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 co-operating scheduling?, What is co-operating scheduling? CPU ...

What is co-operating scheduling? CPU scheduling decisions may possibly place under the following four circumstances: 1.      When process switches from the running state to

What is meant by context switch, What is meant by context switch? Switc...

What is meant by context switch? Switching the CPU to another process needs saving the state of the old process and loading the saved state for the latest process. This task is

Define logical address and physical address, Define logical address and phy...

Define logical address and physical address. An address formed by the CPU is referred as logical address. An address seen by the memory unit that is the single loaded into the

Explain linked list allocation using index, Linked list allocation using in...

Linked list allocation using index The blocks don't have a fixed size. Pointers are utilized to point to the next block in a file. The pointers are set aside as a separate tabl

Dual mode operation, WHAT ARE THE ADVANTAGES AND DISADVANTAGES OF DUAL MODE...

WHAT ARE THE ADVANTAGES AND DISADVANTAGES OF DUAL MODE OPERATION OF OPERATING SYSTEM>?

What is the main problem with the fcfs scheme, Question : a) Consider ...

Question : a) Consider table 1.0 below, assume the processes arrived in the order P 1 , P 2 , P 3 , P 4 at time shown and need the indicated burst time (both in milliseconds)

Name two differences between logical and physical addresses, Q. Name two di...

Q. Name two differences between logical and physical addresses? Answer: A logical address doesn't refer to an actual existing address rather it refers to an abstract address in

What is the use of the command interpreter, Q. What is the use of the comma...

Q. What is the use of the command interpreter? Why is it generally separate from the kernel? Answer: It reads commands from the user or else from a file of commands and execu

Managing outside communication, Problem: Managing Outside Communication...

Problem: Managing Outside Communication. a. What is the principal action we use when communicating through a web browser? b. Give an example of how to preaddress an email

Replacement algorithm for tlb, Consider the following C program where M, N,...

Consider the following C program where M, N, K are predefined constants. Assume int is 4 bytes. Suppose this program is run on a machine with 4KB page size and 32 TLB entries. Init

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