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RAID Controllers
Raid Controllers






The world's earliest industrial RAID prototype!

The RAID and I/O Systems project, part of the Storage Systems and Servers department, has made many fundamental contributions in the areas of I/O (storage) subsystems and RAID technology. These contributions have resulted in significant advancements to the architecture, algorithms and practical implementation of I/O and RAID technology in the industry; they have had an impact on every significant IBM RAID product.

Over 7 years of research, we have published in excess of 20 RAID papers and collectively hold 20 patents on RAID technology. Our project has invented many ideas which are widely referenced and cited by the research community; for example:

  • distributed sparing
  • Cached RAIDs
  • fault tolerant RAIDs
  • floating parity
  • parity sparing
  • 2-D parity
  • opportunistic rebuild
  • EVENODD codes
  • hierarchical RAIDs

These algorithms improve the performance and availability of RAID controllers significantly.

Our group built the first RAID prototype in IBM and the industry (contemporaneous with the Berkeley RAID prototype). This prototype, called Hagar, was the first to use ideas like non-volatile caching and fault-tolerant design, now routinely used in RAID designs.

We have made significant contributions to products such as the IBM RAMAC and the IBM 9337 RAID products, which have been commercial successes. We have also done significant research, invention and analysis of a newer form of RAID which includes compression called log-structured RAID.

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