Method and system for efficient format, read, write, and initial copy processing involving sparse logical units

摘要

A method and system for eliminating null I/O operations that transfer null data during processing of FORMAT and INITIAL-COPY I/O device commands and READ and WRITE I/O requests by an I/O device. Indications of whether or not a particular logical unit is sparsely populated with data are stored in the I/O device, along with bit maps indicating null tracks for sparse logical units. By referencing the stored indications and bit maps, the I/O device controller can recognize null operations that may be safely eliminated, saving processing and data transfer resources and eliminating time delays.