In Windows, each drive letter is its own seperate little world. c:\ gets you files under partition 1, d:\ gets you files under partition 2, etc.

In UNIX, all files and partitions are accessed through the same directory tree. The root partition is attached first, at /, and other partitions can be optionally attached to any directories inside /, even ones inside other partitions.

On one of my systems:

Code:

$ df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sdc3            1008M  298M  660M  32% /
udev                   10M  340K  9.7M   4% /dev
/dev/sdc5              20G   12G  7.2G  62% /home
/dev/sdc6             9.9G  4.6G  4.9G  49% /usr
/dev/sdc7             5.6G  735M  4.6G  14% /var
/dev/sdc8             116G  5.0G  111G   5% /var/lib/mysql
shm                   948M     0  948M   0% /dev/shm
/dev/md1p8            394G  301G   74G  81% /opt
/dev/md1p9            1.4T  848G  552G  61% /opt/disk-images
/dev/sdc1              63M   28M   32M  47% /boot

So the root directory exists on the partition /dev/sdc3. If you created a file /randomname, it'd go into sdc3.

"udev" and "shm" are special filesystems handled by the kernel, you can ignore them for the moment.

Anything under /home/ goes into sdc5, so all user directories reside on that partition.

Our mysql database used to reside inside under the /var/ partition, in /var/lib/mysql, but it outgrew it. I had to give /var/lib/mysql its own partition so mysql would have more room.

And so on, and so forth.