ERODD HOME

Operating Systems CPSC 304
Homework on Chapters 11-12
Earl Rodd erodd@malone.edu Extension 8546 www.malone.edu/erodd

Name: ______________________________________

  1. With Intel architecture, to write 4000 bytes to a disk, what is the minimum number of OUT instructions required? ________

  2. With zSeries architecture, to write 4000 bytes to a disk, what is the minimum number of SSCH instructions required? _________

  3. What is the main advantage of using channels?

    __________________________________________________

  4. How large is a disk with 20000 cylinders with 2 tracks/cylinder with 1000 sectors of 512 bytes on each track?

    ______________________________________________________

  5. Because my system uses SPOOLing, if my physical printer is turned off when I tell my browser to print a page, what happens?

    ______________________________________________________

    ______________________________________________________

  6. Your personal computer spends a lot of time with the CPU in "wait state". What causes it to exit wait state?

    ______________________________________________

  7. What would happen if the CPU was placed into a wait state while all interrupts were masked?

    _______________________________________________________

  8. Which of these events causes an interrupt? Mark the ones which do.

    1. ___ Execution of a valid branch instruction (if statement)

    2. ___ Disk controller finishes a seek operation to move the disk arm to a certain cylinder.

    3. ___ Operating system setting the time for 100 ms.

    4. ___ The timer counting down to zero.

    5. ___ Instruction executed whose operation code is not a valid instruction.

    6. ___ Program does a "call" via a branch to a library function.

    7. ___ Program does an SVC (or Intel INT) instruction.

  9. When a hardware interrupt occurs, it is critical that a certain piece of code in the operating system is executed. Explain how the hardware knows which piece of code to run.

    _________________________________________________

    _________________________________________________

    _________________________________________________

  10. What is the name of the hardware which has the address of the instruction currently executing?

    INTEL _______

    Mainframe _________