Browse Prior Art Database

Dual Surface Recording Architecture for Hard Disk Drive

IP.com Disclosure Number: IPCOM000122839D
Original Publication Date: 1998-Jan-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Ono, H: AUTHOR [+3]

Abstract

Disclosed is a system architecture for a hard disk drive to improve the data access performance while reducing the averaged latency of the disk revolution and the reliability by storing a set of data at two different surfaces. Refer to the Figure.

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Dual Surface Recording Architecture for Hard Disk Drive

      Disclosed is a system architecture for a hard disk drive to
improve the data access performance while reducing the averaged
latency of the disk revolution and the reliability by storing a set
of data at two different surfaces.  Refer to the Figure.

      The data sites are located on the same cylinder, but at 180
degrees to the opposite side of each other.  A set of data is first
written on one site which is reached with less latency than the
other.  The mirror site is updated later when the system operation is
not busy.  The data matching status is managed on a nonvolatile
memory in order not to lose the status under an unexpected system
down.  In retrieving the data, the near site is accessed if the data
matches on both sites.  In the other case, the newer data site is
accessed after waiting for the latency time.  Therefore, the averaged
latency can be shortened by about half in both cases of read and
write operations.  Consequently, the data reliability improves since
it is not influenced by single site hard errors.

There are two ways to manage the data matching status:

      The first method is:  a set of two bit flags which identify
each Logical Block Address (LBA) status.  One bit shows data
match/unmatch status.  And the other shows odd/even surface which
stores the latest data.  This method uses much memory but gives best
performance to refer the status.  The capacity of memory...