Explain banker''s algorithm, Operating System

Assignment Help:

Banker's Algorithm

In this analogy

Customers

processes

Units

resources, say, tape drive

Banker

Operating System

 

Customers

Used

Max

 

A
B
C
D

0
0
0
0

6
5
4
7

Available Units = 10

 

 

 

 

 

 

 

 


We observe four customers each of whom has been granted a number of credit nits. The banker reserved only 10 units somewhat than 22 units to service them. At definite moment the situation becomes

Customers

Used

Max

 

A
B
C
D

1
1
2
4

6
5
4
7

Available Units = 2

 

 

 

 

 

 

 

 

Safe State-    The key to a state being secure is that there is at least one way for all users to finish. In other analogy the state of is safe because with 2 units left, the banker is able to delay any request except C's, therefore letting C finish and release all four resources. With four units in hand the banker is able to let either D or B have the necessary units and so on.

Unsafe State-     Consider what would take place if a request from B for one more unit were granted

We would have following situation

Customers

Used

Max

 

A
B
C
D

1
2
2
4

6
5
4
7

Available Units = 1

 

 

 

 

 

Fig. 3

 

 

This is an unsafe state.

If all the customers namely A, B, C, and D request for their maximum loans, then banker couldn't satisfy any of them and we would have a deadlock.

It is significant to note that an unsafe state does not imply the existence or even the eventual existence a deadlock. What an unsafe state does involve is simply that some unfortunate sequence of events might lead to a deadlock. The Banker's algorithm is therefore to consider each request as it occurs and see if granting it leads to a safe state. If it does, the request is granted or else, it postponed until later.


Related Discussions:- Explain banker''s algorithm

What advantages are there to this two-level directory, What advantages are ...

What advantages are there to this two-level directory? Users are isolated from each other. Users have more freedom in choosing file names.

Determine the requiring variables on the scope of a thread, Determine the R...

Determine the Requiring Variables on the Scope of a Thread It is very common in server application programs to require variables on the scope of a thread. To provide such a sco

Buffer, What is bounded buffer

What is bounded buffer

What is independent process, What is independent process? A process is ...

What is independent process? A process is independent it cannot influence or be affected by the other processes implementing in the system. Any process does not share data with

Perform alpha-beta pruning on the following tree, Perform alpha-beta prunin...

Perform alpha-beta pruning on the following tree. Put an "X" over each node that is pruned. Put the final value next to all other nodes. Indicate which action MAX should take: to B

What are overlays?, What are over lays? If a large process enters which...

What are over lays? If a large process enters which is huge than the available memory we are able to use overlays. In this we can divide process into pieces .which is recognize

What is external fragmentation?, What is external fragmentation? As pro...

What is external fragmentation? As process are removed from and loaded to the memory free memory space is bracken into pieces .external fragmentation take place when enough mem

What disadvantages are there to this two-level directory, What disadvantage...

What disadvantages are there to this two-level directory? Without other provisions, two users who require cooperating with each other are hampered in reaching every other's fi

Write a short note on the linux file systems, Question: (a) Red Hat Li...

Question: (a) Red Hat Linux is distributed under the Open Source agreement. Explain what you understand by Open Source distribution system. (b) Write a short note on the L

Determine a policy that is not valid page replacement policy, Determine a p...

Determine a policy that is not a valid page replacement policy?  RU policy (Recurrently used) is not a valid page replacement policy.

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