Data input and output controller

An input/output control system for an information processing system, comprising a main memory, a central processing unit having an input, a peripheral controller, and a plurality of peripheral units, each coupled to said central processing unit by said peripheral controller, said input/output control system comprising:

• a. a plurality of physical channels disposed between said peripheral controller and said input to said central processing unit;
• b. a plurality of logical channels for communicating information with said central processing unit, each of said logical channels being uniquely associated with one of said peripheral units and identified uniquely by a channel number;
• c. said main memory comprising means for storing a first table including a number of physical channel entries containing in formation relative to said plurality of physical channels and a second table including a number of logical channel entries each containing information relative to one of said plurality of peripheral units, the number of logic channel entries of said second table enabling access to the information contained therein, each physical channel entry corresponding to one of said logical channel tables;
• and
• d. means for storing a channel control program comprising command words for data transfer, said input/output control system executing the channel control programs to selectively transfer data between said main memory and peripheral controller, by connecting said input/output control system to a logical channel entry and placing the identifying number of its logical channel in said means for storing to await execution.