File Management Questions and Answers pdf

 Define a File system?

Files are managed by the operating system. The part of the operating system that deals with files are known as the file system. The major responsibilities of the file system are:

• How files are structured?
• How files are accessed and used?
• How files are protected? etc.

What are File attributes?

All operating systems associate the following information with each file, such as:

• Date and Time when the file was created or modified.
• Size of the file in bytes or KB or MB or higher memory units.
• Location of the file with the complete path on the storage media.
• Type of file.
• The Identifier, which identifies the file within a file system.

The file name and the above-mentioned information about a file is known as attributes of the file. The attributes vary from one operating system to another.

Describe the Direct Access Method?

The direct access method is also known as the random access method. It is a very fast method to access data from files. With direct access, the information from any location within the file may be accessed directly and quickly. The data file contains fixed-length logical records. The data file is viewed as a numbered sequence of blocks or records. The block number is normally relative. A relative block number is an index relative to the beginning of any file in a system. Thus, the first relative block of any type of file is 0, the next is 1, and so on.

Therefore, the direct access method is also referred to as the relative access method. A direct access file allows arbitrary locks to be read or written.

 For example:

 After block 16 has been read, block 144 could be the next and then block 24. There is no restriction on the order of reading or writing for a direct access file in the computer management system.

Describe Indexed Access Method?

The indexed access method is the modified form of the sequential access method. This method generally involves the creation of an index for the file. The index is like an index at the end of a book, which is used to go to a specific topic very quickly. With indexed access, each record of a file has one or more fields. One field is USD as an index field or key field. The record is organized in a logical sequence according to a key field contained in each record. Records are accessed only through the indexes.

What is meant by Access Control in the file system?

Important data can be protected from unauthorized access by restricting access dependent on the identity of the user. Different types of users may need different types of access to a file or directory in a system. This control is achieved by access control, which limits who can access files and how they can access them. In this scheme, each file/directory is associated with the Access Control List (ACL), which specifies the user names and the types of access allowed for each user. When a user requests the operating system to access a particular file, the operating system checks the ACL associated with that file. If the list contains the user name and that user is granted access right to access the file, then the access is allowed. Otherwise, a protection violation occurs, and access is not allowed to that user.

What is file locking?

File locking mechanism provides functionality similar to reader-writer locks. A reader-writer lock requires specifying the mode of the lock either read or write access in a system. When a process wishes to only read shared data, it requests the reader-writer lock in reading mode Similarly, when a process wishes to modify the shared data, it must request the lock in write mode.

What is file allocation? Name file allocation methods.

A file is stored on the secondary storage as a collection of memory blocks. The file management system (a part of the operating system) is responsible for allocating blocks to files. This is called file allocation.

The most popular and commonly used allocation methods are:

• Contiguous allocation 
• Linked allocation
• Indexed allocation

What is Free Space Management?

The disk space (or secondary storage) is limited, Therefore we must manage the free space of the disk properly. The operating system must be able to identify those physical blocks that are not currently allocated to any file. Most of the operating system maintains a free space list, which contains the records of all free disk blocks. When a new file is created, the operating system searches the free space list. If free space is available, it is allocated to the new file and the free space list is updated. Similarly, if a file is deleted, then a space allocated to that file is added to the free space list.

Introduce the Bitmap method?

The most popular method to implement (or maintain) the free space list is the bitmap method. It is also referred to as bit vector. Using this scheme, the status of each block is represented by a single bit. If a block is free, the bit is set to 0. Similarly, if a block is allocated, the bit is set to 1.

Name most commonly used Directory Structure?

The directory structure varies from system to system. The most important and commonly used directory structure is:

• Single-Level directory 
• Two-Level Directory
• Tree-Structured Directory
• Cycle Graph or General Graph

What is an Acrylic Graphy?

Acrylic graph means a graph with no cycle. This is a directory structure that is used by some operating systems to allow directories to share subdirectories and files. The same file or subdirectory may be in two different directories in an acrylic graphy. A shared file or subdirectories is not the same as two different copies of a file/subdirectory, but only one actual file/subdirectory exists. A new file created by one user will automatically appear in all the shared subdirectories. 

What do you about particular?

Files are stored in secondary storage such as a hard disk. The hard disk can be divided into different logical parts. These logical parts of the disk are known as particular. A file system can be created on each of these partitions of the disk.