Input/Output Device Lock STATE
Original Publication Date: 1989-Feb-01
Included in the Prior Art Database: 2005-Jan-27
This article describes a method used in the input/output (I/O) subsystem of a data processing system that ensures clearing of transparent buffering for an I/O device in a buffered hierarchy of I/O facilities. An I/O device is an addressee in a multi-level I/O hierarchy. In normal operations, the levels of the I/O hierarchy above a target device furnish support to the device in the form of buffering and forwarding of commands, control blocks, data, and interrupts. These buffering functions, and inherent delay that comes with them, represent functions not specifiable in an architecture, nor should they be in order to maintain transparency of the supporting levels to the program specifically responsible for the target device.