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 logical address space and physical address space, What is logical a...

What is logical address space and physical address space? The set of all logical addresses formed by a program is known as a logical address space; the set of all physical addr

Define fifo page replacement algorithm, Define FIFO Page Replacement Algori...

Define FIFO Page Replacement Algorithm This policy simply eliminates pages in the order they arrived in the main memory. By using this policy we simply remove a page based upo

Explain components of conflict phase of dispatch latency, Explain Component...

Explain Components of conflict phase of dispatch latency The conflict phase of dispatch latency has two components 1. Preemption of any process running in the kernel. 2.

Major advantages of microkernel approach to system design, Q. What are the ...

Q. What are the major advantages of the microkernel approach to system design? Answer: Benefits usually include the following (a) Adding a new service doesn't require modify

Key piece of information stored in single page table entry, Define which is...

Define which is not a key piece of information, stored in single page table entry, supposing pure paging and virtual memory  A reference for the disk block which stores the pa

Rule a magnetic hard disk, Q. If magnetic hard disks eventually have the s...

Q. If magnetic hard disks eventually have the same cost per gigabyte as do tapes will tapes turn into obsolete or will they still be needed? Describe your answer. Answer: Tap

Explain hierarchical paging, Hierarchical paging Single way is to use a...

Hierarchical paging Single way is to use a two-level paging algorithm, in which the page table itself is also paged. A logical address is separated into a page number and a pag

Digital circuits and design , 1. Draw a schematic diagram of a CMOS inverte...

1. Draw a schematic diagram of a CMOS inverter and explain its operation. 2. Draw schematic diagrams of CMOS NAND and NOR gates, and explain their operation. 3. Explain what

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