CS8493 Operating System

35 flashcards · Computer Science · by Mythili T

  1. Which of the following is not an operating system? Oracle

    Windows Linux Oracle DOS

  2. 2.When was the first operating system developed ? 1950

    The first operating system was developed in the early 1950's. It was also called a single-stream batch processing system because it presented data in groups.

  3. 3.Which of the following is the extension of Notepad? .txt

    The .txt file extension is a standard text document extension that contains the unformatted text. It is the default file extension for the notepad.

  4. 4.What is an operating system?

    Operating system acts as interface between user and computer hardware.It is the most important part of a computer system without it computer is just like a box.

  5. 5.What are the different operating systems?

    Batched operating systems Distributed operating systems Time Sharing operating systems Multi-programmed operating systems Real-time operating systems

  6. 6.What is a real-time system?

    Real-time system is used in the case when rigid-time requirements have been placed on the operation of a processor. It contains a well defined and fixed time constraints.

  7. 7.What is kernel?

    Kernel is the part of OS which handles all details of sharing resources and device handling. - It can be considered as the core of OS which manages the core features of an OS. - Its purpose is to handle the communication between software and hardware - Its services are used through system calls. - A layer of software called shell wraps around the Kernel.

  8. 8.What do you mean by a process?

    An executing program is known as process. There are two types of processes: Operating System Processes User Processes

  9. 9.What are the different states of a process?

    A list of different states of process: New Process Running Process Waiting Process Ready Process Terminated Process

  10. 10.What is the difference between micro kernel and macro kernel?

    Micro kernel: micro kernel is the kernel which runs minimal performance affecting services for operating system. In micro kernel operating system all other operations are performed by processor. Macro Kernel: Macro Kernel is a combination of micro and monolithic kernel.

  11. 11.What is the use of paging in operating system?

    Paging is used to solve the external fragmentation problem in operating system. This technique ensures that the data you need is available as quickly as possible.

  12. 12.What is the concept of demand paging?

    Demand paging specifies that if an area of memory is not currently being used, it is swapped to disk to make room for an application's need.

  13. 13.What is virtual memory?

    Virtual memory is a very useful memory management technique which enables processes to execute outside of memory. This technique is especially used when an executing program cannot fit in the physical memory.

  14. 14.What is thrashing?

    Thrashing is a phenomenon in virtual memory scheme when the processor spends most of its time in swapping pages, rather than executing instructions.

  15. 15.What are the differences between paging and segmentation?

  16. 16.What are the main functions Operating System?

    The main functions of an OS are: Process Management Memory Management Input/ Output Management Storage/ File system management

  17. 17.What are the main functions of a Kernel?

    The main functions of a Kernel are: - Process management - Device management - Memory management - Interrupt handling - I/O communication - File system management

  18. 18 . What is a semaphore?

    A semaphore is a hardware or a software tag variable whose value indicates the status of a common resource. - Its purpose is to lock the common resource being used. -A process which needs the resource will check the semaphore to determine the status of the resource followed by the decision for proceeding. - In multitasking operating systems, the activities are synchronized by using the semaphore techniques.

  19. 19.Describe the objective of multiprogramming.

    The main objective of multiprogramming is to have a process running at all times. With this design, CPU utilization is said to be maximized.

  20. 20 . What is time-sharing system?

    In a Time-sharing system, the CPU executes multiple jobs by switching among them, also known as multitasking. This process happens so fast that users can interact with each program while it is running.

  21. 21 . Give some benefits of multithreaded programming.

    - there is increased responsiveness to the user – resource sharing within the process – economy – utilization of multiprocessing architecture

  22. 22 . Define schedulers.

    A process migrates between the various scheduling queues throughout its life time. The OS must select processes from these queues in some fashion. This selection process is carried out by a scheduler

  23. 23 . State the advantage of multiprocessor system.

     Increased throughput.  Economy of scale.  Increased reliability.

  24. 24 . What is the use of cache memory?

    The data most recently accessed by the process populate the cache for the processor. As a result, successive memory accesses by the process are often satisfied in cache memory.

  25. 25 . What is multicore processor?

    Hardware has been to place multiple processor cores on the same physical chip, resulting in a multicore processor. Each core maintains its architectural state and thus appears to the operating system to be a separate physical processor.

  26. 26 . Differentiate tightly coupled systems and loosely coupled systems?

  27. 27 . Components of Computer System .

  28. 28 . Operating System Structure.

  29. 29 . Mention the advantages in using multiprogramming systems.

    Multiprogramming makes efficient use of the CPU by overlapping the demands for the CPU and its I/O devices from various users.  It attempts to increase CPU utilization by always having something for the CPU to execute.  Increased throughput.  Lower response time.

  30. 30 . What is graceful degradation?

    In multiprocessor systems, failure of one processor will not halt the system, but only slow it down by sharing the work of failure system by other systems. This ability to continue providing service is proportional to the surviving hardware is called graceful degradation.

  31. 31 . What are the different scheduling algorithms ?

    First-Come, First-Served (FCFS) Scheduling. Shortest-Job-Next (SJN) Scheduling. Priority Scheduling. Shortest Remaining Time. Round Robin(RR) Scheduling. Multiple-Level Queues Scheduling.

  32. 32 . What are the necessary conditions for deadlock?

    Mutual Exclusion: There is a resource that cannot be shared. Hold and Wait: A process is holding at least one resource and waiting for another resource which is with some other process. No Preemption: The operating system is not allowed to take a resource back from a process until process gives it back. Circular Wait: A set of processes are waiting for each other in circular form.

  33. 33 . What is Belady’s Anomaly?

    Bélády’s anomaly is an anomaly with some page replacement policies where increasing the number of page frames results in an increase in the number of page faults. It occurs with First in First Out page replacement is used.

  34. 34 . What is Preemptive Scheduling?

    A Scheduling discipline is Pre-emptive if the CPU can be taken away before the process completes

  35. 35 . What is Non - Preemptive Scheduling?

    A Scheduling discipline is non preemptive if once a process has been given the CPU, the CPU cannot be taken away from the process