Operating System-Unix (3i Infotech Papers): Sample Questions 1 - 3 of 78

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Question number: 1

» Operating System » Unix

Essay Question▾

Describe in Detail

Brief about the directory representation in UNIX.

Explanation

  • A UNIX directory is a file containing a correspondence between filenames and inodes.

  • A directory is a special file, it is maintained by the kernel- Only kernel modifies directory, but processes can read directories.

  • The contents of a directory are a list of filename and inode number pairs.

  • Kernel makes two entries when new directories are created

’. ‘

  • The directory itself.

’. . ’

  • Parent directory.

Kernel makes two entries

Kernel Makes Two Entries

Kernel makes two entries

Question number: 2

» Operating System » Unix

Short Answer Question▾

Write in Short

In what way the validity fault handler concludes?

Explanation

  • It sets the valid bit of the page by clearing the modify bit.

  • Maps the page to the memory

  • It recalculates the process priority.

Question number: 3

» Operating System » Unix

Essay Question▾

Describe in Detail

How are device represented in UNIX?

Explanation

  • Devices in UNIX are represented by files.

  • Each piece of hardware is a file.

  • Allows access to the hardware.

  • Device file is specified as ‘block special file’ with characteristics similar to a disk file.

  • Represents a device with characteristics similar to a keyboard.

Two types of devices are character devices and block devices.

ls-l/dev/zero

  • crw-rw-rw-1 root——/dev character device

ls-l/dev/sdal

  • brw-rw—-1 root –/dev/sdal block device

Two types of devices

Two Types of Devices

Two types of devices