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.

Date of Patent:
Mar. 07, 1995

Filed:

Jan. 18, 1990
Applicant:
Inventors:

Karl-Heinz Schmidt, Aying, DE;

Georg Menache, Munchen, DE;

Wilhelm Waidelich, Munchen, DE;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G06F / ; H04L / ; G11C / ;
U.S. Cl.
CPC ...
395425 ; 395725 ; 380-4 ; 364D / ; 365195 ;
Abstract

A method of protecting programs and data in computers against unauthorized access and modifications employs a programmable hardware circuit to monitor memory regions of a computer. The memory regions are divided into different access levels, and the circuit is programmed to permit access only to predetermined regions. If an unauthorized access is attempted by a program, an address corresponding to the program location initiating the unauthorized access is detected and the program is stopped. This ensures that the procedures for protecting the operating system cannot be circumvented to gain unauthorized access to data of any type. After programming of the circuit is completed, the programming cannot be changed except by actuation of a hardware switch or by re-starting the computer. Removal of the circuit will cause short circuits, thus making it impossible to shut the circuit off without being detected.


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