hi guys

i was wondering if someone could tell me how you work out these questions! id really appreciate help on these as im fine with the rest of the book, just cant get these!!

1. An application uses ten 9 GB devices. A full volume local replica of the app is required every 6 hours. Each replica will be kept for 24 hours, how many replica devices are required?

2.  A disk has cylinder Head Sector (CHS) valued of 1000, 4 and 25. What address range will be used for the logical block address (LBA) Values for this disk?

3. You have five disks in a raid 0 set and have assigned a striped depth of 128 blocks (64 kb) . What is the stripe size (KB)?

4 . An application used ten 9 GB devices. A pointer based replica of the application is required every 4 hours. Each replica will be kept for 24 hours. The data changes by 10% every 4 hours. How many replica devices are required ?

please??