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:
Dec. 16, 2003
Filed:
Aug. 03, 2000
Stephanie Maria Forsman, Rochester, MN (US);
Shawn Michael Lambeth, Pine Island, MN (US);
Chetan Mehta, Austin, TX (US);
Paul Edward Movall, Rochester, MN (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method and an apparatus is presented for updating flash memory that contains a write protected code, a first copy of rewritable recovery code, a second copy of rewritable recovery code, and a rewritable composite code. Each block of rewritable code contains a checksum code to detect if the block of code has been corrupted. If it is detected that the first copy of the recovery code is corrupted then the second copy of the recovery code is copied into the first copy of the recovery code. If it is detected the second copy of the recovery code is corrupted then the first copy of the recovery code is copied into the second copy of the recovery code. The recovery code is responsible for checking and updating the composite code. If it is detected the composite code is corrupted then a fresh copy of the composite code is obtained from a removable storage device or a network connection. The data processing system is booted by executing the write protected code, the first copy of the recovery code, and the composite code. There is a minimum of redundant code by only replicating two copies of the recovery code while, at the same time, guaranteeing both the integrity and the updateability of the flash memory.