Data Reordering for Read Backward Operations
Original Publication Date: 1981-Mar-01
Included in the Prior Art Database: 2005-Feb-11
In computer systems, data read from input/output devices, such as a tap drive, is entered into a buffer before being transferred to either the central processing unit or storage via the channel. Some computer systems, because of the storage interface, require that the data be sent to the channel in ascending address order even when the data being transferred resulted from a read backward operation of an input/output device. Because of this, it is necessary to reorder the data, and this can be done either as the data is entered into or removed from the buffer. In either instance an address counter specifies the location in the buffer being accessed. Thus, it is necessary for the address counter to generate two address sequences, one for forward and one for backward reading.