Mapped file input/output with delayed zeroing
US5920895A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 24, 1995 |
| Grant date | Jul 6, 1999 |
| Priority date | — |
| Expiry date | Apr 24, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F12/1491
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The efficiency of writing files that are cached using mapped file I/O is improved by suppressing zeroing of uninitialized data in cached pages of a file until the file is mapped by a user mode thread. In an operating system where paging operations are controlled by a virtual memory manager and memory based caching using mapped file I/O is administered by a cache manager, suppressing zeroing of mapped files on writes is implemented by a set of internal operating system interfaces for communications between the virtual memory manager and the cache manager. When a file being cached is not yet mapped by a user mode thread, the cache manager tracks the extent to which a cache page of the file is written so that any uninitialized data in the cache page can later be zeroed when the file is mapped by a user mode thread.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.