Ok here is a quick summary of the lettered xbox partitions and what you can expect to find in them.
C: - on a retail xbox, contains the xbox's retail audio and fonts, the microsoft dashboard, the xbox live dashboard and all settings information, among other things. Many recent installers can leave this partition untouched during the install, this makes restoring manually alot easier.
D: - the xbox's DVD-ROM disk drive. When there is no disk, it will be empty. Put a disk it and it will display the contents.
E: - on a retail xbox this will only be the TDATA and UDATA folders. These are used primarily for gamesaves, but also contain saved soundtracks, game updates and downloaded content. On a modded xbox (with a retail harddisk), this is your primary saveplace. Here you will find (when using recent installer packages): Emulators and Apps folders, Backups, Cache, Your Non-Retail Dashboard, a Games Folder and depending on what programs and emulators you use and how they are configured, there may be a 'videos' folder, or 'saves, or 'screendumps'. This partiti
F: - this partition was created when microsoft changed their drive manufacturers, but didnt want the extra space to be noticable - making consumers think they have to 'upgrade', making older xboxes less valuable then new etc. If you have a Western Digittal Harddrive, it will be 8gb; if you have a Seagate, chances are its a 10gb so you have untapped space! To use this space you will need to format it (see tutorial
here). Many Dashboards are configured to use apps in both e:\apps and f:\apps as default, same applies for games in e:\games and f:\games.
G: - this drive letter will only be used if you have upgraded your xbox's hd and it is over 127GB. For more info on upgrading your hd - see tutorial
hereH: I: J: K: L: M: N: O: - these drive letters have confused many people. They are the xbox memory cards! H: is for controller 1 slot 1, I: is for controller 1 slot 2, J: is for controller 2 slot 1 etc. etc.
X: Y: and Z: - I have grouped these drives as they all share the same purpose - caching. Temporary files will be saved here during gameplay, either for faster loading times or smoother in game play. These are
temporary and are frequently deleted. Clearing these drives is fine and occasionally usefull: if we tell you to do it its ok (generally).
There's a chance this may already have been posted here but i couldnt find it. Any comments, things ive missed, questions, complaints leave them below and ill get really upset and annoyed at you - have i missed any drives? Not that i can think of but hey.