FLOPPY DISK & DRIVE

ITS CONSTRUCTION & WORKING

What is a floppy disk ?

A floppy disk, or diskette, is

a disk storage medium

composed of a disk of thin

and flexible magnetic

storage medium, sealed in a

rectangular plastic carrier

lined with fabric that removes

dust particles. They are read

and written by a floppy disk

drive (FDD).

Usage of Floppy Disk :

Floppy disks are used for emergency boots in systems

lacking support for other bootable media, and

for BIOS can still be executed from bootable floppy

disks. If BIOS updates fail or become corrupt, floppy

drives can sometimes be used to perform a recovery.

The floppy disk was the primary external writable

storage device used.

Types of Floppy Disk :

According to the size, floppy disks are generally classified into two:

• 5 .25 -inch diskette

• 3 .5- inch diskette A normal 3½ inch disk can store

1.44 megabytes of data.

Zip Drive

Zip drives were introduced by the Iomega corporation in the mid 1990s. A zip disk was capable of storing 100 megabytes, 250 megabytes and even 750 megabytes on a single disk. Zip drives were mainly available as a peripheral that could be added to an existing system.

Types of Floppy disk cont.

Abbr. Floppy Disk Type Capacity Info

SS/SD or 1S/1D Single Sided, Single Density

100 K First generation. Capacity varies

SS/DD or 1S/2D 5-1/4 inch Single Sided, Double

Density

180 K

DD/DD or 2D/2D 5-1/4 inch Double Sided, Double

Density

360 K Most common type in the early 1980's

DD/HD or 2D/HD 5-1/4 inch Double Sided, High

Density

1.2 Mb

DD 3.5 inch Micro Floppy, Double

Density

720 K Hard plastic case

HD 3.5 inch Micro Floppy, High

Density

1.44 Mb or2.88 Mb

Hard plastic case

Floppy Disk Makers in 1980

Diskmakers included:

Tandy, Memorex,

Dysan, MicroUniversal,

BASF, Datam,

Verbatim(Datalife), 3M,

Fuji Film, Janus, Maxell,

Highland, NEC, Albinar,

Businessland, Kodak,

IBM, Sony, Precision,

Packard Bell, and others.

Floppy Disk :

Floppy disk Construction

A floppy is made up of a circular thin Mylar plastic material

coated with magnetic particles sealed into 90x94 mm plastic

case. Every magnetic particles holds one data bit.

The Shutter with spring is present to avoid dust particles from

being depostied.

Inserting inside the drive, the shutter opens allows magnetic

media expose to Read / Write head.

Hub is a hole through which floppy disk is rotated by spindle

or stepper motor.

Paper ring Clean the disk by removing microscopic bits of

dust.

Floppy drive construction :

Made of ferrite type to make them electromagnetic.

Head contacts much closer compared to HDD due to

low rpm [300 rpm]

3.5 Floppy disk has only 80 tracks per side so the

actuator doesn’t need to be much precise as HDD.

Unlike HDD, FDD has 3 heads :

One is Read/Write head

And other two is tunnel –erase head to clean up after r/w head

as there is a magnetization that overlaps two adjacent tracks

while writing.

Working of Floppy disk drive :

1) Exposing the

Recording Surface

2) Sending Signals

From the Circuit

Board

3) Checking for

Write Protection

4) Positioning the

Read/Write Heads

5) Writing the Data

Disk presence switch is the mechanism called

diskette changeline signal to form controller board

that disk has been removed.

Floppy connectors :

Thankyou