Abstract: Techniques are described for managing execution of programs on multiple computing systems, such as based at least in part of user-specified constraints. For example, constraints related to execution of a program may be based on a desired relative location of a host computing system to execute a copy of the program with respect to an indicated target (e.g., computing systems executing other copies of the program or copies of another indicated program), on particular geographic locations, and/or on factors not based on location (e.g., cost of use of a particular computing system, capabilities available from a particular computing system, etc.). Some or all of the multiple computing systems may be part of a program execution service for executing multiple programs on behalf of multiple users, and each may provide multiple virtual machines that are each capable of executing one or more programs for one or more users.

Abstract: A distributed, web-services based storage system. A system may include a web services interface configured to receive, according to a web services protocol, a given client request for access to a given data object, the request including a key value corresponding to the object. The system may also include storage nodes configured to store replicas of the objects, where each replica is accessible via a respective unique locator value, and a keymap instance configured to store a respective keymap entry for each object. For the given object, the respective keymap entry includes the key value and each locator value corresponding to replicas of the object. A coordinator may receive the given client request from the web services interface, responsively access the keymap instance to identify locator values corresponding to the key value and, for a particular locator value, retrieve a corresponding replica from a corresponding storage node.

Abstract: Techniques are described for facilitating interactions between computing systems, such as via a third-party transaction authorization system that automatically authorizes transactions between parties. In some situations, the transactions are programmatic transactions involving the use of fee-based Web services by executing application programs, with the transaction authorization system authorizing and/or providing payments for transactions between Web service provider and consumer parties in accordance with private authorization instructions previously specified by the parties. The authorization instructions may include predefined instruction rule sets that regulate conditions under which a potential transaction can be authorized, with the instruction rule sets each referenced by an associated reference token.

Abstract: Techniques are described for facilitating interactions between computing systems, such as by performing transactions between parties that are automatically authorized via a third-party transaction authorization system. In some situations, the transactions are programmatic transactions involving the use of fee-based Web services by executing application programs, with the transaction authorization system authorizing and/or providing payments in accordance with private authorization instructions previously specified by the parties. The authorization instructions may include predefined instruction rule sets that regulate conditions under which a potential transaction can be authorized, with the instruction rule sets each referenced by an associated reference token.

Abstract: Techniques are described for facilitating interactions between computing systems, such as by performing transactions between parties that are automatically authorized via a third-party transaction authorization system. In some situations, the transactions are programmatic transactions involving the use of fee-based Web services by executing application programs, with the transaction authorization system authorizing and/or providing payments in accordance with private authorization instructions previously specified by the parties. The authorization instructions may include predefined instruction rule sets that regulate conditions under which a potential transaction can be authorized, with the instruction rule sets each referenced by an associated reference token.