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Parallel Library Paths Result in Fault Tolerance

IP.com Disclosure Number: IPCOM000109167D
Original Publication Date: 1992-Aug-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 3 page(s) / 81K

Publishing Venue

IBM

Related People

Krebs, SA: AUTHOR [+3]

Abstract

Disclosed is a method of creating fault tolerance in computer-based library systems by utilizing parallel library paths.

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This is the abbreviated version, containing approximately 62% of the total text.

Parallel Library Paths Result in Fault Tolerance

       Disclosed is a method of creating fault tolerance in
computer-based library systems by utilizing parallel library paths.

      By convention, library systems have had a sequential structure.
Movement of items within the libraries follows this sequential path.
If defective items are deposited into the library, often the only
recourse is to have the defect corrected before normal development
may resume.  This is due to the sequential nature of the library, and
the fact that all users of the library interact with the same library
levels (an indivisible library repository).  In situations like this,
it is not uncommon to have the product being developed using the
library, "broken", and the development team scrambling to "get it
fixed".  By adding parallel levels to the library, the frequency and
impact of this type of problem can be greatly reduced.  This is due
to the fact that there are multiple instances of the library level,
any one of which is a candidate for selection as the current product,
while the rest are worked on further.  An example should make this
very clear.

      The LAN Library Management System is a library system used by
many groups within IBM.  Its structure is shown in Fig. 1.  Each
level is reached sequentially from the one preceding it.  Breakage in
any level may cause a situation in which movement within the library
must be stopped to prevent the breakage from affecting the...