CSCI 251 F04 Midterm Examination
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Instructions:
  - this is a closed book, closed notes, no electronic computeng
    device exam
  - you have 65 minutes to complete the exam
  - write all answers in the exam book provided
  - attempt all questions
  - state any assumptions
  - point values are given in square brackets; maximum is 100 points
  - all questions pertain to material covered in lectures and labs



Q1: [12] Your friend is finding his computer running too slow with the
    new applications he has recently installed. Under what
    circumstances would you recommend him to

    a) install a new CPU  b) increase RAM  c) install a bigger hard
    disk?


Q2: [20] Intermittent problems in network access using your Debian PC
    leads you to believe that your network card (NIC) is somehow
    defective. You replace the old NIC with a new one (a different
    make), to find out that the network is not accessible at all with
    the new NIC.

    What could be the possible cause(s) and how would you go about
    correcting it (them)?


Q3: [15] You used a set of three floppy disks to install Debian
    GNU/Linux on your PC in the lab. This included re-partitioning and
    re-formatting the hard disk thereby destroying any previous data
    on the hard drive. This also means that anybody who has physical
    access to your computer can come with the same set of disks and
    destroy all data on your computer.

    What measures should you take to prevent this from happenening?
    After implementing those measures, is your computer now fully
    protected? Why?


Q4: [15] You want to run an X window application which, however,
    consumes a large amount of computing resources. Running it on your
    PC which is running Debian GNU/Linux would slow down everything
    else you are doing. You know that the powerful server machine
    running Tru64 Unix on the same network has the same program
    installed on it.

    Briefly explain the steps you would take to enable an X connection
    across the machines so that the program started on the server
    machine could display its window(s) on your PC.



                                                 (Please turn over ...)




Q5: [18] Give a brief description of the directory hierarchy of a
    Debian system indicating what kind of files are stored in each
    branch of the directory tree. Why is it good to have a number of
    partitions for various directories than having a single partition
    holding all directories?  Why is it not a good idea to have a
    separate partition for /etc?


Q6: [20] Unlike TCP, the companion protocol in the Transport Layer UDP
    is a 'thin' protocol which basically just facilitates applications
    to use the unreliable IP packet delivery. Consequently, it has
    much lower overhead as compared to TCP and, hence, is more
    efficient.

    You notice that an application relying on UDP that works perfectly
    on a local network fails badly when used over a larger TCP/IP
    network. Explain this behaviour.