Initial BIOS load for a personal computer system

• US 5,210,875 A
• Filed: 08/25/1989
• Issued: 05/11/1993
• Est. Priority Date: 08/25/1989
• Status: Expired due to Term

• Current Assignee: Lenovo Singapore Pte Limited (Lenovo Group Ltd.)
• Original Assignee: International Business Machines Corporation
• Inventors: Bealkowski, Richard, Dayan, Richard A., Cronk, Doyle S., Blackledge, John W. Jr., Zyvoloski, Kevin M., Sachsenmaier, Robert, Palka, Matthew S. Jr., Kovach, George D., Kinnear, Scott G.
• Primary Examiner(s): Clark, David L.
• Assistant Examiner(s): Wang, Peter Y.
• Application Number:
  US07/398,865
• Time in Patent Office: 1,355 Days
• Field of Search: 364/200, 364/900, 395/700
• US Class Current: 713/2
• CPC Class Codes: G06F 9/4406 Loading of operating system

Abstract

An apparatus and method for loading BIOS stored on a direct access storage device into a personal computer system. The personal computer system comprises a system processor, a system planar, a random access main memory, a read only memory, and at least one direct access storage device. The first portion of BIOS initializes the system and the direct access storage device to read in a master boot record into the system from the direct access storage device. The master boot record includes a data segment and an executable code segment. The first BIOS portion vectors the system processor to execute the executable code segment of the master boot record. The executable code segment loads in the remaining BIOS portion from the direct access storage device into random access memory.

Claims

1. An apparatus for loading an operational interface into a personal computer system, the personal computer system including a system processor and a random access memory electrically coupled thereto, said apparatus comprising:

a direct access storage device being electrically coupled to the system processor, said direct access storage device being capable of storing a plurality of data records;

a master boot record stored on the direct access storage device, said master boot recording including an executable code segment;

a read only memory being electrically coupled to the system processor;

a first portion of the operational interface stored in the read only memory starting at a particular address, said first portion of the operational interface initializing the system and the direct access storage device to load in said master boot record into random access memory; and

a remaining portion of the operational interface stored on the direct access storage device, wherein the first portion of the operational interface transfers control to the executable code segment of the master boot record in order to effect the loading of the remaining portion of the operational interface into the random access memory, said remaining portion of the operational interface being stored starting at said particular address and superseding the first portion of the operational interface and initializing the rest of the personal computer system in order to load in an operating system to begin operation of the personal computer system.

2. The apparatus of claim 1, wherein the direct access storage device comprises a fixed disk.

3. The apparatus of claim 1, wherein the direct access storage device comprises a diskette.

4. The apparatus of claim 1, wherein the master boot record further includes a data segment, the data segment representing a hardware configuration of the personal computer system which is compatible with said master boot record, and further wherein the read only memory includes data representing a hardware configuration of the system processor, wherein before said remaining portion of the operational interface is loaded into random access memory, said first portion of the operational interface compares the hardware configuration data from the master boot record with the hardware configuration data from the read only memory to verify the master boot record is compatible with the system processor.

5. The apparatus of claim 4, wherein the data segment of the master boot record includes a value representing a system planar which is compatible with the master boot record and further wherein the system planar further includes a means for uniquely identifying the system planar in order to verify that the master boot record is compatible to the system planar.

6. The apparatus of claim 4, wherein the hardware configuration data on the master boot record includes a model value and a submodel value, wherein the model value identifies a system processor which is compatible with said master boot record and the submodel value represent an I/O configuration of a system planar which is compatible with the master boot record, and further wherein said read only memory includes a corresponding model value identifying the system processor and submodel value representing the I/O configuration of the system planar, wherein said model value and submodel value of the master boot record are compared to the corresponding model and submodel values of the read only memory respectively, in order to verify that the master boot record is compatible with the system processor and the I/O configuration of the system planar.

7. The apparatus of claim 6, wherein said first portion of the operational interface generates a first error to indicate the master boot record is not compatible with the system hardware.

8. The apparatus of claim 1, wherein the personal computer system further includes a nonvolatile random access memory being electrically coupled to the system processor, said nonvolatile random access memory including data representing the system configuration, said data being updated when the configuration of the system is changed, wherein said first portion of the operational interface compares said data in the nonvolatile random access memory to corresponding data in the read only memory to determine if the configuration of the system has changed.

9. The apparatus of claim 8, wherein said first portion of the operational interface generates a second error to indicate that the system configuration has changed.

10. The apparatus of claim 1, wherein said master boot record includes an identifying means to identify the record in order to distinguish the master boot from other records included on the direct access storage device.

11. The apparatus of claim 10, wherein said identifying means comprises a predetermined character code.

12. The apparatus of claim 11 wherein said predetermined code is prefactory to said code segment of the master boot record.

13. The apparatus of claim 10, wherein said master boot record includes a checksum value to verify the validity of the master boot record when loaded into the random access memory.

14. The apparatus of claim 1, wherein said remaining portion of the operational interface includes a checksum value to verify the validity of the remaining portion of the operational interface when loaded into the random access memory.

