Recall that group communication provides a model of communication whereby a process can send a single message to a group of other processes. When such a message is sent to a predefined group of recipients (as opposed to all nodes on the network), we refer to the communication as multicast. Since a multicast is sent out to a specific group, it is important to have agreement on the membership of ...

In a distributed file system (DFS), multiple clients share files provided by a shared file system. In the DFS paradigm communication between processes is done using these shared files. Although this is similar to the DSM and distributed object paradigms (in that communication is abstracted by shared resources) a major difference between these paradigms and the DFS paradigm is that the resources...

In previous lectures we’ve mentioned that one of the reasons that distributed systems are different (and more complicated) than nondistributed systems is due to partial failure of system components. We’ve mentioned that dependability is an important challenge in designing and building distributed systems and that the presence of failure often makes achieving transparency (e.g., for RPC) difficu...

An important aspect of dependability in distributed systems relates to security. There are two security related aspects of dependability: confidentiality and integrity. In a system that offers confidentiality, information will only be disclosed to (and services will only be provided to) authorised parties. A system that provides integrity will ensure that alterations (to data or services) can o...

This lecture deals with one of the fundamental issues encountered when constructing a system made up of independent communicating processes: dealing with time and making sure that processes do the right thing at the right time. In essence this comes down to allowing processes to synchronise and coordinate their actions. Coordination refers to coordinating the actions of separate processes relat...

This lecture deals with one of the fundamental issues encountered when constructing a system made up of independent communicating processes: dealing with time and making sure that processes do the right thing at the right time. In essence this comes down to allowing processes to synchronise and coordinate their actions. Coordination refers to coordinating the actions of separate processes relat...

• A graph G is an ordered pair (V,E) consisting of a set V of vertices and a set E (disjoint from V ) of edges, together with an incidence function End : E → M2(V ), where M2(V ) is set of all 2-element sub-multisets of V . We usually write V = V (G), E = E(G), and End = EndG. • If e is an edge and u, v are vertices such that End(e) = {u, v}, we say that e joins u and v, or, u and v are inciden...

This lecture deals with one of the fundamental issues encountered when constructing a system made up of independent communicating processes: dealing with time and making sure that processes do the right thing at the right time. In essence this comes down to allowing processes to synchronise and coordinate their actions. Coordination refers to coordinating the actions of separate processes relat...

These are lecture notes for the class Stochastic Calculus offered at the Courant Institute in the Fall Semester of 2012. It is a graduate level class. Students should have a solid background in probability and linear algebra. The topic selection is guided in part by the needs of our MS program in Mathematics in Finance. But it is not focused entirely on the Black Scholes theory of derivative pr...