Explain two level directory, Operating System

Assignment Help:

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 structure each user has a user file directory (UFD). The UFDs have an alike structure except each lists the files of a single user. As soon as a user starts or logs in the system's master file directory (MFD) is searched. The MFD is indexed by the account number or the user name and each entry points to the UFD for that user. Once a user searches for a particular file only his own UFD is searched and so different users may have the same names as long as all the file names within each UFD are unique.

A two level directory is able to be thought of as an inverted tree of height 2. The root of the tree is the MFD in addition to its descendents are the UFDs whose descendents are the files. 

Disadvantages:

            This structure detaches one user from the other. This is an benefit when the users are completely independent of each other but is a drawback when the users want to cooperate on some task and to access one another's files.

 

2000_Two Level Directory.png


Related Discussions:- Explain two level directory

What do you mean by semaphore?, What do you mean by semaphore?  Semap...

What do you mean by semaphore?  Semaphore : A synchronization variable that acquires on positive integer values. Invented by the Dijkstra P (semaphore): an atomic proce

Determine the value to be loaded in relocation register, Refer a program wi...

Refer a program with a linked origin of 5000. Suppose the memory area allocated to it have the start address of 70000. Determine the value to be loaded in relocation register?

Process creation, what is process creation and how to create a process

what is process creation and how to create a process

Determine the reasons for poor response time, Determine the reasons for Poo...

Determine the reasons for Poor response time Process busy or High I/O rates or High paging rates

What is belady anomaly, What is Belady's anomaly When plotting on a g...

What is Belady's anomaly When plotting on a graph the page faults versus the number of available frames. We notice that the number of faults for four frames is greater than th

Explain threads in details?, What are threads? A thread - sometimes c...

What are threads? A thread - sometimes called as an implementation context or a lightweight process - is a single sequential flow of control within a program. We use threads

What are the benefits of multiprogramming?, What are the benefits of multip...

What are the benefits of multiprogramming? Responsiveness : Multithreading is an interactive application may permit a program to continue running even if part of it is block

Programable clock modes in computer systems, Ask question #Minimuexplain th...

Ask question #Minimuexplain the programable clock modes in a computer system m 100 words accepted#

What is the concept of an atomic operation, Question: Concurrency and Sync...

Question: Concurrency and Synchronization a) Define the following terms: I. Critical section II. Mutual Exclusion III. Deadlock IV. Starvation. b) Name three methods w

What is cold backup, Cold Backup: It is copying the three groups of files...

Cold Backup: It is copying the three groups of files when the object is shut down. This is a straight file copy, generally from the storage disk directly to tape. You must end th

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