geogeo,
The commands "df" and "du" will help you get started collecting information about your file systems (e.g. layout and usage). Reviewing the man pages for these commands (e.g. "man df") should get you off on the right foot.
Obtaining information about physical disks tends to be specific to your hardware configuration, the version of UNIX you are running, and if a logical volume manager (e.g. Veritas) is being used to manage the disks.
Posting your operating system should get you more detailed responses.
Hope this helps!
Biker
Systems/Network Administrator
LiveFire Labs - Hands-On Technical e-Learning
www.LiveFireLabs.com