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Operating Systems CPSC 304
Homework on Device Management
Earl Rodd erodd@malone.edu Extension 8546 www.malone.edu/erodd

    Name: ______________________________________

  1. Mark devices as (S)hared, (D)edicated or (V)irtual.

    1. ___ Keyboard in Windows (from a user's point of view).

    2. ___ RAID disk array.

    3. ___ Scanner

    4. ___ Memory Stick

    5. ___ Laser printer

  2. Write the level of RAID (0, 1, 3, 5) most appropriate for these cases. If two or more levels are appropriate, use the lowest level.

    1. ___ Need only the capacity of one disk, but need full availability of data even if a disk fails.

    2. ___ High availability is not a concern, but speed, especially of intensive writing is a priority.

    3. ___ The application requires 3 disks capacity of data and needs recovery if any disk fails. The data is created monthly. The requirement is for speed during the read operations taking place online every day.

    4. ___ The application requires 5 disks capacity of data and needs recovery if any disk fails. There is intensive read and write activity online. Speed should not be sacrificed to recoverability.

  3. When a Java program uses the RandomAccessFile.seek() method, will DM definitely do a hardware seek? ____

    Why or why not? _____________________________________-

  4. With RAID-0, using 40 Gig disks, how many disks must the array have to store 120 Gig of data? ___________

  5. With RAID-1, using 40 Gig disks, how many disks must the array have to store 120 Gig of data? ___________

  6. With RAID-3, using 40 Gig disks, how many disks must the array have to store 120 Gig of data? ___________

  7. We have a server with multiple disks. There is one 500,000 byte file which is accessed VERY heavily. What strategy can you think of to absolutely minimize the seek time to this file?

    __________________________________________________________________

  8. If a disk rotates 5000 RPM (rotations per minute), what is the average rotational delay? _______________________