15. The apparatus of claim 1, wherein said master boot record includes a predetermined pattern, and further wherein said read only memory includes a corresponding predetermined pattern in order to verify that the first portion of the operational interface is included within a predefined read only memory.

16. The apparatus of claim 15, wherein said executable code segment generates an error to indicate that the read only memory is not compatible with the master boot record.

17. A personal computer system comprising:

a system processor;

a random access memory being the main memory and electrically coupled to the system processor;

a system planar board having a plurality of I/O slots being electrically coupled to the system processor,

a direct access storage device being electrically coupled to the system processor, the direct access storage device capable of storing a plurality of data records;

a master boot record included in the direct access storage device, the master boot record having a data segment and an executable code segment, the data segment representing a hardware configuration of the personal computer system which is compatible with said master boot record;

a read only memory being electrically coupled to the system processor, the read only memory having data representing a hardware configuration of the system;

a first portion of an operational interface being included in the read only memory, said first portion of the operational interface initializing the system and the direct access storage device to load in said master boot record, said first portion of the operational interface further comparing the hardware configuratin data from the master boot record to the hardware configuration data of the read only memory to verify the compatibility of the master boot record with the system processor;

a remaining portion of the operational interface being included in the direct access storage device, wherein after verifying the compatibility of the master boot record with the system processor, the first portion of the operational interface transfers control to the executable code segment of the master boot record in order to effect the loading of the remaining portion of the operational interface into the random access memory, said remaining portion of the operational interface superseding said first portion of the operational interface.

18. The apparatus of claim 17, wherein the data segment of the master boot record includes a value representing a system planar being compatible with the master boot record and further wherein the system planar further includes a means for uniquely identifying the system planar in order to verify the compatibility of the master boot record to the system planar.

19. The apparatus of claim 17, wherein the direct access storage device comprises a fixed disk.

20. The apparatus of claim 17, wherein the hardware configuration data on the master boot record includes a model value and a submodel value, wherein the model value identifies the system processor and the submodel value represent the I/O configuration of the system planar, said model value and submodel value being compared to corresponding values in the read only memory to verify the compatibility of the master boot record to the hardware configuration.

21. The apparatus of claim 17, wherein the personal computer system further includes a nonvolatile random access memory, said nonvolatile random access memory storing values representing the system configuration, said data being updated when the configuration of the system is changed, wherein said first portion of the operational interface compares said values in the nonvolatile random access memory to corresponding values in the read only memory to determine if the configuration of the system has changed.

22. An apparatus for loading an operational interface into a personal computer system, the personal computer system having a system processor being electrically coupled to a random access memory, said apparatus comprising:

a direct access storage device being electrically coupled to the system processor, the direct access storage device being capable of storing a plurality of data records;

a read only memory being electrically coupled to the system processor;

a first portion of the operational interface being included in the read only memory; and

a remaining portion of the operational interface being included in the direct access storage device, wherein the first portion of the operational interface initializes the system processor and direct storage device to effect load the remaining portion of the operational interface into random access memory, said remaining portion of the operational interface effectively superseding the first portion of the operational interface to assist in the operation of the system.

23. A method for loading an operational interface from a direct access storage device of a personal computer system, the personal computer system having a system processor electrically coupled to a system planar, the planar further being electrically coupled to a random access memory, a read only memory, and the direct access storage device, said method comprising the steps of:

(a) initializing the system with a first portion of the operational interface resident in the read only memory;

(b) initializing with the first portion of the operational interface the direct access storage device, the direct access storage device further having a master boot record and the remaining portion of the operational interface;

(c) loading with the first portion of the operational interface the master boot record into random access memory, the master boot record including a data segment and an executable code segment, the data segment having data representing the hardware of the system for which the remaining portion of the operational interface is compatible;

(d) verifying the compatibility of the master boot record with the system hardware by comparing the data representing the system hardware to corresponding compatibility data stored in the read only memory; and

(e) executing the code segment of the master boot record to load the remaining portion of the operational interface into the random access memory; and

(f) passing control to the remaining portion of the operational interface once it is loaded into random access memory.

24. The method of claim 23, wherein step (d) of verifying further includes the steps of:

(g) verifying that the master boot record is compatible with the planar by comparing a planar ID accessible by the system processor with a planar ID value stored in the data segment of the master boot record; and

(h) verifying that the master boot record is compatible with the system processor and I/O configuration of the planar by comparing respectively model and submodel values stored in the read only memory with model and submodel values stored in the data segment of the master boot record.

25. The method of claim 23, wherein the system further includes a nonvolatile memory being electrically coupled to the system processor, wherein the nonvolatile memory includes data representing the system configuration, said method further including the step of:

(i) comparing the data in nonvolatile random access memory to the data in read only memory to determine whether the system configuration has changed; and

(j) generating an indication that the system configuration has changed before loading the operational from the direct access storage device.

26. The method of claim 23, wherein step (c) of loading further includes the steps of:

(k) searching through a predetermined number of records on the direct access image device for a master boot record;

(1) identifying the master boot record with an identifying means included within the master boot record.

(m) loading the master boot record into random access memory upon locating the master boot record among the data records on the direct access storage device.

27. The method of claim 24, further including the step of validating successful load of the master boot record.