The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 17, 1999
Filed:
Oct. 28, 1996
Prabhakar Goyal, Sunnyvale, CA (US);
Grama Kasturi Harish, Cedar Park, TX (US);
James Darrell Heath, Austin, TX (US);
Chakravarthy Jagannadhan, Santa Clara, CA (US);
Vishwanath Venkataramappa, Austin, TX (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A system and method for compressing portions of the operating system in a ROM image and for executing the system from the compressed image. Compression is used to reduce the size of the ROM image to reduce component cost. Low use segments are compressed. The operating system is initialized into a virtual address space with entries only for the uncompressed segments. Attempts to execute a compressed segment result in a page fault. The page fault handler determines that the segment is compressed, allocates a new page and decompresses the page into RAM for execution. The RAM copy of the segment is used for execution until the page is reused for another purpose. Later execution causes a new page fault and reallocation. A memory object reference is created for components of the image; a virtual memory page reference is then made for each component not in a compressed form; instructions are then executed by reference to the image; a page fault is detected when attempting to execute an instruction in a component not having a page table reference; a compressed image is then decompressed into the random access memory in response to the page fault.