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
Mobile device case with storage compartment
Preservation of liquid foods
Centralized behavioral information system
Compositions of quaternary ammonium compounds containing bioavailability enhancers
Methods of forming semiconductor devices having diffusion regions of reduced width
Apparatus and method for noise removal by spectral smoothing
Method for identifying modulators of GPCR GPR1 function
  Randomly Featured Patents
Process and intermediates for the preparation of 2,6-difluoroaniline
Method for moving object detection and hand gesture control method based on the method for moving object detection
Dynamically triggering notifications to human participants in an integrated content production process
Near field optical recording system having negative index of refraction structure
Method for the assembly of lead-acid batteries and associated apparatus
Method, system and apparatus for processing radiographic images of scanned objects
Accommodating intraocular lens with integral capsular bag ring
Packaging container
Film cassette having marker for identifying the exposure side of a medical radiograph
Flexible mount for hydraulic/pneumatic cylinder and the like