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 a path name, What is a path name? A pathname is the path from t...

What is a path name? A pathname is the path from the root by all subdirectories to a specified file. In a two-level directory structure a user name and a file name explain a pa

Reference counting, The idea of reference counting is to maintain, for ever...

The idea of reference counting is to maintain, for every object, the total number of references to that object, i.e. the number of "incoming" pointers. Whenever the number of refer

Concepts of an address - data and control bus, Let us consider the operatio...

Let us consider the operation of the EPROM device in more detail. Consider the pining details below again   Before we examine the interface means of the EPROM, it is worth

Describes attributes, What are attributes? Attributes are the one, whic...

What are attributes? Attributes are the one, which explains the properties of data object.

Catalogue the design goals of windows xp, Q. Catalogue the design goals of ...

Q. Catalogue the design goals of Windows XP. Answer: Design goals comprise security and reliability and Windows and POSIX application compatibility with high performance and ex

What is a semaphore, Question 1: a) State the different file attribute...

Question 1: a) State the different file attributes and briefly explain the operations that can be performed on each files. b) What is a semaphore? Describe why it is impor

System service program, System Service Program system service program S...

System Service Program system service program Supports and provides the services for other program. System service program perform Varity of tasks.  They are further divided in

Is data in a file access sequentially or randomly, Q. Give an instance of ...

Q. Give an instance of an application in which data in a file should be accessed in the following order: a. Sequentially b. Randomly Answer: a. Print the content of

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