3i Infotech Papers: Sample Questions 724 - 725 of 1245

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Question number: 724

» Operating System » Unix

Essay Question▾

Describe in Detail

How do you create special files like named pipes and device files?


  • Special files are created by the system call ‘mknod’.

  • Special file is created using following steps:

    • New inode is assigned by kernel.

    • Sets the file type as a pipe, directory or special file.

    • If the file type is a device file, major and minor device numbers are the two entries created.

  • Using the mknod command, special files are created:

    • mknod [options] name type [major minor].

  • Example:

    • For a disk, disk controller is the major device number and the disk is the minor device.

  • Unix example:

    • $ mknod < pipe name > p

Question number: 725

» Basic CS » Data Structures



Which is the simplest file structure?


Choice (4) Response








None of the above




Define sequential files

Define Sequential Files

Define sequential files

  • Sequential is the simplest file structure.

  • Contains records or other elements stored in order based some identifying data like account number.

  • Method also called pile file method.

  • When a new record is inserted, it is placed at the end of the file.

  • In the case of any modification or deletion of record, the record will be searched in the memory blocks.

  • It found it is marked for deleting and new block of record is entered.

  • In order to locate the desired data, sequential files are read starting at the beginning.

  • Ideal for storage on a sequential access device magnetic tape or on a direct access device such as magnetic disk.

  • Contrast with random file.

Advantages of Sequential File Organization:

  • The design is very simple compared to other file organization.

  • Min effort involved in storing data.

  • Good method for report generation or statistical calculations.

  • Data stored in cheap magnetic tapes.

Disadvantages of Sequential File Organization:

  • Sorted file method always involves the effort for sorting the record.

  • Each time any insert, update, or delete transaction is performed, file is sorted.

  • Identifying the record, inserting, updating, deleting the record, always takes some time and may make system slow.