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

Give an overview of unix based file systems, Give an overview of UNIX based...

Give an overview of UNIX based file systems. UNIX and UNIX-like operating systems allocate a device name to each device, other than this isn't how the files on that device are

Explaintable management techniques, Discuss in detail Table management Tech...

Discuss in detail Table management Techniques?     An Assembler employs the subsequent tables: OPTAB: Operation Code Table consists of mnemonic operation code and its machi

How can an index file be used to speed up, How can an index file be used to...

How can an index file be used to speed up the access in direct-access files? Have an index in memory; the index gives the key and the disk location of its corresponding record.

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

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

Explain interrupts, Interrupts The hardware mechanism that enables a de...

Interrupts The hardware mechanism that enables a device to inform the CPU is called an interrupt. The basic interrupt mechanism works as follows. The CPU hardware has a wire kn

Under what circumstances do page faults occur, Under what circumstances do ...

Under what circumstances do page faults occur?  Describe the actions taken by the operating system when a page fault occurs. A page fault happens when an access to a page that

Define most common phase structured grammar, Which is most common phase str...

Which is most common phase structured grammar? Most common phase structured grammar is Context – Sensitive

Business, why some companies do not pay sufficient attention to staff induc...

why some companies do not pay sufficient attention to staff induction

What happens when you high-level format a floppy disk, Question: a. The...

Question: a. The following questions refer to a generic Windows file system: i) Describe what happens when you high-level format a floppy disk? ii) What is the maximum size

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