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 is meant by demand paging? explain, What is meant by demand paging? Ex...

What is meant by demand paging? Explain. Demand paging is a technique to implement virtual memory. In demand paging simply when a page is required it is brought into memory. As

Removing system dependencies, Removing System Dependencies Because port...

Removing System Dependencies Because portions of the client - server application program may execute on different machines, it is very important for the developer to remove the

How can a user program disturb the normal operation, How can a user program...

How can a user program disturb the normal operation of the system? a) Issuing illegal I/O operation. b) By accessing memory locations within the OS itself. c) Refusing to

Independent process, what is independent process? distinguished between ind...

what is independent process? distinguished between independent process and co-operating process

Briefly discuss on page replacement, Briefly discuss on page replacement? ...

Briefly discuss on page replacement? Page replacement approach is fixed as follows. If no frame is free, we search one that is not presently being used and free it. We can fre

Explain three major components of page-fault service time, We are faced wit...

We are faced with three major components of the page-fault service time. 1. Service the page-fault interrupts. 2. Read in the page. 3. Restart the processes.

Explain how the system can deal with the starvation problem, Q. Can a syste...

Q. Can a system detect that some of its processes are starving? If you answer "yes," explain how it can. If you answer "no," explain how the system can deal with the starvation pro

Identify main functions of an operating system, Question: Introduction to ...

Question: Introduction to Operating Systems a) Define the term ‘Operating System' and identify main functions of an operating system. b) What are the characteristics of a go

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