RAID 5 Total storage

[Keith130]

Im confused about the RAID 5 equasion thingy on how to get the total size of the array. Its (n-1)*smallest HDD isnt it? So if I get four 80GB disks what would the total size be?

EDIT : What does "(n-1)*smallest HDD" actually mean?

[Soralis]

n is the number of drives, so if you had 4 80GB drives, the space you'd have avalible for use would be that of 3 80GB drives, or 240GB.

If you had 3 80GB drives, you'd get the space of 2, or 160GB, if you had 6 80GB drives, you'd get the space of 5, or 400GB. That's what the (n-1) means.