Two marks Questions with Answers

Two Marks Questions with Answers

Q.1 What are the essential requirements for long term information

Ans. Name, type, location, size, protection and time, date for file.

Q.2 State the typical bad sector transactions.

Ans. :

a. O.S. tries to read logical block 87.

b. The controller calculates the ECC and finds that the sector is bad. It reports this finding to the O.S.

c. Next time the system is rebooted, a special command is run to tell the SCSI controller to replace the bad sector with a spare.

d. After that, whenever the system requests logical block 87, the request is translated into the replacement sectors address by the controller.

Q.3 What are link and unlink directory operations?

Ans. Link Links a file to a new name in the file system directory structure, creating a new directory entry for an existing node.

Unlink : It removes a directory entry for a file.

Q.4 What data type is file ?

Ans. A file is an abstract data type.

Q.5 Give an example of an application that could benefit from operating system support for random access to indexed files.

Ans: An application that maintains a database of entries could benefit from such support. For instance, if a program is maintaining a student database, then accesses to the database cannot be modeled by any predetermined access pattern. The accesses to records are random and locating the records would be more efficient if the operating system were to provide some form of tree based index.

Q.6 What is the content of a typical file control block ?

Ans. FCB contains in formation about the file, including ownership, permissions and location of the file contents.

Q.7 What are the functions of file organization module in file system?

Ans. File organization module can translate logical block addresses to physical block addresses for the basic file system to transfer.

Q.8 Discuss about file descriptor and access control matrix.

Ans. Protection mechanisms provide controlled access by limiting the types of file access that can be made. Protection can be viewed abstractly as a matrix, called an access control matrix. A file descriptor is an index into a small table of open files for the process. Descriptors start at 0 and seldom get higher than 6 or 7 for

programs, depending on the maximum number of simultaneously open files typical

Q.9 What is a file? List some operations on it.

Ans. File is an unstructured sequence of data, File operations are read, write, create, delete etc.

Q.10 What are the various file accessing methods?

 Ans. Sequential access, direct, indexed etc.

Q.11 Write the attributes of a file.

Ans. Name, identifier, type, location, size, time and date.

Q.12 Mention any four file attributes.

Ans. Name, type, size and location.

Q.13 Differentiate absolute path from relative path.

Ans. An absolute path name begins at the root and follows a path down to the specified file, giving the directory names on the path. A relative path name defines a path from the current directory.

Q.14 What are the two types of system directories ?

Ans.A tree structured directory that allows a user to create subdirectories to organize the files.

A general graph structure that allows complete flexibility in the sharing of files and directories.

Q.15 What is garbage collection?

Ans. Garbage collection is the process of automatically freeing objects that are no longer referenced by the program.

Q.16 Mention the major attributes and operations of a file.

Ans. Major attributes of file is name, identification, type, location, size and protection. Operation on a file is to create, write, read, reposition, delete and truncate files.

Q.17 What is meant by free-space management ?

Ans. To keep track of free disk space, the system maintains a free space list. Free space list. Free space list records all free disks blocks i.e. those not allocated to some file or directory.

Q.18 Name any four common file types.

Ans.File types are text file, source file, object file and executable file.

Q.19 What is NFS ?

Ans. The Network File System (NFS) is probably the most prominent network service using RPC. It allows you to access files on remote hosts in exactly the same way you would access local files. A mixture of kernel support and user-space daemons on the client side, along with an NFS server on the server side, makes this possible. This file access is completely transparent t to the client and works across

Q.20 What is virtual file system? W

Ans. Virtual File Systems (VFS) provide an object-oriented way of implementing file systems. VFS allows the same system call interface to be used for different types of the systems.

Q.21 Write short note on file system mounting.

Ans. Mounting a file system, means taking that storage and connecting it to the operating system in a way that it's usable as a hierarchical storage device with directories and files. This could be the initial file system or another file system that connects to the root file system at a mount point.

Q.22 What is file management system ?

Ans. File management system consists of system utility programs that run as privileged applications. The way a user or application may access files and programmer does not need to develop file management software.

Q.23 What are the disadvantages of log structured file systems?

Ans. It requires cleaning demon to produce clean space, which takes additional CPU time. Reads that are not handled by buffer cache are same performance as normal file system.

Q.24 List the objectives for a file management system.

Ans.Objectives are :

1. Meet the data management needs and requirements of the users

2. Guarantee that the data in the file are valid

3. Optimize performance

4. Provide I/O support for a variety of storage device types

5. Provide I/O support for multiple users.

Q.25 What is a file management system ?

Ans. It is a set of system software that provide services to user and applications in the use of files.

Q.26 What are the disadvantages of log-structured file systems ?

Ans. It decreases head contention and seek times.

Q.27 Define log structured file.

Ans. Log structured file is used for file system meta data updates.

Q.28 List out the major attributes and operations of a file.

Ans.

Attributes of file: Name, identifier, type, location and size.

Operation on file : read, write, create, delete.

Q.29 Do FAT file system is advantageous? Why? 

Ans. The FAT file system protects files by storing two copies of the file allocation table on the FAT volume. FAT contains the FAT structure, which is a map of the data region. File size is no longer fixed. We do not need to know the size of the file at the beginning.

Q.30 Identify the two important functions of Virtual File System (VFS) layer in the concept of file system implementation.

Ans. : Two important functions :

1. It separates file system generic operations from their implementation by defining a clean VFS interface.

2. VFS provides a mechanism for uniquely representing a file throughout a network.

Q.31 Differentiate between file and directory.

Ans. The basic difference between the two is that files store data, while directory store files and other directory. File is a sequence of logical records. Directory lists the file by name and includes the file location on the disk, length, type etc.

Q.32 Write about swapping. Let us assume the user process is of size 1 MB and the backing store is a standard hard disk with a transfer rate of 6 MBPS. Calculate the transfer rate.

Ans. :

Q.33 What is the advantages of bit vector approach in free space management

Ans.: Advantages: It is simple and its efficiency in finding the first free block on the disk is high.