Tracking modified pages on a computer system
First Claim
1. A method for tracking modified pages in a system comprising a first computer system and a second computer system, the method comprising the steps of:
- copying, at a first point in time, a memory from the first computer system to the second computer system;
tracking, after the first point in time until a second point in time, a process that executes on the first computer system between the first point in time and the second point in time;
determining, from the process, after the second point in time, if a page of the memory was modified by the process; and
copying the page, if modified, from the first computer system to the second computer system.
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Accused Products
Abstract
A method for tracking modified pages is provided. The method is utilized in a fault-tolerant system, the fault-tolerant system comprising a first computer system and a second computer system. The method involves copying a memory from the first computer system to the second computer system at a first point in time. Between the first point in time and a second point in time, a scheduler tracks processes that execute on the first computer system in a harvest list. After the second point in time, the processes that made changes to the memory between the first and second points in time are retrieved. The changes to the memory are then copied to the second computer system and the changes are applied to the memory of the second computer system.
69 Citations
27 Claims
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1. A method for tracking modified pages in a system comprising a first computer system and a second computer system, the method comprising the steps of:
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copying, at a first point in time, a memory from the first computer system to the second computer system;
tracking, after the first point in time until a second point in time, a process that executes on the first computer system between the first point in time and the second point in time;
determining, from the process, after the second point in time, if a page of the memory was modified by the process; and
copying the page, if modified, from the first computer system to the second computer system. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An apparatus for tracking modified pages, the apparatus comprising:
a scheduler configured to;
begin tracking executing processes;
allocate an execution time slice of a processor to a process; and
store an identity of the process in a memory upon the process executing during the allocated execution time slice, wherein the memory is later traversed to determine which processes may have modified pages. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A system for tracking modified pages on a fault-tolerant system, the system comprising:
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a first and second computer system, each computer systems comprising;
a memory;
a communications port;
the first computer system further comprising;
a scheduler;
a monitor process in communication with the scheduler and the memory and communications port, the monitor process configured to;
copy, at a first point in time, the memory from the first computer system to the second computer system;
retrieve, from a harvest list provided by the scheduler, a process that executes on the first computer system between the first point in time and the second point in time;
retrieve from the process, after the second point in time, a change to the memory made by the process;
copy the change to the memory from the first computer system to the second computer system. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification