Mechanism for providing virtual machines for use by multiple users

Abstract

According to one aspect of the invention, a request to generate a state checkpoint of a computer is initiated within a user-level software entity, such as a virtual machine. Upon sensing the request, a checkpointing mechanism generates and stores at least one checkpoint, each checkpoint comprising a representation of the total state of the computer system. Upon sensing a state restoration request corresponding to one of the checkpoints, the checkpointing mechanism restores the checkpointed state in the computer, which can then resume operation from the restored total state. According to another aspect of the invention, a total checkpointed state is exported to another computer, where the state can be modified, for example, debugged, and then loaded into either the originally checkpointed computer (which, again, may be a virtual machine), or some other computer.

1 . A method for allowing multiple users to share a common computer system image, the method comprising:
 generating a state vector representing the total machine state for a virtual machine configured with one or more commonly used applications;   establishing the state vector for the virtual machine as a read-only common computer system image for use by multiple users;   loading the state vector into a first virtual machine for use by a first user and into a second virtual machine for use by a second user; and   allowing the first user to use the first virtual machine and allowing the second user to use the second virtual machine, and allowing the first and second users to enter different data in the first and second virtual machines, respectively, so that the processing paths of the first and second virtual machines diverge.   
     
     
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