公开(公告)号：JPS63116261A

公开(公告)日：1988-05-20

申请号：JP23275787

申请日：1987-09-18

Applicant: IBM

Inventor： COSTES MICHEL L ,  GACH ALAIN R ,  DUGRE JEAN-PIERRE C

IPC: G06F13/37

公开(公告)号：DE3685114D1

公开(公告)日：1992-06-04

申请号：DE3685114

申请日：1986-10-30

Applicant: IBM

Inventor： COSTES MICHEL L ,  GACH ALAIN R ,  DUGRE JEAN-PIERRE C

IPC: G06F13/37 ,  G06F13/36

Abstract: The priority enhancement circuit has adaptor selecting devices (17,27) to monitor the service requests from various different adapters and to prevent any adapter from raising a new service request whilst the other adapters have requests pending. The grant signal transmitted by an adapter number (n-1) is propagated on the chain directly to a first adapter number (n) on the one hand and to a second adapter number (H + 1), in which case the first adapter is by-passed by the grant signal. A selector device responds to a status signal indicating adapter to determine which of the contending grant signals has to be selected. If the status signal indicates that a given adapter is inoperative it is by-passed.