What inference does recovery in distributed systems, Operating System

Assignment Help:

Q. Consider a distributed system with two sites A and B. Consider whether site A can distinguish among the following:

a. B goes down.

b. The link between A and B goes down.

c. B is much overloaded and its response time is 100 times longer than normal.

What inference does your answer have for recovery in distributed systems?

Answer: One technique would be for B to at regular intervals send an I-am-up message to a indicating it is still alive. If A doesn't receive an I-am-up message it can assume either B-or the network link-is down.

Note that an I-am-up message doesn't permit A to distinguish between each type of failure. One technique that permits A better to determine if the network is down is to send an Are-you-up message to B using an exchange route. If it obtains a reply it can determine that indeed the network link is down and that B is up.

If we presume that A knows B is up and is reachable (via the I-am-up mechanism) in addition to that A has some value N that indicates a normal response time A could monitor the response time from B and compare values to N permitting A to determine if B is overloaded or not.

The inferences of both of these techniques are that A could choose another host-say C-in the system if B is either down or unreachable and or overloaded.


Related Discussions:- What inference does recovery in distributed systems

Explain doscreatethread functions used in the os/2, Explain DosCreateThread...

Explain DosCreateThread Functions Used in the OS/2  DosCreateThread(&threadID,MyThreadFunction,arg,flags,stackSize) DosCreateThread creates a thread within the context of th

Software Support (Introducing Operating Systems), The questions ask List fo...

The questions ask List four major functions of an OS. My answer: Function 1: Provide a user interface Function 2: Manage files Function 3: Manage hardware Function 4: Manage appli

Use of c and c++, One reason to learn C and C++ is simply that so much soft...

One reason to learn C and C++ is simply that so much software is written in these languages. A related, butmore fundamental reason, is that C and C++ are relatively low-level, allo

Any four types of operating system feature and structure, explain any four...

explain any four types of operating system feature and structure(design)

What is critical section?, What is critical section? Every process has ...

What is critical section? Every process has a segment code called the critical section, in which the process may be updating tables, changing variables, writing file and etc. W

What are two probable uses of these multiple modes, Q. Several CPUs provide...

Q. Several CPUs provide for more than two modes of operation. What are two probable uses of these multiple modes? Answer: Although most systems merely distinguish between use

Explain fifo page replacement, Explain FIFO page replacement A FIFO rep...

Explain FIFO page replacement A FIFO replacement algorithm associates with every page the time when that page was brought into memory. When a page must be changed, the oldest p

Explain the alphabet and string, Explain the Alphabet and String A fini...

Explain the Alphabet and String A finite set of symbols is known as alphabet. An alphabet is frequently denoted by sigma, yet can be given any name. B = {0, 1} says B is an

Differences among user-level threads and kernel-level thread, Q. What are t...

Q. What are two differences among user-level threads and kernel-level threads? Under what situations is one type better than the other? Answer: (1) User-level threads are un

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd