Computer Science 4630
Summer 2001
Practice questions for quiz 5

  1. A distributed file system exhibits location transparency if

    1. The name of a file indicates exactly where the file can be found.
    2. The name of a file does not indicate where the file can be found.
    3. The name of a file does not need to be changed when the location of the file changes.
    4. The name of a file is not adequate for finding the file.

  2. A file server provides stateless service if

    1. The files that it provides are not stored physically on that server.
    2. The files that it provides are stored physically on that server.
    3. The server keeps track of information about open files on client machines
    4. The server does not keep track of information about open files on client machines.

  3. Local caching of files is common in distributed file systems, but it has the disadvantage that

    1. Temporary inconsistencies among views of a file by different machines can result.
    2. The file system is likely to be corrupted when a computer crashes.
    3. A much higher amount of network traffic results.
    4. Caching makes file migration impossible.

  4. Suppose that somebody replaces the system encryption executable program by one that encrypts, but that also mails a copy of the cleartext of the document to himself. The modified program is called a

    1. virus
    2. worm
    3. Trojan horse
    4. trap door

  5. If a malicious process is granted temporary administrator-level access to a system,

    1. the threat is over as soon as the process is killed.
    2. the threat is over after the operating system is rebooted.
    3. the thread is over after rebooting the machine and replacing files that show a virus infection.
    4. the threat is often permanent until the entire disk is wiped clean.

  6. The access matrix approach to protection has the difficulty that

    1. the matrix, if stored directly, is large and can be clumsy to manage.
    2. it is not capable of expressing complex protection requirements.
    3. deciding whether a process has access to a resource is undecidable.
    4. there is no way to express who has rights to change the access matrix itself.