The RAID and I/O Systems project, part of the Storage Systems function,
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.
During 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 that 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
that includes compression called log-structured RAID.
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