The Linux/UNIX file system is logically organized into directories having specific purposes. For example, the home directory contains one login directory or workspace for every single user of the system. You see that in figure 1 the home directory has a subdirectory for some of the teachers in this program. It will also most likely contain a directory for each of your working groups. But you will notice also, that there are quite a lot of other directories in the file system. For instance, the directory / is the root or lowest directory of the file system. The home directory, and others lie above it, forming the Linux directory tree. home is but a branch of this tree.
Other important directories just above root are dev, spool, and usr. dev contains the files for all the devices attached to the computer, like for instance, drivers for printers, the monitor, the keyboard, mouse, and so on. spool contains files which are used to keep traffic to a certain device or program in order, for example, for mail, or printing. Finally, usr contains most of the executable user software (in particular, that software and utilities shared by all users of a system), such as UNIX utilities, math programs, word processors, mail utilities, and so on.
A directory not shown in figure 2 is the var directory. While containing some other utilities, this directory most importantly contains the system log, user mail files, some temporary files, and so on.
Finally, to locate files, you use a path, consisting of nested directories, from the more general to more specific. This is literally a path through the directory tree. For example, a file located in rawdingc's directory would have path /home/rawdingc/file.ext.