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

Hashed page table, Hashed page tables A common approach for handling ad...

Hashed page tables A common approach for handling address spaces larger than 32 bits is to use a hashed page table. Every entry in the hash table having a linked list of elemen

What is a file path name, What is a file path name? A list of the subdi...

What is a file path name? A list of the subdirectories, directories, and files we must traverse to reach a file from the root directory.

Virtualization, What factors are involved in choosing the host operating sy...

What factors are involved in choosing the host operating system?

What is a real-time system?, What is a Real-time system? A Real-time sy...

What is a Real-time system? A Real-time system is used when inflexible time requirements have placed on the operation of processor or the flow of data so it is often used as a

State the advantage of multiprocessor system, State the advantage of multip...

State the advantage of multiprocessor system? The advantages of multiprocessor system are:- a)      Enhanced throughput. b)      Economy of scale. c)       Enhanced re

Semantics for execution of rpcs, Q. Presume that a distributed system is su...

Q. Presume that a distributed system is susceptible to server failure. What mechanisms would be needed to guarantee the exactly once semantics for execution of RPCs? Ans

What do you mean by best fit, What do you mean by best fit? Best fit al...

What do you mean by best fit? Best fit allocates the smallest hole that is big sufficient. The entire list has to be searched, until it is sorted by size. This strategy creates

Explain the os/2 operating system, Explain the OS/2 Operating System Li...

Explain the OS/2 Operating System Like NetWare, OS/2 manage resources at three levels, as shown in Figure 4.5 Resources may be maintained at the session, process, and thread le

Define the global vs. local variables, Define the Global vs. local variable...

Define the Global vs. local variables It is also important to discuss the scope of resources being granted to the application program.  Variable scoping is defined as the acces

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