What is Floppy Disk and Types of Floppy Disks

Also known as a Diskette. The most common magnetic data storage medium used on computer is a floppy disk. These are made of an ultra thin, circular, Mylar plastic and coated with magnetic material. Floppy disks are commonly used as secondary storage and backup memory in a personal computer. These disks are very thin and flexible. It is cheaper than any other storage devices and portable. Data can be written (or) erased on a floppy disk.  In 1971, IBM introduced the 8 inch floppy disk, 1976, 5.25 (5¼) inch floppy disk were introduced by Shugart Associates and another most popular 3.5 (3½) inch floppy disk introduced Sony in 1980. The 3.5 (3½) inch floppy used in the ’A’ drive and the older 5.25 (5¼) inch floppy used in the ’B’ drive. The capacity of a 5.25 (5¼) inch floppy typically holds 1.2 mega bytes of information and each 3.5 (3½) inch floppy holds 1.44 megabytes of information. The advantage of floppy disks is that they can be removed from the computer and the data taken to another computer system.

There are three types of Floppy Disks available they are :

3.5" Floppy Disk Capacity 1.44 Mb (Megabytes) Introduced : Sony (1980)

5.25" Floppy Disk Capacity 1.2 Mb (Megabytes) Introduced : Shugart (1976)

8.0" Floppy Disk Capacity 100 Kb (Kilobytes) Introduced : IBM (1971)

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What is Hard Disk and Types of HDD

The Hard drive also called the hard disk or fixed disk. This is the main storage for a computer and Non-volatile storage device. Every computer has a hard disk they are used to store the data files. Computers store information in two locations, First one, the computer’s RAM is used as a temporary storage location since whatever it contains is lost when the computer is powered off and Second one, Information that is stored permanently is written to the hard drive. Hard disk/Hard drive is different from RAM, because the information stays stored even if the power is turned off. Hard Drive can store a large amount of computer data in a small space and it storage provides faster access to files than a diskette.

Hard disks contain a number of magnetic platters that store information in the form of 0’s & 1’s and is stored in a series of concentric circles. A hard disk consists of one (or) more platters and several read/write heads that read and record data magnetically on platters, a stack of rotating disks inside the hard drive.  A read/write head is the device that reads the data from the disk platter into the computer.


Types of HDD (Hard Disk Drives) :
1.    IDE : Integrated Drive Electronics. it also known as PATA drives ( Parallel Advance Technology Attachment )
2.    SATA : Serial ATA or Serial Advance Technology Attachment.
3.    SCSI : Small Computer System Interface.
4.    SAS : Serial Attached SCSI.


Types of Hard Disk interfaces:

HD drives come in two main sizes, (i) 2.5" for laptops and (ii) 3.5" for desktops.

•    Desktop Hard Disk Types :- 3.5', IDE and SATA Interfaces.
•    Laptop Hard Disk Types :- 2.5', 1.8', IDE, SATA, SCSI.
•    Server Hard Disk Types :- 3.5', SATA, SCSI.

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