But recently I found Fujitsu has RAID-4 storage server(http://storage-system.fujitsu.com/jp/term/raid/07.html)
# I'm a kind of Fujuitsu guy.
RAID-5 has all the advantages of RAID-4,plus its know-how and merits and flaws are all well-knownn(compared to rare RAID-4).
You may be able to consult with Google for any time for any trouble.(Correctness of answer is not guaranteed,but you can try)
Does RAID-4 have any advantages over RAID-5?
Any Comments and Suggents(especially from RAID-guru) are welcomed