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

Explain next fit algorithm, NEXT FIT ALGORITHM Here scanning starts fro...

NEXT FIT ALGORITHM Here scanning starts from the first fit position and then it finds the next position which is large sufficient to hold the process. Thus the name next fit.

What are the three main activities of an operating system, What are the thr...

What are the three main activities of an operating system in regard to memory management? Keep track of which parts of memory are now being used and by whom. Decide which pr

Research proposal, what topic i choose for os research proposal

what topic i choose for os research proposal

Explain the application interaction protocols, Explain the Application Inte...

Explain the Application Interaction Protocols Application interaction protocols are uniquely defined for each program and are used to logically describe the data being passed b

Explain disk scheduling algorithms-shortest seek time first, SSTF (Shortest...

SSTF (Shortest Seek Time First) After a demand go to the closest request in the work queue regardless of direction Decrease total seek time compared to FCFS Disadv

Explain about deadlock prevention, Explain about deadlock prevention? I...

Explain about deadlock prevention? In order for the occurrence of deadlock, the four conditions like mutual exclusion, hold and wait, no pre-emption and  circular wait must hap

What is a resource-allocation graph, What is a resource-allocation graph? ...

What is a resource-allocation graph? Deadlocks can be explained more precisely in terms of a directed graph called a system resource allocation graph. This graph having of a se

How does an operating system make multiprogramming possible, How does an op...

How does an operating system make multiprogramming possible by using single processor?

Explain lru page replacement in detail, LRU page replacement In least ...

LRU page replacement In least lately used page replacement algorithm we will replace that page that hasn't been used for the longest period of time. This is similar as an opti

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