Solid-state RAM data storage for virtual memory computer using fixed-sized swap pages with selective compressed/uncompressed data store according to each data size
US5490260A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 2, 1991 |
| Grant date | Feb 6, 1996 |
| Priority date | — |
| Expiry date | Apr 2, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2212/401
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A computer using virtual memory management employs a random-access type storage device such as a semiconductor memory for page swapping. The semiconductor memory is formatted to provide multiple partitions of varying block size, e.g., two block sizes, for compressed pages, and another block size for uncompressed original-sized pages. The data to be stored is in pages of fixed size, and these pages are compressed for storage if the compressed size fits in the block size of one of the small-block partitions in the memory. If a data page is not compressible to one of the small block sizes, it is stored uncompressed in the other full-size partition. The operating system maintains a table storing the locations of the pages in the partitions, so upon recall the page (if compressed) is retrieved from its location found using the table, decompressed and sent to the CPU. The relative number of blocks in the partitioned memory (e.g., the physical storage capacity of the memory) is set (or dynamically allocated) at the average ratio of compressible pages to uncompressible pages for the compression algorithm used. For example, an algorithm may compress 90% of the pages to either 50% or 70% of …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.