3i Infotech Papers: Sample Questions 80 - 82 of 1245

Examrace Placement Series prepares you for the toughest placement exams to top companies.

Question number: 80

» Operating System » Unix

Essay Question▾

Describe in Detail

Brief about the directory representation in UNIX.


  • 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: 81

» Basic CS » Data Structures

Short Answer Question▾

Write in Short

If a binary tree has 20 nodes then it has how many null branches?


  • A binary tree with 20 nodes has 21 many null branches.

  • Consider, a tree with 5 nodes (n = 5)

  • No. of null pointer = 2n- (n-1) =n + 1

  • When, n = 20

  • Then n + 1= 20 + 1=21

Question number: 82

» Database » MySQL

Essay Question▾

Describe in Detail

What is System R? What are its two major subsystems?


Figure of the system R

Figure of the System R

Figure of the system R

  • System R was designed and developed over a period of 1974 - 79 at IBM San Jose Research Center.

  • It is a prototype and its purpose was to demonstrate that it is possible to build a Relational System that can be used in a real life environment to solve real life problems, with performance at least comparable to that of existing system.

    Its two subsystems are

    • Research Storage

    • System Relational Data System.