Louis Reasoner has just read an advertisement for a RAID controller that provides a choice of two configurations. According to the advertisement, the first configuration is exactly the RAID 4 system described in Section 8.4.1. The advertisement goes on to say that the configuration called RAID 5 has just one difference: in an N-disk configuration, the parity block, rather than being written on disk N, is written on the disk number (1 + sector_address modulo N). Thus, for example, in a five-disk system, the parity block for sector 18 would be on disk 4 (because 1 + (18 modulo 5) = 4), while the parity block for sector 19 would be on disk 5 (because 1 + (19 modulo 5) = 5). Louis is hoping you can help him understand why this idea might be a good one. 8.10a. RAID 5 has the advantage over RAID 4 that
A. It tolerates single-drive failures..
B. Read performance in the absence of errors is enhanced.
C. Write performance in the absence of errors is enhanced.
D. Locating data on the drives is easier.
E. Allocating space on the drives is easier.
F. It requires less disk space.
G. There's no real advantage, its just another advertising gimmick.