Digital memory with automatic overwrite protection
Abstract
Abstract THERE IS DISCLOSED A DIGITAL COMPUTER IN WHICH WORDS IN MEMORY MAY EACH HAVE A SPECIAL BINARY BIT THAT IS SET TO ONE, FOR EXAMPLE, TO PREVENT THAT WORD FROM BEING CHANGED. WHENEVERY A PARTICULAR COMMAND ATTEMPS TO WRITE A NEW WORD IM MEMORY, THE SPECIAL BIT IS SENSED IN THE MEMORY BUFFER ON READING OUT THE EXISTING WORD AT THE START OF THE MEMORY CYCLE, AND, IF THE BIT HAS BEEN SET TO ONE, THE NEW WORD IS REJECTED AND THE EXISTING WORD IS AUTOMATICALLY RESTORED IN THE SAME LOCATION IN MEMORY. THE EXISTING WORD IN MEMORY IS ALSO TRANSMITTED TO THE PROCESSOR. THE PROCESSOR IS INTERRUPTED BY THE PRESENCE OF THE SPECIAL BIT IN THE WORD TRANSMITTED FROM MEMORY, INDICATING THAT A PROTECTED LOCATION IN MEMORY HAS BEEN ADDRESSED.
Inventors
- 👤 Bobby A Creech
- 👤 Erwin A Hauck
- 👤 Carl B Carlson
- 👤 Iver C Hansen
Bibliographic Details
Claims Analysis
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