Need of shift alteration in critical section problem?, Operating System

Assignment Help:

Explain with an example the need of Shift Alteration in critical section problem?

Consider processes Pi and Pj and consider the algorithm for Pi and Pj.

                           For Pi

                           do

   {

    while(turn!=i)

    critical section

    turn=j

    remainder section

   }whie(1);

 

For Pi

                           do

   {

    while(turn!=j)

    critical section

    turn=i

    remainder section

   }whie(1);

 

In the above code variable 'turn' is shared among the two processes. If turn=i after that process Pi is allowed to get into the critical section. This make sure that only one process at a time can be in its critical section. It doesn't satisfy the progress requirement and as a result we can do strict alteration with this code. That is if turn=0 and P1 is ready to get into the critical section, P1 can't enter into the critical section even though P0 may be in its remainder section. therefore a new algorithm which stores the state of the process is implemented. The code is:

do

{

  flag[i]=true

  while(flag[j])

  critical section

  flag[i]=false

  remainder section

}whiel(1)

 

   Here Pi is setting its flag as true. Then it confirms whether Pj is present in the critical section. If so after that it waits until the process Pj comes out of the critical section. If state of Pj is set as false after that Pi directly enters into the critical section.

 


Related Discussions:- Need of shift alteration in critical section problem?

Describe internal layout of the file system in windows 2000, Describe the i...

Describe the internal layout of the file system in windows 2000. The basic entity in NTFS is a volume and a volume is created by the Windows 2000 disk administrator utility and

How is memory management done using linked lists?, How is memory management...

How is memory management done using linked lists?   Each one node of the l list will have 4 fields as follows 1-this tells whether it s a hole or a process 2-starting ad

Os, why we say" OS is a resource allocator" and “OS is a control program"?

why we say" OS is a resource allocator" and “OS is a control program"?

Nachos file system, File System Interface and Implementation The Nachos ...

File System Interface and Implementation The Nachos file system, as distributed, uses a single-level index allocation method for data allocation of files. In the current design,

Bounded and unbounded buffer, Ask question #Minimum 100 difference between ...

Ask question #Minimum 100 difference between bounded and unbounded buffer words accepted#

Tcp and ip stack, What does the last four digits '0010' of the above dump r...

What does the last four digits '0010' of the above dump represent? What action will the Destination node takes when it receives this packet? The last four digits '0010' denotes

Benefits of virtual memory, Q.  When virtual memory is executed in a comput...

Q.  When virtual memory is executed in a computing system there are convinced costs associated with the technique and certain benefits. List the costs as well as the benefits. Is i

System call, how the system call is work?

how the system call is work?

Virtualization, What factors are involved in choosing the host operating sy...

What factors are involved in choosing the host operating system?

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