Fail-safe EEPROM based rewritable boot system

Patent 5432927 Issued on July 11, 1995. Estimated Expiration Date:

November 17, 2014. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

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Inventors

Application

No. 340803 filed on 11/17/1994

US Classes:

713/2, Loading initialization program (e.g., booting, rebooting, warm booting, remote booting, BIOS, initial program load (IPL), bootstrapping)711/103, Programmable read only memory (PROM, EEPROM, etc.)711/115, Detachable memory714/2, Fault recovery714/7, Reconfiguration (e.g., adding a replacement storage component)714/17Reexecuting single instruction or bus cycle

Examiners

Primary: Beausoliel, Robert W. Jr.
Assistant: Tu, T.

Attorney, Agent or Firm

Calfee Halter & Griswold

International Classes

G06F 011/34
G06F 011/00

Abstract

A computer boot strap loading system employs dual, separable EEPROM units to facilitate safe reprogramming of bootstrap loader software. Both EEPROMs are adapted for storing bootstrap loading code. One of these two EEPROM areas is designated as the unit for which the code content will govern operation of the next reboot sequence. Circuitry is provided to monitor progress of a reboot to determine if a defect in the presently utilized reboot sequence is provided. Such a defect triggers a reboot from the other EEPROM as well as to provide a back-up copy of the bootstrap loading code most recently determined to be effective.

Other References

Dialog Printout
Rosch, Winn, "FlashCard's Flash Memory Delivers Security for Diskless Workstations," PC Magazine, May, 1991, p. 49
Soja, Richard, "single Chip MCU EEPROM Programming Using Bootstrap Techniques," Electronic Engineering, Oct. 1988, pp. 75-80
"Research Disclosure Index," Research Disclosure, Jun. 1991 326, p. 427
"MC68705P3 Advance Information," Motorola Microcomputer, 1984, pp. 3-827-3-85