Automated programmable fireware store for a personal computer system

• US 5,826,075 A
• Filed: 11/27/1991
• Issued: 10/20/1998
• Est. Priority Date: 10/16/1991
• Status: Expired due to Term

• Current Assignee: Lenovo PC International Limited (Lenovo Group Ltd.)
• Original Assignee: International Business Machines Corporation
• Inventors: Begun, Ralph Murray, Bealkowski, Richard
• Primary Examiner(s): AMSBURY, WAYNE P
• Application Number:
  US07/799,486
• Time in Patent Office: 2,519 Days
• Field of Search: 395/800, 395/700, 395/425, 395/600, 364/927.82, 371/19, 380/4
• US Class Current: 713/187
• CPC Class Codes: G06F 11/1433 during software upgrading

Abstract

An automated programmable firmware store for a personal computer system includes a plurality of nonvolatile alterable electronic memories connected in a mutually paralleled circuit arrangement. The memories are connected to a means for automatically controlling the memories to read firmware from and write firmware into the electronic memories, and to write-protect at least one of the memories. Any memory can be write-protected as initially selected by the automatic control means. The initial selection can be changed easily to write-protect another of the memories. The firmware in one memory includes code for checking the validity of firmware stored in another memory, and for selecting one or the other of the memories dependent upon a version code of the firmware. The control means also includes an update code for updating the firmware in a selected memory. The automated store further includes means for allowing the computer system to recover automatically from invalid firmware stored in one of the memories.

Claims

1. An apparatus for storing firmware, including:

a plurality of nonvolatile alterable electronic memory devices connected in an electrically mutually parallel circuit arrangement;

each said memory device storing firmware for controlling operation of a computer system, each said memory device being reprogrammable while in a said computer system to store either the same said firmware or an updated version thereof, and each said memory device being of a type which is potentially vulnerable to loss of data while the device is being reprogrammed; and

control means electrically connected to said memory devices for automatically and selectively controlling the accessibility of said memory devices to be read or written by a said computer system, such that at any instant of time only a single selected one of said memory devices is enabled to be accessed by said computer system at any time, and such that said selected one of said memory devices is adaptively selectable by said control means in response to conditions encountered during startup of a said computer system;

whereby, a said memory device first selected during said computer system startup and having invalid firmware can be automatically replaced by another of said memory devices prior to completion of said startup.

2. An apparatus as claimed in claim 1, wherein said control means includes means for conditionally write protecting said memory devices such that a said selected memory device that is currently enabled for read or write access by a said computer system can be reprogrammed to contain a new copy of said firmware only by a party having a special authorization identity.

3. An apparatus as claimed in claim 1, wherein said control means includes means for automatically controlling enablement of said memory devices to be written to, and thereby reprogrammed, by a said computer system, such that a single selected one of said devices can be reprogrammed without affecting the memory content of any other said memory devices.

4. An apparatus as claimed in claim 3, wherein said means for controlling reprogramming access to said memory devices further includes means for automatically write protecting the memory content of said any other memory devices.

5. An apparatus as claimed in claim 3, wherein said memory devices are configured by said control means into an active/standby configuration in which only a single selected one of said memory devices is active relative to a respective said computer system at any instant of time, and only said single selected one of said memory devices is being used to furnish firmware to said computer system;

and wherein any other one of said memory devices, that is not currently selected, is available, on a standby basis, to be selected to replace said single selected one of said one memory devices.

6. An apparatus as claimed in claim 5, wherein said control means includes an enable logic device having outputs connected to said memory devices and having an input connected to a signal generator, said logic device including logic for selecting different ones of said memory devices, as said single selected one of said memory devices, in response to signals from said signal generator.

7. An apparatus as claimed in claim 6, wherein said enable logic device further includes selective write enabling logic for enabling said any other one of memory devices to be reprogrammed while simultaneously preventing alteration of the memory content of said single selected one of said memory devices.

