1DT066 Distributed Information SystemsHomework 21)This is a generalquestionon distributed systems.a)With examples describe Access, Location and Migration transparency in adistributed system.b)With examples describe what Middleware is.c)With examplesdescribe the client server model?d)What is redundancy and why is it used in a distributed system.2)This is a question on remote procedure call.a)What are Client and Server Stubs and how are they used in remoteprocedure calls?b)When passing data values between different machines with differentoperating systems what problems have to be solved?c)When calling a remote procedure or method where a reference parameteris passed, what problems have to be solved and how are they solved?3)Consider the events of processes P1, P2 and P3 in the following figure:L(e): denotes the Lamport timestamp of event e.V(e): denotes the Vector timestamp of event e.a)Write down the Lamport timestampsin the above figure.b)Write down the Vector timestampsin the above figure.c)Can the order of Lamport timestamps infer the order of events? In otherwords, if L(e) < L(e’), can we infer that eàe’ in Lamport timestamps?d)Similarly, if V(e) < V(e’), can we infer that eàe’ in Vector timestamps?4)Consider a server provides theReadandWriteoperations for its clients to anumber of objectsM1, M2, ... , Mn:Read(i)returns the value of objectMi.Write(i, Num)assignsNumto objectMi.There are two transactions A and B defined as follows:A:x=Read(j); y=Read(i); Write(j,4),Write(i,3);B:x=Read(k); Write(i,5); y=Read(j); Write(k,6).Give three serially equivalent interleavings of the transactions A and B.5)a)What duties does the ‘link layer’ have in an standard network stack?Describe at least 3 points.b)When considering Medium Access Control, describe an advantage and adisadvantageof “Channel Partitioning” approaches compared to “RandomAccess” approaches.c)With“Random Access”approaches, if nodes listen to the medium toensure it is free before transmitting data, how can collisions still occur?6)a) Acomputer program wants to load a file from the hard disk into memory.Describe at least 4 steps that occur during this process.b) The file has been loaded to memory.At some point in its operation, theprogram wants to have the first byte fromthe file in its CPU. Describe at least4 operations that will be performed before the byte can bemanipulatedin theCPU.7) a)What is the difference between two-phase locking and two-phasecommit? Howdoes two-phase locking prevent inconsistent analysis?b)Which transactional property is enforced by distributed commitprotocols? Explain briefly.Please submit your personal answers electronically toby 15:00 Dec 9th