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

What is the cache coherency problem, Question: (a) Modern processors op...

Question: (a) Modern processors operate in one of two modes: one for the operating system and one for applications. What is the purpose of having these two modes? What are

Explain activities of an os in regard to file management, What are the five...

What are the five major activities of an operating system in regard to file management? The creation and deletion of files The creation and deletion of directories The s

Taxation problem, Smith, who is a civil engineer, purchased a 30-hectare bl...

Smith, who is a civil engineer, purchased a 30-hectare block of land in Australia in 1986 and used two hectares of it as a main residence. The part that was not main residence cost

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.

Design issues of network operating system, expalin about the design issues ...

expalin about the design issues of network operating system

Explain demand paging in virtual memory system, Question 1 Explain with di...

Question 1 Explain with diagram all possible states a process visits during the course of its execution Question 2 Discuss Inter-process Communication. What is critical-secti

How does dma raise system concurrency, Q. How does DMA raise system concurr...

Q. How does DMA raise system concurrency? How does it make difficult hardware design? Answer: DMA increases system concurrency by allowing the CPU to perform tasks while the

What is busy waiting?, What is busy waiting? When strict alteration is ...

What is busy waiting? When strict alteration is done there may take place situation like two processes setting their flag as true. Therefore both of the processes have equal pr

Shell scripting, A friend has promised to log in at a particular time. Howe...

A friend has promised to log in at a particular time. However, he needs to be contacted as soon as he logs in. The shell script checks after every minute whether he has logged in o

Can page tables be set up to replicate base registers, Q. We have an OS (o...

Q. We have an OS (operating system) for a machine that uses base and limit registers however we have modified the machine to provide a page table. Can the page tables be set up to

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