Browse Prior Art Database

Leaf Disk Data Management

IP.com Disclosure Number: IPCOM000075211D
Original Publication Date: 1971-Aug-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Boyson, R: AUTHOR [+3]

Abstract

A method of disk file data management is provided for creating or maintaining a consecutive file of data in an indexed random and update mode, without an index being part of the consecutive file.

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Leaf Disk Data Management

A method of disk file data management is provided for creating or maintaining a consecutive file of data in an indexed random and update mode, without an index being part of the consecutive file.

Data management consists of four parts: (1) ALLOCATION (2) OPEN (3) LEAF/WORK FILE DATA MANAGEMENT (4) CLOSE.

File allocation, Fig. 1, finds the two largest contiguous disk work areas present on disk files on line. The largest work area is halved and compared to the next-to-largest area. If the comparison is high or equal, the LEAF and WORK areas reside on the same drive and records will be written in a split sector format,
i.e., the disk work area will look as follows:

(Image Omitted)

If the comparison is low, the WORK and LEAF areas occupy contiguous sectors on different drives. In all instances, the WORK and LEAF areas are assigned the same number of sectors.

File OPEN, Fig. 2, assigns the initial TAG if performing a creation run. If the run is maintenance, the input consecutive file is moved to the WORK file, a TAG being assigned to each record. The format of the WORK file following OPEN appears as follows:

(Image Omitted)

The TAGS are generated in ascending order, and remain in that fashion throughout data management processing.

The data management consisting of Get and Put Logic, Figs. 3 and 4, is performed in the two work areas named WORK and LEAF, respectively. WORK is the current work area and LEAF is the work area records are leafed to...