The Filesystems window displays information about the machine's filesystems. The default display begins by showing a display of free space on filesystems on the machine. On the left is a graphical representation of the relative sizes of those filesystems, and on the right are details for each filesystem: its name, the percentage of free space on it, and whatever parameter you have selected to view: the allotted size, the used size, or the amount free on it. You can refine exactly how gtop displays these with the Preferences dialogue and with the View Menu.
Filesystems under UNIX can be a little daunting. There is a fuller explanation in the appendix to the GNOME users' guide. The display on the filesystems window will vary from machine to machine. It depends on what filesystems are actually mounted on your machine. For a fuller explanation of mounting, you may wish to look at the documentation for your system, or at the appendix in the GNOME Users' Guide. Most mounting is performed automatically when the machine boots up and depends on how the hard disk is partitioned.
The simplest - and most common - method is to have just a single filesystem mounted on your machine. This is generally called the root filesystem and denoted by a slash: /. If your hard drive is arranged as a root filesystem and swap space, and if you have no CDROM or floppy disk mounted at the moment, then as there is only one filesystem, the display on the left will be in one colour only with a single label for it on the right:
Some machines have more complicated layouts than this. They have separate parts of the overall filesystem partitioned into their own areas. This is good practice to stop an accident in one filesystem from affecting files in another. If there are several filesystems mounted on your machine, then each one will be represented by a different colour and the label for it on the right will be colour-coded appropriately. Again, swap space will not appear on this list.
It is also possible to mount some filesystems whilst the machine is running. A very common example is a CD-ROM or a floppy disk. These have filesystems on them. Another example is found on networked machines running NFS (network filesystem). If CD-ROMS, floppies, or remote filesystems are mounted, then they too will show up on the gtop display:
Solaris users should be aware that Solaris deals with swap slightly differently from most UNIX and UNIX-like systems. It has a special filesystem called tmpfs which holds both swap space and the /tmp directory. As more files are put into /tmp, the available swap space shrinks. The tmpfs filesystem does not show up on the filesystem display.
Several menu options can affect the display in the filesystems window. There is also a toolbar which is described in the Processes section of this document.
The File Menu provides the same options as the File Menu on the Processes Window. See there for the description.
The View Menu provides a choice of three options:
The Total Filesystem Size display shows filesystem sizes relative to how much space has been allotted (typically by partitioning) for each filesystem.
The Used Filesystem Size display shows filesystem sizes relative to which filesystems are the most full: a small but very full filesystem will take up more space in the graph than a large but empty one.
The Free Filesystem Size display shows filesystem sizes relative to which filesystems have the most space on them: a small but very full filesystem will take up less space in the graph than a large but empty one.
The Settings Menu gives access to the Preferences dialogue.
The Help Menu gives access to the 'About' dialogue box and gtop's credits.