Hi. Im asking questions on behalf of a friend in another state, so I cant visually verify anything discussed here. I guess my question is: What is the largest possible HDD that a 15 1.0/1.25GHz G4 Powerbook can support? Background: Years ago, my friend received a used 15 PB G4. (We think it's one of the 15" Macs listed here: <http://support.apple.com/kb/sp91>) I dont think she has the start-up discs, and the family friend who sold it to her (long since gone) replaced the stock HDD and loaded it with OS X 10.5.8, which she says is what its running now. But 10.5.8 on her G4 doesnt show the size of the current/replacement HDD. (Both System Report and doing Command + I on the hard drive turn up some message that doesnt give a figure in GBs.) She needs to make a complete back-up of her Mac before it dies (she feels soon), but shes short on money and cant afford to overspend on an external HDD thats too big for this one job. (Its why shes still using a computer this old, that she got as a used gift to begin with.) How big could the replacement drive in her Mac be?