EP0092895A2
Expired / Lapsed
EP
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Data processing system
Assignee: Fujitsu Services Ltd
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Filing: 1983-02-02
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Granted: —
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Expires: 2003-02-02
Abstract
Abstract A data processing system comprising multiple processing nodes (10) each containing a processor (14) and a data store (15). The store holds local data, and also holds copies of shared data required by the node. This reduces conflict between the nodes in accessing the shared data. When one node updates the shared data, it sends an update message to all the other nodes over a transmission link (11). The processor is then free to continue processing. When the message reaches the other nodes, it updates the other copies of the shared data, so as to ensure consistency. Each node receives messages from the link in the same order, and this defines a unique chronological order for the updates, even though the nodes are asynchronous. A node is temporarily suspended if an update occurs out of this correct chronological order.
Inventors
- 👤 Nigel Llewelyn Vince
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 07:28
CPC Classifications
G; G06; G06F; G06F15/00; G06F15/16; G06F15/163; G06F15/173; G06F15/17337
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
179 words
A data processing system comprising a plurality of processing nodes (10) interconnected by at least one data transmission link (11), each node comprising: (a) a data store (15) holding local data items unique to that node and also holding shared data items copies of which are also held in at least one other node, and (b) a data processor (14) capable of reading and updating data items in the data store, characterised in that: (a) whenever the processor (14) in one node updates a shared data item, the node (10) generates a message containing the updated value of the item and its address and transmits the message over the link (11) to the other nodes (10), the processor being capable of continuing with its processing without waiting for the message to reach the other nodes, and (b) when the message is received by the other nodes it is used to update the copies of the shared data item held in the stores (15) of those nodes, thereby ensuring that all copies of the shared data item are kept consistent.
Claim 2
Dependent Claim
179 words
A data processing system comprising a plurality of processing nodes (10) interconnected by at least one data transmission link (11), each node comprising: (a) a data store (15) holding local data items unique to that node and also holding shared data items copies of which are also held in at least one other node, and (b) a data processor (14) capable of reading and updating data items in the data store, characterised in that: (a) whenever the processor (14) in one node updates a shared data item, the node (10) generates a message containing the updated value of the item and its address and transmits the message over the link (11) to the other nodes (10), the processor being capable of continuing with its processing without waiting for the message to reach the other nodes, and (b) when the message is received by the other nodes it is used to update the copies of the shared data item held in the stores (15) of those nodes, thereby ensuring that all copies of the shared data item are kept consistent.
Claim 3
Dependent Claim
25 words
A system according to Claim 1 wherein each node includes a first-in first-out buffer for holding a queue of messages awaiting transmission over the link.
Claim 4
Dependent Claim
52 words
A system according to Claim 2 wherein each node includes means for counting the number of messages it has generated which have not yet been transmitted, and means for temporarily suspending operation of the node whenever a message is received from another node while said number of messages is greater than zero.
Claim 5
Dependent Claim
58 words
A system according to Claim 3 wherein the data transmission link comprises a ring network, and wherein the means for counting comprises a counter which is incremented by one whenever a message is placed in the buffer, and decremented by one whenever a message is received which originated at the same node, having travelled completely round the ring.
Claim 6
Independent Claim
27 words
A system according to any preceding claim wherein the transmission link is such that all the nodes receive the messages from the link in the same sequence.
Claim 7
Dependent Claim
27 words
A system according to Claim 5 wherein the transmission link comprises a ring network in which only one message at a time is present on the link.
Claim 8
Independent Claim
36 words
A system according to any preceding claim wherein the address contained in each said message is the virtual address of the data item, each node identifying the same shared data item by the same virtual address.
Claim 9
Dependent Claim
35 words
A system according to Claim 7 wherein each node includes an address translation unit for translating said virtual address into a real address identifying the physical location of the data item in the data store.
Claim 10
Dependent Claim
35 words
A system according to Claim 8 wherein the address translation unit, whenever it translates the virtual address of a data item, also produces a signal indicating whether that data item is a shared data item.
Claim 11
Independent Claim
37 words
A system according to any preceding claim in which the shared data consists of a plurality of independent areas and wherein the nodes are interconnected by a plurality of data transmission links, one for each said area.
References Cited (Backward Citations)
No citation records indexed.
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