Electrical computers and digital processing systems: multicomput – Multicomputer data transferring via shared memory
Reexamination Certificate
1998-10-09
2001-05-08
Maung, Zarni (Department: 2154)
Electrical computers and digital processing systems: multicomput
Multicomputer data transferring via shared memory
C709S216000
Reexamination Certificate
active
06230190
ABSTRACT:
BACKGROUND
The invention relates to scalable and fault-tolerant computer systems.
The need for fast, reliable and secure access to vast amounts of shared data worldwide has been driving the growth of multiprocessing paradigm in which applications, data storage, processing power, and other resources are distributed among a pool of processors. A number of architectures have been developed over time to address the requirements of multiprocessing. Depending on the resources that the processors share, multiprocessing architectures may be classified into three classes: share everything architecture, shared nothing architecture, and shared something architecture.
One example of a shared-everything architecture is a Symmetric Multiprocessing (SMP) architecture. An SMP system is capable of scaling multi-process or multi-threaded loads so that application code can run on any processor in the system without software changes. Adding new throughput to the SMP system may be as simple as adding a new CPU board, provided the operating system can take advantage of it. Implementations of SMP generally provide a plurality of CPU and memory boards which communicate with each other and with input/output boards over a wide and fast bus.
The SMP approach demands close communications between processors. The maintenance of consistency between processors is also non-trivial. The overhead and complexity of the consistency protocols may adversely affect the scalability of the SMP
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architecture. Further, processors in the SMP architecture typically share one copy of the operating system. In addition to limiting the scalability of the SMP architecture, the sharing of the copy of the operating system creates a potential for many single points of failure occurring when many resources are shared.
One commonly used technique to provide fault-tolerance (fail-over) depends on a client application to recognize when a server is unavailable to satisfy a request, and if so, either to locate another server or to deny the request altogether. For example, object techniques such as CORBA or Microsoft's Component Object Model (COM) and Distributed Component Object Model (DCOM) may be used to implement this technique. These object architectures require a one-to-one relationship between the client and the server. If the server fails for any reason, the client needs to handle the failure either by finding another server that can perform the same service or by handling an error condition. These approaches require complex and time-consuming communication set-ups to provide sufficient fault tolerance for applications.
Another system supporting fail-overs for server processes, available from Microsoft Corp. of Redmond, Washington, is called Microsoft Cluster Server (MSCS). The MSCS system uses a hot-standby technique in which a primary server and a standby server send “keep alive” messages back and forth so that the standby server is activated if it cannot contact the primary server. This is a time consuming fail-over process. Further, the system is inefficient since computer resources of the standby server are not used until a failure occurs.
SUMMARY OF THE INVENTION
A computer system has a plurality of processors, each processor executing an independent operating system image without sharing file system state information. The system includes an active backplane coupled to the plurality of processors; and one or more data storage devices coupled to the active backplane for satisfying data requests from the plurality of processors, each of the data storage devices being adapted to secure a file when one processor writes to the file and to release the file when the processor completes operation on the file.
Implementations of the invention include one or more of the following. The active back plane may be a switch. The switch may also be an Ethernet switch. Each data storage device may be a redundant array of inexpensive disk (RAID) device. Each data storage device may also be a network data storage device. A file sharing protocol may be supported by the processor and the data storage system. A means for locking a file may be provided on the data storage device. A byte range locking means may also be provided for controlling access to the data storage device. A cellular switch may be connected to the processors. Further, one or more applications selected from a group consisting of telephony applications, speech recognition applications, electronic mail applications, personal information management applications, and Web agent applications.
In a second aspect, a method for providing file storage in a computer system includes: executing on each processor of a plurality of processors an independent operating system image without sharing file system state information; communicating data over an active backplane coupled to the plurality of processors; and transferring data from one or more data storage devices coupled to the active backplane in satisfying data requests from the plurality of processors, each of the data storage devices being adapted to secure a file when one processor writes to the file and to release the file when the processor completes operation on the file.
Implementations of the invention include one or more of the following. The communicating step includes routing data using a switch, which may be an Ethernet switch. Data may be stored in a redundant array of inexpensive disk (RAID) device. The transferring step includes accessing one or more network data storage devices. Data may be communicated using file sharing protocol. A file on the data storage device may be locked, or alternatively, a byte range on the data storage device may be locked. Data may be received by a cellular switch connected to the processors. One or more applications may be executed on the system, the applications selected from a group consisting of telephony applications, speech recognition applications, electronic mail applications, personal information management applications, and Web agent applications. Additionally, the applications may be selected from a group consisting of facsimile applications, synchronization applications, short message system (SMS) delivery applications, and pager applications.
Advantages of the invention include the following. The invention provides scalability and fault tolerance. The invention allows many servers to perform the same task in an active/active scalable manner. The invention also supports load balancing among a pool of like servers. By providing a client process with access to a pool of like servers which are load balanced, the invention keeps the response time for each request to a minimum. Thus, the invention supports high data availability, fast access to shared data, and low administrative costs through data consolidation. Additionally, the invention may be built using standard off-the-shelf components to reduce overall system cost.
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“Serve
Chan Andy
Co Stephen
Doshi Priyen
Edmonds Paul
Tel Michael P.
Fish & Richardson P.C.
Maung Zarni
Openwave Systems Inc.
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