Isolated multiprocessing system having tracking circuit for verifyng only that the processor is executing set of entry instructions upon initiation of the system controller program
US5551051A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 20, 1994 |
| Grant date | Aug 27, 1996 |
| Priority date | — |
| Expiry date | Sep 20, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F21/53
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A computer (20) includes a hardware memory access enforcer (50) to insure that various independent programs (52, 54) operating on the computer (20) follow isolated processing rules. Each program has its own memory domain (56), which may extend across instruction, data, and I/O memory spaces (40, 42, 44). A system controller program (52) is a trusted process. The system controller (52) may access memory in the domain (56) of any application (54), and program flow may exit system controller (52) to any application (54). However, applications (54) cannot access memory outside of their own domains (56), and program flow may not exit applications (54) to enter other applications (54). Program flow may exit applications (54) to system controller (52) only if directed to an entry address (60). A tracking circuit (74) verifies that a microprocessor (22) actually executes entry instructions (94) located at the entry address (60).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.