Browse Prior Art Database

Hard Disk Drive Backup System

IP.com Disclosure Number: IPCOM000122488D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Asano, H: AUTHOR [+2]

Abstract

Disclosed is a technique for the concurrent operation of a HDD (Hard Disk Drive) backup system. This technique enables a host to store data while the HDD data recovery routine is being executed.

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

Hard Disk Drive Backup System

      Disclosed is a technique for the concurrent operation of
a HDD (Hard Disk Drive) backup system. This technique enables a host
to store data while the HDD data recovery routine is being executed.

      The characteristics of this technique are:
- to have a separate bus and RAM for a primary HDD and for a
secondary HDD, and
- to have a bidirectional buffer to connect the primary and the
secondary buses between the RAM and HDD.

      Fig. 1 shows the normal function.  A host 1 writes data in two
RAMs (RAM-P 2 and RAM-S 3) synchronously, and the written data in
RAM-P and in RAM-S are independently written to P-HDD 4 and S-HDD 5,
respectively.

      Fig. 2 shows an example of the recovery function. When S-HDD
data recovery routine is running, recovered data is passed from P-HDD
4 to S-HDD 5 through a bidirectional buffer 6. If the host writes
data during the recovery routine being run, the host writes data only
into RAM-P 2. RAM-P 2 data will be written to P-HDD 4 after the
recovery routine is completed. If this block is already recovered,
this data will be transfered to S-HDD also through the bidirectional
buffer.

      Thus the recovered data and latest data are saved independently
and simultaneously.