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 are the different constituents of a process, Problem: a) Define th...

Problem: a) Define the term ‘process' and what are the different constituents of a process. b) In the three-state process model, what does each of the three states signify?

What are the drawbacks of spiral model, What are the drawbacks of spiral mo...

What are the drawbacks of spiral model? I. It is based on customer communication. If the communication is not proper then the software product that gets developed will not be t

What are privileged instructions, What are privileged instructions? Som...

What are privileged instructions? Some of the machine instructions that may cause harm to a system are designated as privileged instructions. The hardware permits the privilege

Describe the state when you run an unlink operation, Describe when you run ...

Describe when you run an unlink() operation to remove a file on the ext3 file system. Be specific about what disk blocks have to be written where in what order. State your assumpti

Quantum settings denoted by q, Determining the time quantum for a job is a ...

Determining the time quantum for a job is a critical task. Given the assumptions that the average switching time between processes is s, and the average amount of time an I/O bo

When page fault frequency in an operating system is reduced, When the Page ...

When the Page fault frequency in an operating system is reduced Locality of reference is appropriate to the process

Demand-paging system, Consider a demand-paging system with the following ti...

Consider a demand-paging system with the following time-measured utilizations: CPU utilization: 10%, Paging disk: 98%, Other I/O devices: 5%. What does this imply? How to improv

Define the client - server communications environment, Define the Client - ...

Define the Client - Server Communications Environment Today's client - server communications environment offers programmers great flexibility for application design. Applicatio

What do you mean by first fit, What do you mean by first fit? First fit...

What do you mean by first fit? First fit allocates the first hole that is big sufficient .Searching can either start at the starting of the set of holes or where the previous f

Unsafe state, discuss unsafe state in operating system

discuss unsafe state in operating system

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