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. 27, 2002
Filed:
May. 23, 2000
Rohit Chawla, Spring, TX (US);
Scott W. Dalton, Tomball, TX (US);
Compaq Information Technologies Group, L.P., Houston, TX (US);
Abstract
A computer system has a ROM device containing two separately flashed areas. Each area contains a firmware image. From the factory, the two firmware images are identical. Each image also contains the executable code to flash an image area. The ROM also contains a “boot block” sector that makes decisions as to which of the firmware images is the “active” image and which is the “inactive” image. The active image is copied from the ROM to a RAM device and executed from RAM during normal system operation. The inactive image normally is not executed. The boot block sector also contains code that performs a checksum verification on the active image during initialization and, if the checksum fails, switches the active/inactive status of the two firmware images to make the previously inactive image the active image. With two firmware images, the system can recover from a power failure occurring while flashing the ROM because the other firmware image is still available.