[li] Patent Number: 4,959,768  Date of Patent: Sep. 25,1990
 APPARATUS FOR TRACKING
PREDETERMINED DATA FOR UPDATING
A SECONDARY DATA BASE
 Inventor: Paul B. Gerhart, Horsham, Pa.
 Assignee: Honeywell Inc., Minneapolis, Minn.
 Appl. No.: 299,857
 Filed: Jan. 23, 1989
 Int. CI.* G06F 11/20
 U.S. CI 364/187; 371/9.1
 Field of Search 364/187; 371/9.1
 References Cited
U.S. PATENT DOCUMENTS
4,031,372 6/1977 Davis 371/9.1
4,351,023 9/1982 Richer 371/9.1
4.581.701 4/1986 Hess et al 371/9.1
4.751.702 6/1988 Beier et al. 371/9.1
FOREIGN PATENT DOCUMENTS 2032149 4/1980 United Kingdom 371/9.1
Primary Examiner—Allen MacDonald
Attorney, Agent, or Firm—Arthur A. Sapelli; D. J.
Lenkszus; A. Medved
A process control system includes a primary processor connected to a primary memory via a bus. The primary processor transfers data to be stored to said primary memory. An apparatus of the present invention connected to the bus, collects predetermined data of the data being transferred simultaneously with the transfer of the data to the primary memory. The predetermined data collected by the apparatus is subsequently transferred to a backup processor controller to update the data base of the backup process controller. The apparatus comprises a storage element which stores the data collected. A logic unit controls the operation of the apparatus including the collection of the predetermined data. A control unit of the apparatus transfers the predetermined data stored in the storage element to the backup process controller.
2 Claims, 4 Drawing Sheets