International Business Machines Corporation

Richard Scott Maxwell

Andrew Ian Hickson

David Ware

Andrew David Banks

Daniel Noel Millwood

Timothy Steven Raff

The invention relates to a method, apparatus and computer program for reducing the number of data elements checkpointed in a system having at least one data store where operations on said at least one data store are recorded in a log. A point in the log is recorded. The oldest data element in each of the least one data store is determined and it is then determined for each of the at least one data store whether a logged representation of the data store's oldest data element is more recent than the point recorded. Responsive to determining that a data store's logged representation is more recent than the point recorded, it is realised that it is not necessary to force data elements from that data store to disk if the point recorded is made the point of restart for that data store.

Method, apparatus and computer program for reducing the amount of data checkpointed

Provided are a method, computer program product and data processing apparatus for recovery from interprocess communication failures, the method comprising: in response to an initiator process requesting interprocess communication (IPC) with a responder process via an IPC link, recognizing if the initiator process does not have the expected write control of the IPC link and setting an indicator. A process other than the initiator process checks the indicator (such as after a timeout, or periodically) and, if the indicator has been set, notifies the initiator process to take control. This method avoids potential stalemate situations in which neither the initiator nor the responder process can take control, without reliance on mutex locks for every exchange of data and control.

Interprocess communication mechanism

A data processing apparatus for carrying out workload management with respect to a group of servers in an asynchronous client/server computing system, has: a device for receiving a work request from a client application; a device for consulting availability data concerning the group of servers and for selecting a particular server in the group to be used to satisfy the received work request on the basis of the consulted availability data, where the consulted availability data is always used in its present state when the work request is received, irrespective of whether availability data has been received for each server in the group, in order to select a server from the group; and a device for placing the received work request in a transmission queue where it awaits transmission to the particular server in the group.

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Romsey, United Kingdom

Richard Scott Maxwell