13. (a) What must the code distance be to detect five errors? (b) What must the code distance be to correct five errors?

15. (a) How many data bits are required to store one of the decimal digits 0 through 9? (b) How many parity bits are required to correct a single error?

16. A set of eight data bits is transmitted with the single-error correction code of Figure 9.25. For each of the received bit patterns below, state whether an error occured. If it did, correct the error.

(b) 1 1 0 1 0 0 1 1 0 0 1 0

(d) 1 0 1 1 0 0 1 0 0 1 0 0

18. (a) Figure 9.28 shows the RAID level 01 and RAID level 10 systems with eight physical disks. Draw the equivalent systems for level 01 and level 10 with four physical disks.

(c) to determine the probability that the RAID disk fails for levels 01 and 10. Which RAID system is more reliable?

15. Draw the nonabbreviated logic diagram for the following Boolean expressions. You may use XOR gates.

(e) ab + ab + ab

(f) ((ab b) + ab)

(g) (abc + a)b

(m) (a b) c + abc

(o) (ab + bc + cd)