Abstract: In order to allow a plurality of remote data processing systems (1, 2) to communicate with one another by means of a storage unit (8) shared among these remote systems, each data processing system (1, 2) has the capability to reserve itself temporary exclusive access to the storage unit (8) by means of atomic operations. One particular atomic operation used is comprised of replacing a current value of a register (OPA) in the storage unit (8) with a new value communicated by the data processing system (1, 2) remote from the storage unit, it being understood that the remote data processing system knows an old value of the register (OPA) that is not necessarily equal to its current value. A device is installed in a storage controller (7, 16, 27) for the purpose of executing the atomic operation locally relative to the storage unit (8).

Abstract: Electrical circuit (5) arranged to move data blocks from a source memory unit (8, 9, 12) to a target memory unit (9, 12, 8) by a data path (5, 6, 7), to send, in a given order, requests to read blocks in the source memory, to generate an end marker in the request to read the last block of the source memory, to receive the blocks read, in the form of response messages, in the order in which the requests were sent, and to send requests to write the received blocks, in the target memory, during receiving of response messages until receiving a message from the source memory with the end marker.

Abstract: An information processing system includes processors grouped in nodes (1) associated with one another by links (4) in a variable number of nodes up to the maximum configuration, which is divided into subsets (3) having a critical size relative to a rate of messages between nodes, the nodes in one subset being connected to one another by double serial links, and the nodes of two adjacent subsets being connected by single serial links, the nodes preferably being grouped in two supernodes including two subsets (3).