Resources Contact Us Home
System and method for controlling client machine access to a portion of a file with a variable length

Image Number 7 for United States Patent #5175851.

A system and method in which client access to data at a server is synchronized to keep the data consistent by ensuring that each portion of the data accessible for modification at a node is not accessible for reading or modification by any other node, while allowing portions of the data accessible only for reading to be accessible by any number of nodes. If a conflicting request arises from a different client the server must revoke data that has been previously distributed to a client. For a revoke.sub.-- bytes request, all outstanding get.sub.-- bytes are marked so that the bytes that are being requested to be revoked will be discarded when they do arrive at the client. To insure that read and write system calls on a file are performed in a serializable fashion throughout a distributed environment, each machine at which a read is being performed must acquire a read token and each machine at which a write is being performed must acquire a read/write token from the server for the file. When any machine has a read/write token, no machine is allowed to have a read token, although any number of machines may have a read token at the same time. The server coordinates the distribution of these tokens by revoking all read tokens whenever a write token is requested and revoking the write token whenever any read token is requested.

  Recently Added Patents
Mesa-shaped piezoelectric resonator element
Signal generator
Processing data using information embedded in a data request
Automatically selecting a paper with increased dimensions than originally desired for printing and adding advertisement content to the increased dimensional area of the paper
End-of-session authentication
Pausing multimedia data streams
System and method for providing location and access network information support in a network environment
  Randomly Featured Patents
Replaceable gem stone setting for a jewelry piece
Image segmentation apparatus and method
Patient care system
Size for glass fibers
Method and apparatus for retrieving nearby data
Absorbent article having dual asymmetric leg elastics
Frequency standard
Athletic shoe midsole design and construction
Graphite intercalation compounds
Selection and use of lactic acid bacteria for reducing dental caries and bacteria causing dental caries