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RAIDBY : Tanvi HardeniyaConclusionThis paper make two separate points. 1)The advantage of building I/O system for personal computer disk. 2) The advantage of 5 different disk array organization.

Conclusion RAID offers a cost effective option to meet the challenge of exponential growth in the processer and memory.Size reduction of personal computer disk is the key to success of disk array. since the number of I/O per sec for an inexpensive disk is within a factor of two of large disk.RAID offers an attractive alternative to SLED in terms of performance , reliability , power consumption .The measure challenge is reliability.We must use extra disk containing redundant information to overcome from disk fails.The highest performance of disk come from level1 and level 5.For transaction processing using less then 50% of the storage capacity use level 1.For transaction processing using more then 50% of the storage capacity or for supercomputer application use level 5.

We see the different levels of RAID 1) Mirrored disk: Duplicating all disk can double the cost. 2)Hamming code for ECC : Uses ECC to monitor correctness of information on disk 3)Single check disk per group: Few less disk 4)Independent R/W: Perform parallelism 5)No single check disk : It distribute the data and check information across the disk hence multiple writes per group.

Issues on RAIDwhat is the impact of RAID on Latency?What is the impact of MTTF on individual disk?What is the real lifetime of RAID vs calculated MTTF?How is synchronized disk affect level 4 and 5 RAID performance?How does slowdown s actually behave?How does defective sector affect RAID?How should 100 to 1000 disk constructed and physically connected to the processer?What is the impact of cabling on cost, performance , reliability ?Where should be RAID connected to CPU so as not to limit performance?

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