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Method and apparatus for synchronizing an imprecise time clock maintained by a computer system

  • US 6,023,769 A
  • Filed: 09/17/1998
  • Issued: 02/08/2000
  • Est. Priority Date: 09/17/1998
  • Status: Expired due to Term
First Claim
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1. A method of synchronizing a local clock maintained by a computer system, the method comprising:

  • in response to a transition of the local clock, calling a local timing routine for generating time readings at a precision greater than a precision of the local clock, to obtain a first time reading;

    requesting, from a remote server on a network, a second time reading corresponding to a current time and based on a server clock maintained by the remote server having a precision greater than the precision of the local clock;

    upon receiving the second time reading, calling the local timing routine to obtain a third time reading at a level of precision greater than the precision of the local clock;

    determining a delay associated with accessing the remote server based on the first and third time readings;

    adjusting the second time reading based on the delay;

    estimating, based on the adjusted second time reading, an amount of time until a next transition of the server clock at the level of precision of the local clock;

    after waiting for said amount of time, incrementing the adjusted second time reading by the least significant increment of the local clock; and

    setting the local clock based on the incremented adjusted second time reading.

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