I am a new user of Ubuntu. When I type df -h in terminal , it gives me list of all storage devices and space usage. In my system I get this.

Filesystem      Size  Used Avail Use% Mounted on
/cow            934M  173M  761M  19% /
udev            925M  4.0K  925M   1% /dev
tmpfs           374M  856K  373M   1% /run
/dev/sdb1       7.5G  2.8G  4.8G  37% /cdrom
/dev/loop0      1.5G  1.5G     0 100% /rofs
tmpfs           934M   16K  934M   1% /tmp
none            5.0M     0  5.0M   0% /run/lock
none            934M   76K  934M   1% /run/shm
/dev/sda        299G   74M  299G   1% /media/q

I understand that /dev/sda is my hard drive which is 320 gb(in gib it is 299 and hopefully that is what is being displayed) and /dev/sdb1 is pendrive of 8gb from which I am running the live cd.

My question is what are the other folders and what is the physical location of these folders if complete memory is taken by the device dev/sda?