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

Multiprogramming, how response times are reduced by allowing time sharing o...

how response times are reduced by allowing time sharing on top of multiprogramming

Explain the performance of demand paging, Performance of demand paging ...

Performance of demand paging Demand paging can have an important effect on the performance of a computer system. As long as there are no page faults, the effective access time

Explain how indefinite blocking or starvation occur, explain how indefinit...

explain how indefinite blocking or starvation occurs..

Define dynamic linking, Define dynamic linking. Dynamic linking is same...

Define dynamic linking. Dynamic linking is same to dynamic loading, rather that loading being postponed unless execution time, linking is postponed. This feature is usually use

Direct memory access, A-  In a table format, compare between Programmed I/O...

A-  In a table format, compare between Programmed I/O, Interrupt -driven I/O, and Direct Memory Access (DMA) in terms of basic idea, Advantages, disadvantages, and the operating en

Define swapping, Define swapping. A process requires being in memory to...

Define swapping. A process requires being in memory to be executed. Though a process can be swapped temporarily out of memory to a backing store and then brought back into memo

Define maintaining data on a per client basis, Define Maintaining Data on a...

Define Maintaining Data on a Per Client Basis Perhaps the most dramatic syntactical programming change for the application developer of client – server applications is maintain

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?

Fibonacci sequence, #questionThe Fibonacci sequence is the series of number...

#questionThe Fibonacci sequence is the series of numbers 0,1,1,2,3,5,8,… Formally, it can be expressed as: fib0 = 0 fib1 = 1 fibn = fib n-1 + fib n-2 Write a C program u

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