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

Describe two segment-replacement algorithms, Q. Segmentation is alike to p...

Q. Segmentation is alike to paging but uses variable-sized "pages". Describe two segment-replacement algorithms based on FIFO and LRU page replacement schemes. Remember that since

Identifying parallelism, Identifying parallelism A formal way to identi...

Identifying parallelism A formal way to identify parallelism in an activity is to draw a task dependence graph in a directed graph in which each vertex represents a task to

Define properties of distributed operating system, Define properties of Dis...

Define properties of Distributed operating system Distributed:- This system distributes computation among several physical processors. The processors do not share memory or a

What is banker''s algorithm, What is banker's algorithm? Banker's algor...

What is banker's algorithm? Banker's algorithm is a deadlock avoidance algorithm that is applicable to a resource-allocation system with multiple examples of each resource type

Deadlock, Suppose we have 3 processes running at the same time as shown in ...

Suppose we have 3 processes running at the same time as shown in the following table. Each resource only has one instance. Show a possible scenario of resource allocation that r

Vehicle tasks using semaphores, Gopher Gallery consists of a shopping mall ...

Gopher Gallery consists of a shopping mall and a cart ride that covers  the 150 acre habitat. There are m visitors and n single-person vehicles. Visitors  stroll around the mall at

Gang scheduling , Gang Scheduling : A set of related process is scheduled ...

Gang Scheduling : A set of related process is scheduled to execute on a set of processors at the similar time, on a 1-to-1 basis. Closely related processes or threads may be sched

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

Banker''s algorithm, Consider the following snapshot of a system, answer th...

Consider the following snapshot of a system, answer the following questions using the banker's algorithm: 1. What is the content of the matrix Need? Is the system in a safe stat

Describe the technique of packing, Describe the technique of packing. T...

Describe the technique of packing. The physical record size will not accurately match the length of the desired logical record and the Logical records may even differ in length

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