Computer system

Claim 2

In a parallel computer system having at least a primary task performing means (11), a second primary task performing means (21), a secondary task performing means (22) acting as a backup for said second primary task performing means (21), each of said task performing means (11,21,22) having a task performing memory means, and a message bus means (MB) interconnecting said task performing means (11,21,22), the method of transferring messages among said task performing means comprising the steps of: sending messages from said primary task performing means (11) to said second primary task performing means (21), said second primary task performing means (21) operating on said messages by initially storing a received message in a queue (MQ) and thereafter reading the message from the queue (MQ) for processing in accordance with the task associated with said second primary task performing means (21), said second primary task performing means (21) accumulating a count of the messages read from its queue (MQ), and sending said messages from said first primary task performing means (11) to said secondary task performing means (22), said secondary task performing means (22) storing said messages in a message queue (MQ).

Claim 3

The method as claimed in claim 1 further comprising the step of counting the messages sent by said first primary task performing means (11).

Claim 4

The method as claimed in claim 1 or 2 further comprising the step of said first primary task performing means (11) transmitting a message only after both said secondary primary task performing means (21) and said secondary task performing means (22) indicate to said first primary task performing means (11) that they can receive the message.

Claim 5

The method as claimed in claim 2 further comprising the step of both said second primary task performing means (21) and said secondary task performing means (22) indicating to said primary task performing means (11) that they have received the message.

Claim 6

In a parallel computer system having at least a first primary task performing means (11), a first secondary task performing means (12) acting as a backup for said first primary task performing means (11), a secondary primary task performing means (21), a second secondary task performing means (22) acting as a backup for said second primary task performing means (21), each of said task performing means (11, 12, 21, 22) having a task performing memory means, and a message bus means (MB) interconnecting said task performing means (11, 12, 21, 22), the method of transferring messages among said task performing means (11, 12, 21, 22) comprising the steps of: sending messages from said first primary task performing means (11) to said second primary task performing means (21), said second primary task performing means (21) operating on said messages by initially storing a received message in a queue (MQ) and thereafter reading the message from the queue (MQ) for processing in accordance with the task associated with said second primary task performing means (21), said second primary task performing means (21) accumulating a count of the messages read from its queue (MQ), and sending said messages from said first primary task performing means (11) to said second secondary task performing means (22), said second secondary task performing means (22) storing said messages in a message queue (MQ).

Claim 7

In a parallel computer system having at least a first primary task performing means (11), a first secondary task performing means (12) acting as a backup for said first primary task performing means (11), a secondary primary task performing means (21), a second secondary task performing means (22) acting as a backup for said second primary task performing means (21), each of said task performing means (11, 12, 21, 22) having a task performing memory means, and a message bus means (MB) interconnecting said task performing means (11, 12, 21, 22), the method of transferring messages among said task performing means (11, 12, 21, 22) comprising the steps of: sending messages from said first primary task performing means (11) to said second primary task performing means (21), said second primary task performing means (21) operating on said messages by initially storing a received message in a queue (MQ) and thereafter reading the message from the queue (MQ) for processing in accordance with the task associated with said second primary task performing means (21), said second primary task performing means (21) accumulating a count of the messages read from its queue (MQ), and sending said messages from said first primary task performing means (11) to said second secondary task performing means (22), said second secondary task performing means (22) storing said messages in a message queue (MQ).

Claim 8

The method as claimed in claim 5 wherein said first primary task performing means (11) also sends said messages from said first primary task performing means (11) to said first secondary task performing means (12), said first secondary task performing means (12) counting the number of messages emitted from said first primary task performing means (11).

Claim 9

The method as claimed in claim 5 or 6 further comprising the step of said first primary task performing means (11) transmitting a message only after all three other task performing means (12, 21, 22) indicate to said first primary task performing means (11) that they can receive the message.

Claim 10

The method as claimed in claim 7 further comprising the step of all three other task performing means (12, 21, 22) indicating that they have received the message.

Claim 11

The method as claimed in claim 5 wherein said second primary task performing means (21) and said second secondary task performing means (22) have access to a common memory means (CM), and whenever the messages in the queue (MQ) of said second secondary task performing means (22) exceeds a predetermined amount said second primary task performing means (21) transfers the contents of its task performing memory means to said common memory means (CM), transferring the accumulated count of the read messages to said second secondary task performing means (22), and zeroing said accumulated count as stored in said second primary task performing means (21).

Claim 12

The method as claimed in claim 9 wherein said second primary task performing means (21) becomes inoperative said second secondary task performing means (22) begins operating on the messages in its message queue (MQ) utilising the data stored in said common memory means (CM) but after discarding the first n messages in its message queue (MQ), n being the accumulated count number received from said secondary primary task performing means (21).

Claim 13

The method as claimed in claim 6 wherein said secondary primary task performing means (21) and said second secondary task performing means (22) have access to a common memory means (CM), and whenever the messages in the queue (MQ) of said second secondary task performing means (22) exceed a predetermined amount said second primary task performing means (21) transfers the contents of its task performing memory means to said common memory means (CM) and transfers the accumulated count of the read messages to said secondary task performing means (22), said second primary task performing means (21) sending p messages to another task performing means, said second secondary task performing means (22), accumulating a count of the Q messages sent by said second primary task performing means (21), after sending said p messages said second primary task performing means (21) becoming inoperative, said second secondary task performing means (22) beginning processing the messages in its message queue (MQ) utilising the date stored in said common memory means (CM) but after discarding the first n message therein, n being the accumulated count number received from said second primary task performing means (21) and not sending the first p messages generated from the start of its taking over processing.

Claim 14

In a parallel computer system having at least a first primary task performing means (11), a second primary task performing means (21) and a first secondary task means (12), each of said task performing means (11,21) having a task performing memory means, and a message bus means (MB) interconnecting said task performing means (11,21), the method of transferring messages among said task performing means (11,21) comprising the steps of: sending n messages from said first primary task performing means (11) to said secondary primary task performing means (21), storing the count n of the messages sent, and said first secondary task performing means (12) starting processing upon failure of said first primary task performing means (11) but omitting the sending of the first n messages resulting from said processing.

Claim 15

In a parallel computer system having at least a first primary task performing means (11), a second primary task performing means (21) and a first secondary task means (12), each of said task performing means (11,21) having a task performing memory means, and a message bus means (MB) interconnecting said task performing means (11,21), the method of transferring messages among said task performing means (11,21) comprising the steps of: sending n messages from said first primary task performing means (11) to said secondary primary task performing means (21), storing the count n of the messages sent, and said first secondary task performing means (12) starting processing upon failure of said first primary task performing means (11) but omitting the sending of the first n messages resulting from said processing.