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Random Access Disk Array with Cached Drive Unit

IP.com Disclosure Number: IPCOM000115639D
Original Publication Date: 1995-Jun-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 63K

Publishing Venue

IBM

Related People

Cheung, WL: AUTHOR [+3]

Abstract

Volumetric density in random access disk array structure is limited by imposing the same performance requirement for all the spindles in the system. This can be increased substantially by apportionment of capacities across different spindles with different performances in a new array structure.

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Random Access Disk Array with Cached Drive Unit

      Volumetric density in random access disk array structure is
limited by imposing the same performance requirement for all the
spindles in the system.  This can be increased substantially by
apportionment of capacities across different spindles with different
performances in a new array structure.

      In a drive, for example, it is likely that the customer does
not use a major portion of the information stored in the drive for a
substantial period of time but still desires to have all the
information residing on a drive available to him at all times.
Similarly, in a disk array string, it is not an optimum strategy to
require all the drive in the string to have the same performance
characteristics.  It is observed empirically that a substantial
portion of a drive remains unused by most customers and the
traditional strategy of spinning all the drives in the string at the
same rate, or designing for equal performance is not optimum.  This
being the case, it is desirable to apportion the system into 2 (or
more) sections with one section having cached spindle units which are
designed for high performance having fast seek time, fast spindle
rotation, and high data transfer rate.  The new scheme allows the
array to increase the storage capacity and lower the overall drive
cost since the lower performance drive sections are designed to
operate at a higher linear and track density using yet less expensive
mechanical...