Improved disk file allocation and mapping system utilizing cylinder control blocks and file map having unbalanced tree structure
US4536837A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 25, 1982 |
| Grant date | Aug 20, 1985 |
| Priority date | — |
| Expiry date | May 25, 2002 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99956
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A disk file management system for use in a data processing system that includes at least one disk drive. The disk space is organized on the basis of logical cylinders, with each logical cylinder including a plurality of disk pages and a cylinder control block ("CCB"). Each entry in the CCB corresponds to a page in the CCB's cylinder. Depending on whether a page is allocated to a file or not, the corresponding CCB entry is a file map entry for a file to which the page is allocated or an entry in a free space map. For a given file, each file map entry includes up to two pointers so that the totality of page map entries for the file defines an unbalanced binary tree structure that consists of a sequence of balanced binary trees of increasing size. The free space map for a given cylinder is preferably a chained free space list.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.