Abstract: An automatic mutual exclusion computer programming system is disclosed which allows a programmer to produce concurrent programming code that is synchronized by default without the need to write any synchronization code. The programmer creates asynchronous methods which are not permitted make changes to shared memory that they cannot reverse, and can execute concurrently with other asynchronous methods. Changes to shared memory are committed if no other thread has accessed shared memory while the asynchronous method executed. Changes are reversed and the asynchronous method is re-executed if another thread has made changes to shared memory. The resulting program executes in a serialized order. A blocking system method is disclosed which causes the asynchronous method to re-execute until the blocking method's predicate results in an appropriate value. A yield system call is disclosed which divides asynchronous methods into atomic fragments.

Abstract: An automatic mutual exclusion computer programming system is disclosed which allows a programmer to produce concurrent programming code that is synchronized by default without the need to write any synchronization code. The programmer creates asynchronous methods which are not permitted make changes to shared memory that they cannot reverse, and can execute concurrently with other asynchronous methods. Changes to shared memory are committed if no other thread has accessed shared memory while the asynchronous method executed. Changes are reversed and the asynchronous method is re-executed if another thread has made changes to shared memory. The resulting program executes in a serialized order. A blocking system method is disclosed which causes the asynchronous method to re-execute until the blocking method's predicate results in an appropriate value. A yield system call is disclosed which divides asynchronous methods into atomic fragments.

Abstract: An automatic mutual exclusion computer programming system is disclosed which allows a programmer to produce concurrent programming code that is synchronized by default without the need to write any synchronization code. The programmer creates asynchronous methods which are not permitted make changes to shared memory that they cannot reverse, and can execute concurrently with other asynchronous methods. Changes to shared memory are committed if no other thread has accessed shared memory while the asynchronous method executed. Changes are reversed and the asynchronous method is re-executed if another thread has made changes to shared memory. The resulting program executes in a serialized order. A blocking system method is disclosed which causes the asynchronous method to re-execute until the blocking method's predicate results in an appropriate value. A yield system call is disclosed which divides asynchronous methods into atomic fragments.

Abstract: An automatic mutual exclusion computer programming system is disclosed which allows a programmer to produce concurrent programming code that is synchronized by default without the need to write any synchronization code. The programmer creates asynchronous methods which are not permitted make changes to shared memory that they cannot reverse, and can execute concurrently with other asynchronous methods. Changes to shared memory are committed if no other thread has accessed shared memory while the asynchronous method executed. Changes are reversed and the asynchronous method is re-executed if another thread has made changes to shared memory. The resulting program executes in a serialized order. A blocking system method is disclosed which causes the asynchronous method to re-execute until the blocking method's predicate results in an appropriate value. A yield system call is disclosed which divides asynchronous methods into atomic fragments.

Abstract: An automatic mutual exclusion computer programming system is disclosed which allows a programmer to produce concurrent programming code that is synchronized by default without the need to write any synchronization code. The programmer creates asynchronous methods which are not permitted make changes to shared memory that they cannot reverse, and can execute concurrently with other asynchronous methods. Changes to shared memory are committed if no other thread has accessed shared memory while the asynchronous method executed. Changes are reversed and the asynchronous method is re-executed if another thread has made changes to shared memory. The resulting program executes in a serialized order. A blocking system method is disclosed which causes the asynchronous method to re-execute until the blocking method's predicate results in an appropriate value. A yield system call is disclosed which divides asynchronous methods into atomic fragments.

Abstract: An automatic mutual exclusion computer programming system is disclosed which allows a programmer to produce concurrent programming code that is synchronized by default without the need to write any synchronization code. The programmer creates asynchronous methods which are not permitted make changes to shared memory that they cannot reverse, and can execute concurrently with other asynchronous methods. Changes to shared memory are committed if no other thread has accessed shared memory while the asynchronous method executed. Changes are reversed and the asynchronous method is re-executed if another thread has made changes to shared memory. The resulting program executes in a serialized order. A blocking system method is disclosed which causes the asynchronous method to re-execute until the blocking method's predicate results in an appropriate value. A yield system call is disclosed which divides asynchronous methods into atomic fragments.

Abstract: An automatic mutual exclusion computer programming system is disclosed which allows a programmer to produce concurrent programming code that is synchronized by default without the need to write any synchronization code. The programmer creates asynchronous methods which are not permitted make changes to shared memory that they cannot reverse, and can execute concurrently with other asynchronous methods. Changes to shared memory are committed if no other thread has accessed shared memory while the asynchronous method executed. Changes are reversed and the asynchronous method is re-executed if another thread has made changes to shared memory. The resulting program executes in a serialized order. A blocking system method is disclosed which causes the asynchronous method to re-execute until the blocking method's predicate results in an appropriate value. A yield system call is disclosed which divides asynchronous methods into atomic fragments.

Abstract: A subscription-based computing device has hardware and a subscription enforcer implemented in the hardware. The enforcer has an accumulator that accumulates a usage value as the computing device is being used and an expiration value register that stores an expiration value. The enforcer allows the computing device to operate in a subscription mode without hindrance and with full use when the usage value is less than the stored expiration value, and allows the computing device to operate in an expiration mode with hindrance and without full use when the usage value reaches the stored expiration value to signal that the subscription for the computing device has expired.

Abstract: Systems and methods are provided for resource access control in computer systems. Our approach includes new techniques for composing and authenticating principals in an access control system. Our principals may comprise information that identifies the role of the user of a computer system, the mechanism by which the user was authenticated, and program execution history. Thus, when a principal makes a request, access control determinations can be made based on the principal's identity. Access control lists may provide patterns that are used to recognize principals, thereby ensuring a level of security without enumerating precise identifiers for all of the possible principles that may request a particular resource.

Abstract: A method for backing up data in a plurality of computers connected via a network. The method includes forming partnerships between the plurality of computers such that each computer in a partnership commits under agreements to help backup the data of its partners. The method further includes periodically verifying that previously backed up data is being retained by the computers committed to act as backup partners in accordance with the agreements. In another embodiment, the method provides a distributed cooperative backing up of data in a system that includes a loose confederation of computers connected via a network. In this embodiment the method includes selecting computers as potential backup partners from among the loose confederation of computers connected via the network based on predetermined criteria, and negotiating a reciprocal backup partnership agreement between the computers based on predetermined requirements, including backup requirements.

Abstract: An automatic mutual exclusion computer programming system is disclosed which allows a programmer to produce concurrent programming code that is synchronized by default without the need to write any synchronization code. The programmer creates asynchronous methods which are not permitted make changes to shared memory that they cannot reverse, and can execute concurrently with other asynchronous methods. Changes to shared memory are committed if no other thread has accessed shared memory while the asynchronous method executed. Changes are reversed and the asynchronous method is re-executed if another thread has made changes to shared memory. The resulting program executes in a serialized order. A blocking system method is disclosed which causes the asynchronous method to re-execute until the blocking method's predicate results in an appropriate value. A yield system call is disclosed which divides asynchronous methods into atomic fragments.