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Buffer Management System With Binary Tree Organization of Active Buffers for Fast Search and With Queue for Buffer Reclaim

IP.com Disclosure Number: IPCOM000047395D
Original Publication Date: 1983-Nov-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Maccabee, MM: AUTHOR

Abstract

A limited number of buffer spaces are available in main memory for holding blocks of data that each contain one or more records of several data sets. Each of these records has information and pointers that form a conventional search tree. Blocks that contain the root of a search tree and a few blocks that form a subtree of records that are most actively being processed are kept in the main store buffers. These buffers are linked in a binary tree that permits fast searching for the records in these buffers. In addition, the buffers are linked in a chain of least recent use. For reclaiming buffer space, the root buffers of each data set are linked to an index control block (ICB) and the ICBs are connected in a queue that is headed by a queue control block (QCB).

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Buffer Management System With Binary Tree Organization of Active Buffers for Fast Search and With Queue for Buffer Reclaim

A limited number of buffer spaces are available in main memory for holding blocks of data that each contain one or more records of several data sets. Each of these records has information and pointers that form a conventional search tree. Blocks that contain the root of a search tree and a few blocks that form a subtree of records that are most actively being processed are kept in the main store buffers. These buffers are linked in a binary tree that permits fast searching for the records in these buffers. In addition, the buffers are linked in a chain of least recent use. For reclaiming buffer space, the root buffers of each data set are linked to an index control block (ICB) and the ICBs are connected in a queue that is headed by a queue control block (QCB). When a block is accessed, the ICB of its data set is moved to the head of the queue, so that the queue lists the data sets in the order of recent activity. When space is needed in main memory for a new block, the buffer to be reclaimed from memory is selected from the data set of the last ICB of the queue. Thus, this buffer management system allocates buffers to the most active records of all data sets and thereby minimizes the number of I/O operations that are needed. Background A data set is a collection of related records which are held, for example, on a magnetic disk in physical un...