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Reconstruction Mechanism for Address Translation Table used in the Solid State File

IP.com Disclosure Number: IPCOM000117246D
Original Publication Date: 1996-Jan-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 77K

Publishing Venue

IBM

Related People

Niijima, H: AUTHOR

Abstract

Disclosed is a method that reduces the time taken to reconstruct the Address Translation Table (ATT) used in the Solid State File (SSF).

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Reconstruction Mechanism for Address Translation Table used in the
Solid State File

      Disclosed is a method that reduces the time taken to
reconstruct the Address Translation Table (ATT) used in the Solid
State File (SSF).

      Each Cluster Information Sector (CIS) contains one or more
reverse pointer sets (RPSs).  It also contains corresponding number
of cluster indexes (IDs), each of which indicates the cluster of RPSs
contained in the CIS.  The SSF controller reconstructs the ATT by
referring solely to RPSs, insofar as this is possible.  If RPSs, for
some clusters are missing, it reconstructs the ATT by scanning all
reserve pointers (RPs) in the clusters.

      The Figure shows an example in which two RPSs exist in each
CIS.  The number of RPSs can be increased or decreased as required.
Obviously, the more RPSs there are in each CIS, the fewer RPSs will
be missing.

      Suppose that four clusters exist in an SSF and that the cluster
sequence numbers (CSN) are in order, as shown in the Figure.  The
first sector of each cluster is the CIS in which one or more RPSs and
their ID are written.  The ID consists of the cluster physical number
and CSN, and is therefore denoted by
      ID = i(cluster physical number, CSN)

      Consequently, if a CSN value of 16 is assigned to a cluster
whose cluster physical number is 2, its ID is written as
      i(2,16)

      An RPS is an aggregation of all the RPs contained in each
physical cluster and holds all the sector information (e.g., the
attribute of each sector) needed to reconstruct the ATT.  That is,
the ATT is constructed in such a way that all the attributive
information needed to reconstruct it can be obtained by reading out
the RPSs.  For instance, provided that an RPS holding a valid ID =
i(2,x) is found, the RPs in the cluster whose cluster number is 2
need not be scanned when the ATT is reconstructed.

      Whether or not an existing RPS i...