Original Publication Date: 1984-May-01
Included in the Prior Art Database: 2005-Feb-03
In a computer system it is often necessary to transfer data from main storage to auxiliary storage (Direct Access Storage Device (DASD)), and vice versa. Blocks of data are paged into main storage from auxiliary storage when needed by the operating system. When the main storage pages are no longer needed, they are overwritten or, if altered, they are paged back out to auxiliary storage. A data file consists of one or more pages of main storage or blocks of auxiliary storage. When the file is to be read or written to or from auxiliary storage, a multiple block command is used to read or write the entire file. Fig. 1a shows an 8-block read from auxiliary storage (DASD) to main storage. The data blocks are contiguous on the DASD but need not be contiguous in main storage.