Operating Systems 2014F Final Exam Review

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The audio from the review session (held December 9, 2014) is now available.

Notes

Concepts

  • file sizes (logical versus blocks consumed)
  • mounting a fs
    • changes in filesystem hierarchy
    • concept of a "root" filesystem
    • privileges required
  • loopback mounts and files
    • /dev/loopX
  • holes in files
  • stat on files


Sample Questions

  • If a program "seek"'s on a zero length file to position 100,000 and then writes one byte, what would you expect the file's logical length to be? What about its physical size (space consumed on disk)?
  • You download a CD image (ISO 9660), but you only want one file that is on the CD. Note the file is encoded with the standard ISO filesystem (that your computer already knows how to process). One way to get that file would be to burn the CD and then read the file off of it. How could you get the file WITHOUT burning a CD? (Would doing this require the use of a block device?)
  • There are many restrictions on mounting filesystems (which users, what devices, etc). How could you fundamentally change the running of a system using an unrestricted mount?