公开(公告)号：US2861200A

公开(公告)日：1958-11-18

申请号：US45938154

申请日：1954-09-30

Applicant: IBM

Inventor： HENLE ROBERT A ,  EMERY RAYMOND W ,  BRUCE GEORGE D ,  MAC SORLEY OLIN L

IPC: H03K3/012 ,  H03K3/286 ,  H03K3/288

CPC classification number: H03K3/288 ,  H03K3/012 ,  H03K3/286

公开(公告)号：CA1030267A

公开(公告)日：1978-04-25

申请号：CA225414

申请日：1975-04-22

Applicant: IBM

Inventor： LEBIZAY GERALD ,  KERRIGAN MICHAEL ,  MAC SORLEY OLIN L ,  WEISS ALFRED

IPC: G06F13/36 ,  G06F13/34

Abstract: An input-output port control subsystem for use with a computer system having separate source and destination buses incorporated therein. Said system including circuitry for controlling operations of said system and said input/output subsystem, said subsystem including a bidirectional input/output bus for transferring data to and from said system, and separate gating means for selectively connecting said source and destination buses to said bidirectional I/O bus. External devices are connected to said bus thru an adaptor unit which is directly connected to said processing system by appropriate control lines. The input/output subsystem is adapted to operate either under programmed I/O control mode thru the central processing system or in cycle steal mode wherein the I/O devices themselves request cycle steal service time on the I/O bus thru their connected adaptor.