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Browse Prior Art Database

Fast DASD Processing Method to Write Command

IP.com Disclosure Number: IPCOM000109297D
Original Publication Date: 1992-Aug-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 2 page(s) / 68K

Publishing Venue

IBM

Related People

Asano, H: AUTHOR [+2]

Abstract

This article discloses hard disk drive (HDD) sector buffer control method using non-volatile RAM. Write command completes operation after data transferred to disk. This invention allows write command completion after data transferred from host to sector buffer which improves write command performance.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Fast DASD Processing Method to Write Command

       This article discloses hard disk drive (HDD) sector
buffer control method using non-volatile RAM.  Write command
completes operation after data transferred to disk.  This invention
allows write command completion after data transferred from host to
sector buffer which improves write command performance.

      Fig. 1 shows control flow of the new method in comparison with
prior art.  Fig. 2 shows a block diagram of HDD configuration of the
invention.  If a non-volatile RAM is used in sector buffer, the
configuration is the same.  A status bit which shows completion of
the sequence of write operation to sector buffer, but not to disk, is
prepared.  This bit is set after write operation is completed to
sector buffer.  HDD response to host is that write operation
completed though data write to disk is still going.

      After completion of writing data to disk, this bit is reset.
All the related data such as Head/Cylinder/sector address are also
stored in non-volatile memory.  If powered-off while writing data to
disk but host transfer completed, all the data are stored in the
non-volatile memory.

      When powered-on, HDD checks status bit in non-volatile memory.
If this bit is on, recovery routine will start to re-send data in the
sector buffer to disk using parameters also stored in non-volatile
memory.  After completion of this recovery routine, status bit is
reset.