Browse Prior Art Database

Channel Allocation Monitor and Controller

IP.com Disclosure Number: IPCOM000090595D
Original Publication Date: 1969-May-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 26K

Publishing Venue

IBM

Related People

Ashany, A: AUTHOR [+4]

Abstract

Central processing unit CPU operates with control units CU for I/O devices through channels C1...C4 and shared channel circuitry. The control units are located, on eight strings which are connected to the channels through a crosspoint switch. The crosspoint switch is controlled by a channel allocation monitor end controller CAMAC. The crosspoint switch is operated to interconnect the control unit strings and channels in a selected pattern. The CAMAC includes logic for controlling the crosspoint switch to assign the control unit strings to the channels. A CU string can be switched from a busy or inoperable channel to an available channel. The CPU provides CU addresses without regard to the actual status of the crosspoint switch.

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Channel Allocation Monitor and Controller

Central processing unit CPU operates with control units CU for I/O devices through channels C1...C4 and shared channel circuitry. The control units are located, on eight strings which are connected to the channels through a crosspoint switch. The crosspoint switch is controlled by a channel allocation monitor end controller CAMAC. The crosspoint switch is operated to interconnect the control unit strings and channels in a selected pattern. The CAMAC includes logic for controlling the crosspoint switch to assign the control unit strings to the channels. A CU string can be switched from a busy or inoperable channel to an available channel. The CPU provides CU addresses without regard to the actual status of the crosspoint switch. In CAMAC, the addresses from CPU are translated by a table look-up memory to addresses that correspond to the status of the crosspoint switch. CAMAC also provides inverse address translation for converting the CU addresses to the form used by the CPU Thus, CAMAC is transparent to the programs except for certain diagnostic operations. If more than one CPU is used, each CPU is provided with a CAMAC that controls a corresponding portion of a common crosspoint switch.

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