James M Brewer

US Patent:

43631258, Dec 7, 1982

Filed:

Dec 26, 1979

Appl. No.:

6/106633

Inventors:

James A. Brewer - Boulder CO
John A. Lowy - Tucson AZ

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 1100
G11C 2900

US Classification:

371 71

Abstract:

A high speed readback check of data transferred to a cyclic memory before the data source is lost. The cyclic memory is organized into a number of data blocks, each interleaved with or simultaneously accessible with the other data blocks. Thus, a long data record comprises several data blocks and therefore several cycles of the memory. A readback check of data transferred from a source into the memory is accomplished by writing data into one data block in a first cycle, writing data into another block on the second cycle while reading back the first data block and calculating a check character therefrom, continuing through the writing of the entire record, and reading the last block of written data and calculating the check character, and then comparing the calculated check character with a character calculated from the source data to detect any error before the source of the record is lost.