Spring 2009 CIS 455 555 Internet and Web Systems Final Examination 120 minutes 7 questions 120 pts Try to allocate no more than 1 minute per point and be concise with your answers Your name 1 Suppose 3 years from now we have a ne w 4G cell phone and wish to use it as as a Twitter like server we publish our GPS location and an occasional tweet like message What role should replication play in keeping this service available and which type of consistency should be used on the replica s 20pts 2 Suppose we want to provide Web Services over a distributed hash table like Pastry Explain how this can be done including messaging at both the RPC layer and the interface definition layer 15pts 3 a Which of the ACID properties does two phase commit address and how 3 pts b Which of the ACID prope rties does two phase locking address and how 3 pts c What is the role of logging in ensuring ACID properties 4 pts 4 Outline the steps for taking a keyword query of the form k1 k2 and producing ranked results in a partitioned architecture like that of Google or your crawler In particular note that k1 and k2 may be indexed at different nodes 20pts 5 Write the map and re duce functions that given a distributed log of document requests each request of the form GET doc URL count the numbe r of references to index html 15pts 6 Outline the roles of the parties nodes and of cryptography in the SSL protocol What does each node do and how does it employ cryptography to ensure authe ntication 20pts 7 Given an XML version of an inverted index over English docume nts inve rted xml of the form index word text text id id word entry wordId wordId foundInDocId foundInDocId entry index and an XML version of the term frequencies docFreq doc id id word id id count count word doc docFreq Write an XQuery that returns for the word exam all document occurrences and term frequencies Your output should have the following format occurrences document docId docId count count document occurrences 20pts