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File backup system

  • US 5,060,185 A
  • Filed: 02/27/1989
  • Issued: 10/22/1991
  • Est. Priority Date: 03/25/1988
  • Status: Expired due to Fees
First Claim
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1. A file backup system comprising amaster device and a plurality of satellite devices positioned for inputting sales information on sold goods, and aplurality of file devices including point of sale data files and file control sections for retrieving and for updating said point of sale data files and to provide an up-to-date state of said data files in response to a request from said master device or any of said satellite devices and to control data communication with said master device or with any of said satellite devices during operation of the system, said plurality of file devices being coupled with each other such that any one of said file devices operates as a main file device to control file retrieving and updating operations and data communication within the system and to control the updating of said point of sale data files of the remaining file devices and any one of said remaining file devices operates as a main file device when said main file device has failed, and said main file device being coupled with said remaining file devices such that, when said point of sale data file of one of said remaining file devices is destroyed, said main file device retrieves said one of said remaining file devices and while updating the data file therein is responsive to a request from one of said master or satellite devices to transmit updated data to one of said master or satellite devices and then recopies the updated data contents from its own file to said point of sale data file that failed in the up-to-date state while at the same time performing normal file retrieving and updating operations and controlling operation of the data communication.

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