1. RAID CS147 Dr. Sin-Min Lee By Kenneth Chen

2. History Norman Ken Ouchi at IBM was awarded U.S. Patent 4,092,732 titled "System for recovering data stored in failed memory unit" in 1978 In 1987, RAID levels 1 through 5 were formally defined by David A. Patterson, Garth A. Gibson and Randy H. Katz in the paper, "A Case for Redundant Arrays of Inexpensive Disks (RAID)"

3. About RAID Early disk drives were costly and bulky They required strict environmental control Solution: RAID -- It stands for “Redundant Array of Independent Disks Idea: Link up a bunch of small, inexpensive disk. Also often referred to as JBOD (just a bunch of disks) Many different RAID method exists

4. RAID LEVEL 0 RAID 0 implements data stripping Pro: Least cost, very fast on read and write Con: Not reliable, no-fault tolerance

5. RAID 1 RAID 1 implements data mirroring Pro: Excellent Protection against crashing Con: Slow on write, costly and inefficient

6. RAID 2 RAID 2 implements bit stripping with ECC Pro: Good performance on both read and write. Good protection. Cheaper than RAID 1 Con: Hamming code generation is slow, still expensive, no commercial use

7. RAID 3 RAID 3 implements bit stripping with parity disk Pro: Very good performance on read, write. Good protection. Efficient. Con: Complicated controller design.

8. RAID 4 RAID 4 implements data stripping with parity drive. Pro: fast on read. Good protection Con: VERY slow write speed. Difficult data rebuild. Complex design. Not used in real life

9. RAID 5 RAID 5 implements data stripping with distributed parity Pro: Fastest read speed, decent write speed. Good protection. Cost effective = commercial success Con: Most complex design. Difficult to rebuilt data.

10. RAID 6 RAID 6 implements data stripping with dual error protection Pro: Excellent protection, can sustain multiple hits. Con: Complex to implement.

11. RAID 10 RAID 10 = 1 + 0 implements data stripping with mirror drive. Pro: Excellent protection. Good read and write speed compare to other. Con: Very expensive.

12. RAID DP RAID DP = Double Parity implements data stripping with dual parity disks. Pro: Excellent protection. Reasonable cost. Con: Performance not as good as RAID 5.

13. More on RAID Textbook page 364-376 http://www.acnc.com/raid.html http://en.wikipedia.org/wiki/Redundant_arr ay_of_independent_disks

14. THANK YOU!!!! And sorry for the boring presentation -_-