Browse Prior Art Database

Resource Control Unit

IP.com Disclosure Number: IPCOM000081400D
Original Publication Date: 1974-May-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Myers, JJ: AUTHOR

Abstract

There is described herein a unit which enables the synchronizing of the usage of serially-reusable resources by independent CPU's. The unit, termed "Resource Control Unit" (RCU), is a structure which is accessible by independent CPU's which control the allocation of such serially-reusable resources.

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Resource Control Unit

There is described herein a unit which enables the synchronizing of the usage of serially-reusable resources by independent CPU's. The unit, termed "Resource Control Unit" (RCU), is a structure which is accessible by independent CPU's which control the allocation of such serially-reusable resources.

The RCU accepts three commands, viz: 1) TAR - test and allocate resource.
2) RR - release resource. 3) ERR - emergency release resource.

Definitions utilized in the operation of the RCU are the following:
SID - system id - a unique identifier (Not Equal 0) of each CPU which can access the RCU.

RID - resource id - a unique identifier (Not Equal 0) of each resource whose allocation is controlled by

the RCU.

RAR - resource allocation register - one register for each allocatable resource, respectively. The contents

in RAR are 0 if the resource is not allocated. Its

contents are the SID of the CPU using the resource if

the resource has been allocated thereto.

In the operation of the RCU, the TAR command requests the RCU to allocate the resource specified by an RID to the CPU specified by the SID. The RCU will then allocate the resource if the RAR = 0 or the RAR = SID. Otherwise, the RCU will reject the request. The output of the TAR command is the OID (owner id) which will be equal to the SID if the request was accepted. Otherwise, the OID and SID will not be equal. The RCU returns a busy status to any other commands which are received while it is proc...