I/O Key Translation Table
Original Publication Date: 1986-Aug-01
Included in the Prior Art Database: 2005-Mar-09
Currently, input/output (I/O) devices for the IBM Series/1 processor are limited to 512 kilobytes (KB) of addressing. More physical storage on Series/1 is possible via extended architectures. A method is described for the I/O devices to address more than the upper 512 KB of physical storage. For example, ability to expand the 512 KB address into a 16-megabyte (MB) addressing range may be needed. Furthermore, to minimize software impacts and to maintain I/O device compatibility, the Series/1 Device Control Block (DCB)/Immediate Device Control Block (IDCB) I/O control structure is maintained. Thus, the expanded architecture is limited to eight I/O address keys. For supplementary background information, reference is made to the article on page 968 of this issue.