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

Briefly discuss on bankers algorithm, Briefly discuss on Bankers algorithm?...

Briefly discuss on Bankers algorithm? The resource-allocation graph algorithm is not applicable to a resource-allocation system with multiple examples  for each resource type.

Explain medium term scheduling, Medium term scheduling This is componen...

Medium term scheduling This is component of the swapping function. Usually the swapping in decision is based on the need to manage the degree of multiprogramming. At a system t

Explain many-to-one model (green threads), Many-to-One Model (Green Threads...

Many-to-One Model (Green Threads) Implementations of the many-to-one model a lot of user threads to one kernel thread permit the application to create any number of threads tha

Conservative garbage collection, Conservative GC can be used for languages ...

Conservative GC can be used for languages such as C and C++, which were not explicitly designed for garbage collection. This is a non-copying technique. A conservative garbage coll

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

Semaphore examples, Ok so i think i got this right by not 100% on this. wha...

Ok so i think i got this right by not 100% on this. what I want to figure out is if there are x visitors that can line up for a ride but only 1 passenger can get on the ride at a t

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

Major page fault, Major page fault: If the page is not loaded in memory a...

Major page fault: If the page is not loaded in memory at the time the fault is stated, then it is named major or hard page fault. The handler in the machine requires to search a

What is the lower bound on the numeral of page faults, Q. Presume that you...

Q. Presume that you have a page-reference string for a process with m frames (initially all empty). The page-reference string has length p along with n distinct page numbers

Thread pools, Another solution then would be to keep a pool of threads. Whe...

Another solution then would be to keep a pool of threads. Whenever a new task arrives, the system would simply get a thread from pool and set that thread to work on the given task.

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