Browse Prior Art Database

Table-Driven Data Recovery Procedures

IP.com Disclosure Number: IPCOM000101801D
Original Publication Date: 1990-Sep-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Lautenschlager, DA: AUTHOR

Abstract

Disclosed is a method of using tables to provide greater flexibility in programming Data Recovery Procedures for disk drives.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 93% of the total text.

Table-Driven Data Recovery Procedures

       Disclosed is a method of using tables to provide greater
flexibility in programming Data Recovery Procedures for disk drives.

      This method consists of two tables; the first provides a
pointer into the second, which details the procedures to be
undertaken during each step of data recovery.

      Table 1 (see Fig. 1) is an example of the first table. It is
a one-byte-wide table.  The pointer into this table (Ptr-1) is the
step number of Y data recovery steps, or in the case where the
procedures are a series of Y steps repeated X number of times, it is
mod Y (data recovery step).  The byte pointed to in Table 1 by Ptr-1,
in turn, is a pointer into the second table.

      Table 2 (see Fig. 2) is an example of the second table used in
this method.  The pointer into this table (Ptr-2) is the byte pointed
to in Table 1.  The table width depends on the number and type of
actions to be performed for this step of data recovery.  In this
example, it is four bytes wide.

      Possible byte values are:
Bytes 1 & 2    Amount of track offset to be applied on this step.
Byte  3        Indicates how many bits of Error Correction to use.
Byte  4        Indicates how much to alter head sensitivity.

      This method builds great flexibility into the code two ways:
1.  The order in which procedures are done can be changed by altering
Table 1 which points to the actions for that step.
2.  T...