8. An apparatus as claimed in claim 6, wherein said signal generator includes means for automatically selecting said another of said memory devices.

9. An apparatus as claimed in claim 6, wherein said signal generator includes means for generating a processor reset signal.

10. An apparatus as claimed in claim 1, wherein said control means is adapted for performing a Bank Check and Select function, relative to said any other one of said memory devices, for generating a validity check on the memory content of said any other one of said memory devices, for ascertaining a characteristic of said memory content, and for selecting said one or said another memory device dependent upon said characteristic.

11. An apparatus as claimed in claim 10, wherein said firmware is available in a number of different versions and said characteristic is indicative of a specific one of said different versions.

12. An apparatus as claimed in claim 10, wherein said Bank Check and Select function is defined by the firmware stored within said single selected one of said memory devices.

13. A personal computer system having an alterable firmware store, comprising:

a processor;

an electronic volatile memory, said memory being electrically connected to said processor;

a plurality of alterable electronic nonvolatile memories connected in a mutually parallel circuit arrangement, said nonvolatile memories being electrically connected to said processor and to said volatile memory;

firmware stored within each of said nonvolatile memories;

said nonvolatile memories being reprogrammable by operations of said computer system, and also being of a type which is vulnerable to potential loss of firmware data while being reprogrammed,

means for automatically controlling access to said nonvolatile memories to permit an alteration of said firmware stored within one of said nonvolatile memories, while preventing alteration of said firmware stored within any other one of said nonvolatile memories.

14. A personal computer system as claimed in claim 13, wherein said means for automatically controlling access to said nonvolatile memories includes means for controlling reprogramming access to said one of said nonvolatile memories to allow for alteration of the firmware stored within said one nonvolatile memory.

15. A personal computer system as claimed in claim 14, wherein said altering means includes an update enable code for allowing alteration of firmware stored within said one nonvolatile memory.

16. A personal computer system as claimed in claim 15, wherein said update enable code includes a plurality of code elements, including one element for selecting said one nonvolatile memory as an active memory, another element for enabling said one nonvolatile memory to receive a new firmware image, and vet another element for enabling writing of said new firmware image into said one nonvolatile memory.

17. A personal computer system as claimed in claim 16, wherein said firmware includes a Bank Check and Select Code for checking a validity of firmware stored in a selected one of said memory devices, for ascertaining a characteristic of the said stored firmware, and for selecting either said one memory device containing said checked firmware or another one of said memory devices other than said device containing said checked firmware as the source of firmware to be read out to said computer system when said system is fully operational, in functional dependence upon said checked characteristic.

18. A personal computer system as claimed in claim 17, wherein said firmware includes a POST program for checking said computer system when said system is booted up, and wherein said Bank Check and Select Code is a part of said POST program.

19. A method as claimed in claim 17, further comprising storing complete firmware images respectively within the one and the another of the memory banks prior to said first selecting step.

20. A method as claimed in claim 19, wherein the complete firmware images are identical.

21. A method for accessing firmware in a personal computer system, comprising:

automatically first selecting one of a plurality of memory banks, each having respective firmware stored therein as a source of firmware to be read out to the respective computer system;

each of said memory banks of said plurality of memory banks comprising a nonvolatile memory device that is reprogrammable to contain a new version of said firmware, and each said memory device being of a type which is vulnerable to potential loss of data while the device is being reprogrammed;

checking a validity of the firmware stored in another one of said memory banks;

comparing a characteristic of the firmware stored in said one of said memory banks with a characteristic of the firmware stored in said another one of said memory banks to produce a result;

second selecting between said one and said another one of said memory banks as the said source of firmware to be read out to said computer system dependent upon the result of said comparing step.

22. A method as claimed in claim 21, further comprising copying the firmware from said bank selected in said second selecting step into a volatile memory of said computer system.

23. A method as claimed in claim 21, further comprising:

enabling said another one of said memory banks to receive a new firmware image and then;

writing the new firmware image into said another bank.