Tugas Sistem Terdistribusi

Nama : Yeremia Ayunda Christine
NPM  : 17112805
Kelas  : 4KA01

Exercise 2.11

Consider a simple server that carries out client requests without accessing other servers. Explain why it is generally not possible to set a limit on the time taken by such a server to respond to a client request. What would need to be done to make the server able to execute requests within a bounded time? Is this a practical option?  

Answer :

We cannot send a limit for the time taken by a server to respond a client request because the arrival of client requests is not predictable For example we can have limits for executing a computation corresponding to a request but we can not predict how much a request will have to wait until it's execution time arrives If the server uses threads there is not possible for the server to allocate sucient time to a particular request within any given time limit If the requests are carried out one at a time they may wait in the queue for an unlimited amount of time .

We can imagine the following solution trying to set a time limit in responding to client requests :

• we can limit the number of clients to suit the server capacity to deal with many clients we should use a server with a higher capacity many processors .
• we can replicate the service

The practicability of our solutions :

• setting a limit for the number of clients that are able to suit the service we of er induces the lost of some client requests
• the introduction of replicas brings the problem of keeping them consistent . This requires also an amount of time that could be used for responding client requests