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:
Jan. 30, 2001
Filed:
Apr. 07, 1993
B. Tod Cox, Houston, TX (US);
Peter J. Michels, Cypress, TX (US);
Michael R. Kluth, Tomball, TX (US);
Jeffrey S. Watters, Beaverton, OR (US);
Compaq Computer Corporation, Houston, TX (US);
Abstract
A computer system having a system ROM comprising a flash or bulk EPROM replacing a block flash or boot block EPROM, and a second ROM to store the primary boot code. In a first embodiment, a single block EPROM is replaced with a bulk EPROM and a ROM, where the ROM is preferably a one-time programmable ROM. The primary boot code is copied into the ROM thereby preventing its erasure. The bulk EPROM is reprogrammed if desired. Separate decode logic detects an address to the primary boot code and enables the ROM. In a second system using a block EPROM and a bulk EPROM as the system ROM, the block EPROM is replaced with a bulk EPROM, and the primary boot code is copied into both bulk EPROMs, preferably at mirrored locations. An external switch is provided with appropriate logic, so that the user may select between either of the bulk EPROMs to boot the system. Thus, if the system is unable to boot from one of the bulk EPROMs, the user may flip the switch to access the primary boot code from the other bulk EPROM. A software program is executed after successful reboot to reprogram and verify the contents of both of the bulk EPROMs. The software reprograms and verifies one bulk EPROM and then reprograms and verifies the other to assure data integrity.