Primary storage and secondary storage?

                Main memory - only large storage media that the CPU can access directly.

Secondary storage - extension of main memory that provides large nonvolatile storage capacity.


42. What is relative path and absolute path?

                Absolute path-- Exact path from root directory.

Relative path-- Relative to the current path.


43. What are the disadvantages of context switching?

                Time taken for switching from one process to other is pure over head. Because the system does no useful work while switching. So one of the solutions is to go for threading when ever possible.


44. What is context switching?

                Transferring the control from one process to other process requires saving the state of the old process and loading the saved state for new process. This task is known as context switching.


45. What is the state of the processor, when a process is waiting for some event to occur?

                Waiting state 

INTERVIEW | TECHNICAL INTERVIEWS | OPERATING SYSTEM | OPERATING SYSTEM INTERVIEW QUESTION AND ANSWERS | 08 WHAT IS A LONG TERM SCHEDULER AND SHORT TERM SCHEDULERS | WHAT IS STARVATION

What is a long term scheduler & short term schedulers - What is starvation

 Operating System Interview Question and Answers:

36. What is a long term scheduler & short term schedulers?

                Long term schedulers are the job schedulers that select processes from the job queue and load them into memory for execution.

The Short term schedulers are the CPU schedulers that select a process form the ready queue and allocate the CPU to one of them.

37. What are the different types of Real-Time Scheduling?
      Hard real-time systems required to complete a critical task within a guaranteed amount of time.
Soft real-time computing requires that critical processes receive priority over less fortunate ones.

38. What is fragmentation?

                Fragmentation occurs in a dynamic memory allocation system when many of the free blocks are too small to satisfy any request.

40. What is a device queue?

                A list of processes waiting for a particular I/O device is called device queue.

41. What is starvation ?

                Starvation is a resourcemanagement problem where a process does not get the resources it needs for a long time because the resources are being allocated to other processes.

INTERVIEW | TECHNICAL INTERVIEWS | OPERATING SYSTEM | OPERATING SYSTEM INTERVIEW QUESTION AND ANSWERS | 07 | WHAT IS A PROCESS - WHY THREAD IS CALLED AS A LIGHTWEIGHT PROCESS

Operating System Interview Question and Answers:

What is a process - Why thread is called as a lightweight process

31. What is a process?

      A program in execution is called a process. Or it may also be called a unit of work. A process needs some system resources as CPU time, memory, files, and i/o devices to accomplish the task. Each process is represented in the operating system by a process control block or task control block (PCB).Processes are of two types

Operating system processes

User processes

32. What are the different job scheduling in operating systems?

      Scheduling is the activity of the deciding when process will receive the resources they request.

FCFS --> FCSFS stands for First Come First Served. In FCFS the job that has been waiting the longest is served next.

Round Robin Scheduling-->Round Robin scheduling is a scheduling method where each process gets a small quantity of time to run and then it is preempted and the next process gets to run. This is called time-sharing and gives the effect of all the processes running at the same time

Shortest Job First --> The Shortest job First scheduling algorithm is a nonpreemptive scheduling algorithm that chooses the job that will execute the shortest amount of time.

Priority Scheduling-->Priority scheduling is a scheduling method where at all times the highest priority process is assigned the resource.

What is dual-mode operation?

                In order to protect the operating systems and the system programs from the malfunctioning programs the two mode operations were evolved

System mode

User mode.

33. What is dual-mode operation?

              In order to protect the operating systems and the system programs from the malfunctioning programs the two mode operations were evolved

System mode

User mode.

34. What are operating system services?

    Program execution

    I/O operations

    File system manipulation

    Communication

    Error detection

    Resource allocation

    Accounting

    Protection

35. Why thread is called as a lightweight process?

          It is called light weight process to emphasize the fact that a thread is like a process but is more efficient and uses fewer resources( n hence “lighter”)and they also share the address space.

INTERVIEW | TECHNICAL INTERVIEWS | OPERATING SYSTEM | OPERATING SYSTEM INTERVIEW QUESTION AND ANSWERS | 06 | WHAT ARE RESIDENCE MONITORS | WHAT ARE THE OPERATING SYSTEM COMPONENTS

Operating System Interview Question and Answers:

What are residence monitors _ What are the operating system components

26. What are residence monitors?
      Early operating systems were called residence monitors.


27. What is mutex?
      Mutex is a program object that allows multiple program threads to share the same resource, such as file access, but not simultaneously. When a program is started a mutex is created woth a unique name. After this stage, any thread that needs the resource must lock the mutex from other threads while it is using the resource. the mutex is set to unlock when the data is no longer needed or the routine is finished.


28. What is Marshalling?
      The process of packaging and sending interface method parameters across thread or process boundaries.
 

29. What are turnaround time and response time?
      Turnaround time is the interval between the submission of a job and its completion.
Response time is the interval between submission of a request, and the first response to that request.


30. What are the operating system components?
    Process management
    Main memory management
    File management
    I/O system management
    Secondary storage management
    Networking
    Protection system
    Command interpreter system