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

Define program preemption, Define Program preemption The Forced de-allo...

Define Program preemption The Forced de-allocation of the CPU from a program which is executing on the CPU is known as Program preemption

What is page fault and how to remove page fault?, What is page fault and wh...

What is page fault and what are the steps taken by the OS to remove page fault? A page fault is caused while a page that hasn't been brought into memory is being addressed. The

Define ageing, Define Ageing Ageing is a method of enhancing the priori...

Define Ageing Ageing is a method of enhancing the priority of process waiting in Queue for CPU allocation

How virtual memory is implemented, How Virtual memory is implemented Vi...

How Virtual memory is implemented Virtual memory can be implemented along with Segmentation and Paging

Palm os provides no signifies of concurrent processing, Q. Palm OS provides...

Q. Palm OS provides no signifies of concurrent processing. Discuss three major complications that concurrent processing adds to an operating system. Answer: a. A meth

What is the use of system programs, Q. What is the use of system programs? ...

Q. What is the use of system programs? Answer: System programs are able to be thought of as bundles of useful system calls. They provide fundamental functionality to users so

Define a policy for data storage, Produce a referenced four page report whi...

Produce a referenced four page report which describes the possible functionality of the system; similar systems that are out there and different possible approaches to delivering t

What is logical address space and physical address space, What is logical a...

What is logical address space and physical address space? The set of all logical addresses formed by a program is known as a logical address space; the set of all physical addr

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