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

Write an equation for this seek time, Q. The accelerating search for descr...

Q. The accelerating search for described in subsequent exercise is typical of hard-disk drives. By contrast floppy disks and several hard disks manufactured before the mid-1980s t

What is a general graph, What is a general graph? A tree structure wher...

What is a general graph? A tree structure where links can go from one branch to a node earlier in the similar branch or other branch, allowing cycles.

What are batch systems?, What are batch systems? Early computers were p...

What are batch systems? Early computers were physically huge machines run from a console. The general input devices were card readers and tape drivers. The common output device

Explain the circumstances under which os use mutexes, Q. Give the reasons ...

Q. Give the reasons why Windows XP, Solaris and Linux implement multiple locking mechanisms. Explain the circumstances under which they use mutexes, spinlocks, semaphores, adaptiv

Plot a function for value of heights, The performance of a file system depe...

The performance of a file system depends upon the cache hit rate (fraction of blocks found in the cache). If it takes 1 msec to satisfy a request from the cache, but 40 msec to sat

What is the basic function of assembler, Q. What is the basic function of A...

Q. What is the basic function of Assembler ? Input to an assembler is an assembly language program. Output is an object program and information which enables the loader to prep

Why system calls have to be implementing by a interpreter, Q. What system c...

Q. What system calls have to be implementing by a command interpreter or shell in order to start a new process? Answer: In the UNIX systems a fork system call followed by an ex

Explain the different sections of a process., Explain the different section...

Explain the different sections of a process.     Entry section     Critical section     Exit section     Remainder section Consider a system inclusive of n processe

What is time-stamping, time-stamping It is a method proposed by Lampor...

time-stamping It is a method proposed by Lamport, used to sequencing events in a distributed machine without the use of clocks. This process is intended to order events consis

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