Question

4. What are the ways to access the same files in more than one place in the directory structure? Explain and justify your answer. (10 points)

Answer 1

A directory may be a container that's wont to contain folders and file. It organizes files and folders into a hierarchical manner.

Directory D1 D11 D12 D13 D14 F1 F2 F3 F4 F5 F6 F7 F8 F9 Files

There are some logical structures of a directory, these are given below.

Single-level directory –

Single level directory is simplest directory structure.In it all files are contained in same directory which make it easy to understand and support.
A single level directory features a significant limitation, however, when the amount of files increases or when the system has quite one user. Since all the files are within the same directory, they need to have the unique name . if two users call their dataset test, then the unique name rule violated.

Directory D1 D2 D3 D4 D5 D6 D7 D8 f1 f2 f3 f4 f5 f6 f7 f8 Files

Two-level directory –

As we've seen, one level directory often results in confusion of files names among different users. the answer to the present problem is to make a separate directory for every user.
In the two-level directory structure, each user has there own user files directory (UFD). The UFDs has similar structures, but each lists only the files of one user. system’s main file directory (MFD) is searches whenever a replacement user id=s logged in. The MFD is indexed by username or account number, and every entry points to the UFD for that user.

user1 user2 user3 user4 Directory D1 D2 D3 D4 D5 D6 D7 D8 f1 f2 $2 f4 f5 f6 f7 f8 Files

Tree-structured directory –

Once we have seen a two-level directory as a tree of height 2, the natural generalization is to extend the directory structure to a tree of arbitrary height.
This generalization allows the user to create there own subdirectories and to organize on their files accordingly.

Root Directory ОО Files

Acyclic graph directory –

An acyclic graph may be a graph with no cycle and allows to share subdirectories and files. an equivalent file or subdirectories could also be in two different directories. it's a natural generalization of the tree-structured directory.
It is utilized in things like when two programmers are performing on a joint project and that they got to access files. The associated files are stored during a subdirectory, separating them from other projects and files of other programmers, since they're performing on a joint project in order that they want the subdirectories to be into their own directories. The common subdirectories should be shared. So here we use Acyclic directories.

Root Directory () Files

General graph directory structure –

In general graph directory structure, cycles are allowed within a directory structure where multiple directories are often derived from quite one parent directory.
The main problem with this type of directory structure is to calculate total size or space that has been taken by the files and directories.

Root U1 U2 U3 Directory D1 D2 D3 D4 D5 D6 D7 D8 Files D9 D10