8th Class Computers Science Characteristics of Memory Devices Introduction to Secondary Memory

   Introduction to Secondary Memory  

  Floppy Disk Drive (FDD)

The floppy disk is a storage media that is used to store data permanently. It is made up of a flexible plastic called myler or vinyl plastic, which is coated with magnetic oxide. The floppy disk is also available typically 3.5, 5.25 or 8 inches in diameter with two versions. Floppy disk is a portable storage media but its reliability is very less. Normally floppy disk is available in single density or double density they can store data on one or both the surfaces of a diskette.  

 Hard Disk

The hard disk is another type of permanent storage media that is used to store huge volume of data. It is a reliable storage media. The storage capacity of hard disk is more than 160GB. A hard disk is physically composed of a series of flat, magnetically coated platters stacked on a spindle. A hard disk drive consists of many inflexible magnetic disks mounted on a motor. These disks are turned by high speeds motors. The stored data of hard disk is read and write by read/write heads. There are four types of hard disk available in market.  

 These are the following: 

• ATA (Advanced Technology Attachment)
• Serial ATA
• RAID (Redundant Array of Inexpensive Disk)  

 ATA (Advanced Technology Attachment)

Its data transfer speed between hard disk and system is up to 100 MB per second.  

 Serial ATA

Its data transfer speed between hard disk and system is up to 600 MB per second.      

 Raid (Redundant Array of Inexpensive Disk)

This technology combines more than one hard disk in an array. It is reliable data storage. If one hard disk fails the data can be retrieved easily.  

 Pen Drive

Pen drive is a reliable and portable storage medium. It is also called USB drive. It does not require any expansion card or device driver to connect any peripheral to the computer.  

 The floppy disk is a storage media that is used to store data permanently. Floppy disk is available in............inches diameter.

(A) 3.5                                                                  

(B) 5.25

(C) 8                                                                      

(D) All of these

(E) None of these  

Answer: (d)

Explanation

Correct Option:

(D) The floppy disk is also available typically 3.5, 5.25 or 8 inches in diameter

Incorrect Option:

Rests of the options are invalid.  

  The hard disk is a type of permanent storage media used to store huge volume of data. It is a reliable storage media. The transfer speed of SATA hard disk is ................... MB per second.

(A) 100                                                                 

(B) 300

(C) 600                                                                 

(D) 1000

(E) None of these

Answer: (c)

Explanation

Correct Option:

(D) The data transfer speed of SATA is up to 600 MB per second.

Incorrect Option:

Rests of the options are invalid.    

 RAID is reliable data storage. RAID technology combines more than one hard disk in an array. The full form of RAID is.......

(A) Redundant Array of Inexpensive Disk

(B) Redundant Array of Index Disk

(C) Redundant Array of Interactive Disk

(D) Redundant Array of Imperative Disk

(E) None of these

Answer: (a)

Explanation

Correct Option:

(A) RAID (Redundant Array of Inexpensive Disk) technology combines more than one hard disk in an array.

Incorrect Option:

Rests of the options are invalid.  

• Pen drive does not require any expansion card or device driver to connect any peripheral to the computer.
• In 1980, Seagate Technology introduced the first hard disk drive.  

• DRAM: Is one of the forms of semiconductor RAM
• SRAM: Is based on the logic circuit known as a flip-flop.
• EPROM:  Is a special type of PROM that provides update permission on a PROM memory chip.
• ATA: Its data transfer speed between hard disk and system is up to 100 MB per second.
• Serial ATA: Its data transfer speed between hard disk and system is up to 600 MB per second.  

• RAM is a temporary memory that provides permission to Read and Write over the memory chip.
• A static RAM chip can store only about one-fourth as much data as a DRAM chip of the same complexity.
• ROM is a type of memory that stores the instructions, which are necessary for starting up the computer.
• A hard disk drive consists of numbers of inflexible magnetic disks mounted on a motor.
• Pen drive is a reliable and portable storage medium. It is also called USB drive.
• RAID technology combines more than one hard disk in an array.
• In manufacturing the electronic circuit (chips), silicon is the primary building blocks used in it.
• RAM is volatile by nature, which means that it needs continuous flow of electricity to keep its content safe
• The floppy disk is also available typically 3.5, 5.25 or 8 inches in diameter with two versions.
• A hard disk drive consists of numbers of inflexible magnetic disks mounted on a motor.    

 Abbreviations

ATA        ----         Advanced Technology Attachment

RAID      ----         Redundant Array of inexpensive Disk

PROM   ----         Programmable Read-Only Memory