EP0606771A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method and apparatus for providing enhanced data verification in a computer system
Assignee: International Business Machines Corp
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Filing: 1993-12-29
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Granted: —
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Expires: 2013-12-29
Abstract
Abstract A personal computer system compatible with application programs and operating system software. The personal computer system includes a microprocessor (300) electrically coupled to a data bus (322), non-volatile memory (308) electrically coupled to the data bus, volatile memory (312) electrically responsive to the data bus and a direct access storage device (108,324) electrically responsive to the data bus, the direct access storage device storing a second portion of operating system microcode. The non-volatile memory stores a first portion of operating system microcode and the direct access storage device stores a second portion of operating system microcode. The second portion of operating system microcode includes a boot program. The first portion of operating system microcode verifies the integrity of the boot program prior to loading the boot program into the volatile memory.
Inventors
- 👤 William Carlisle Arnold
- 👤 Richard Bealkowski
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 13:25
CPC Classifications
G; G06; G06F; G06F21/00; G06F21/50; G06F21/57; G06F21/575; G06F11/00; G06F11/22; G06F21/55; G06F21/56; G06F21/562; G06F21/565; G06F9/00; G06F9/06; G06F9/44; G06F9/4401; G06F9/4403
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
126 words
A personal computer system compatible with application programs and operating system software, the personal computer system comprising: a microprocessor electrically coupled to a data bus; non-volatile memory electrically coupled to the data bus, said non-volatile memory storing a first portion of operating system microcode; volatile memory electrically responsive to the data bus; a direct access storage device electrically responsive to the data bus, said direct access storage device storing a second portion of operating system microcode, said second portion of operating system microcode including a boot program; at least a first verifying means for verifying the integrity of said boot program prior to loading said boot program into said volatile memory, said first means for verifying being integral with said first portion of operating system microcode.
Claim 2
Dependent Claim
35 words
A personal computer system according to claim 1, wherein said first verifying means includes means for generating an initial modification detection code based upon said boot program during an initial setup of the computer system.
Claim 3
Dependent Claim
34 words
A personal computer system according to claim 2, wherein said means for generating includes a cryptographic one-way function which calculates a multi-byte value from a given input series of bytes of said boot program.
Claim 4
Dependent Claim
36 words
A personal computer system according to claim 2 or claim 3, wherein said non-volatile memory includes a check code portion, and said first verifying means stores said initial modification detection code in said check code portion.
Claim 5
Dependent Claim
40 words
A personal computer system according to claim 4, wherein said check code portion of said non-volatile memory is disabled to prevent writing to said check code portion after said initial modification detection code is stored in said check code portion.
Claim 6
Dependent Claim
81 words
A personal computer system according to claim 4 or claim 5, wherein said first verifying means compares a present modification detection code upon power-up of the computer system with said initial modification detection code, said first verifying means including means for taking corrective action if said present modification detection code does not correspond to said initial modification code, said first verifying means transferring control to said boot record if said present modification detection code corresponds to said initial modification detection code.
Claim 7
Dependent Claim
42 words
A personal computer system according to any one of claims 4 to 6, wherein said non-volatile memory includes a flag portion, and said first verifying means stores in said flag portion a flag to indicate the presence of said modification detection code.
Claim 8
Dependent Claim
80 words
A personal computer system according to any one of the preceding claims wherein said direct access storage device stores said second portion of operating system microcode in a first portion of the direct access storage device and the operating system software in a second portion of the direct access storage device; the computer system further comprising a second verifying means for verifying the integrity of the operating system software prior to loading the operating system software into said volatile memory.
Claim 9
Dependent Claim
17 words
A personal computer system according to claim 8, wherein said boot program includes said second verifying means.
References Cited (Backward Citations)
No citation records indexed.
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