Read Immediate Data Command
Original Publication Date: 1979-Mar-01
Included in the Prior Art Database: 2005-Feb-20
In certain data processing systems (for instance, refer to IBM System/370 Principles of Operation, Form GA22-7000-5), input/output channels operate independently of central processors to execute programs of chained commands, after having been initiated for each program by a central processor instruction. The operations of the channel in executing such a command program are generally asynchronous to the operations of both the initiating central processor and the supervisory program which controls that processor in respect to the initiation. Under certain conditions the central processor and associated system programs must be able to exert synchronous control over the channel while it is executing its command program.