Formal semantics Sample Clauses

Formal semantics. This task is responsible for defining the formal semantics of the SELFMAN computational model. In our experience, it is essential to have a simple formal semantics when developing new abstractions (such as a computation model and architectural framework). This guarantees that there is no unexpected bad behavior. Two of the important questions that this workpackage will provide answers to are concurrency and communication. How will concurrency be managed between components: when should components be sequential and when should they be concurrent? How does this fit with the concurrency abilities of the underlying implementation platform? I.e., J2EE is built using Java and supports only coarse-grain concurrency (few threads). ▇▇▇▇▇▇ supports fine-grain concurrency (thousands of threads). For communication, we will determine to what degree the communication will be synchronous or asynchronous, and tightly coupled or loosely coupled. For example, we may use a tuple space abstraction, which allows components to communicate in a very loose fashion, where the source and destination components do not even know the identity of the other component. The main objective of this workpackage is to design and build a storage service on top of the service architecture of WP2 and the structured overlay network of WP1. The storage service will do replication (implemented over the structured overlay network), provide a transactional interface, and provide a simple database interface. The storage service will build on previous work by project partners: 1. The ZIBDMS database management system that is being developed by ZIB. 2. The experience in designing transaction protocols over structured overlay networks of KTH and UCL [MESA05]. The simple database interface is not intended to be a competitor to commercial databases (that would be impossible in a project of the size of SELFMAN) but to provide a proof-of-concept of a distributed database built on top of a structured overlay network. Such a distributed database does not yet exist and will be one of the contributions of SELFMAN. The storage service will support its own self management (node failure/removal/addition) using the primitives of WP2 and WP4. The storage service will enable the applications of WP5. Note that the storage service is an example of a realistic self-managing service built on top of the service architecture defined by WP1 and WP2. As such, the storage service will serve to validate this architecture even be...