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

Name two differences between logical and physical addresses, Q. Name two di...

Q. Name two differences between logical and physical addresses? Answer: A logical address doesn't refer to an actual existing address rather it refers to an abstract address in

What is demand paging, What is Demand paging? Virtual memory is commonl...

What is Demand paging? Virtual memory is commonly executed by demand paging. In demand paging, the pager brings only those essential pages into memory instead of swapping in a

What is an operating system?, What is an operating system? An operating...

What is an operating system? An operating system is a program that acts as a mediator between a user and the computer hardware. The function of an operating system is to provid

Difference between internal and external fragmentation, Explain the differe...

Explain the difference between internal and external fragmentation. Internal Fragmentation is the area in a region or a page that is not used by the job occupying that region o

Explai basic concepts of demand paging, Basic concepts When a process i...

Basic concepts When a process is to be changed in, the pager guesses which pages will be used before the process is changed out again. Instead of swapping in a entire process,

Explain the reasons why an organisation fail to plan, Problem 1: (a) Wh...

Problem 1: (a) What are the likely benefits which an organisation may derive from the planning process? (b) Explain the main reasons why an organisation may fail to plan.

Write a note on threads, Question 1 Explain (a) tightly coupled systems   ...

Question 1 Explain (a) tightly coupled systems                               (b) Loosely coupled system Question 2 Describe the RPC model Question 3 Write a note o

Explain variable partitioning technique, VARIABLE PARTITIONING We can d...

VARIABLE PARTITIONING We can differ the partitions and change the location according to the size of the process. Here if a 10k process enters we are able to make a space of

Determine the minimum number of units of resource, An operating system invo...

An operating system involves 3 user processes each one requiring 2 units of resource R .The minimum number of units of R like no deadlocks will ever take place is The minimum

Explain two level directory, Two Level Directory This kind of structure...

Two Level Directory This kind of structure overcomes the problems of assigning unique names to the files. Thus there need not be any confusion among users. In this kind of s

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