Floppy

STORAGE

DEVICE

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INTRODUCTION The storage device is an essential component in digital computer.It is needed for storing the programs & data. There are 2 types of storage device. 1. Primary 2. Secondary Secondary memory device such 2 as magnetic & tapes contain

DISK DRIVES

Disk drives are usually refer to secondary storage device (ROM). Information stored in most type of drives can be accessed & update quickly & easily. Disk drives read from & write to the media in a serial format. There are several types of disk drives given bellow 1. FLOPPY DISSK DRIVES. 2. HARD DISK DRIVES 3

FLOPPY DRIVES A floppy dives is an essential type of storage device.a disk drive with removable disk is called as floppy drive. The disk used with a floppy drive are small removable disk made by plastic , coated with magnetic recording material . A floppy drive has a media ,a floppy disk that is easily removable & small in physical size and /or capacity. 4

IDENTIFICATION OF FLOPPY DISK • IF WE HAVE TO IDENTIFY BETWEEN HARD DISK & FLOPPY DISK THEN FOLLOWING POINT ARE PRESENT 1. IN THE CASE OF FLOPPY DISK HEAD ALWAYS TOUCHS THE DISK. 2. IN THE CASE OF HARD DISK IS ALWAYS SPINNING.

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Construction of floppy drive The floppy disk is made by nonmagnetic material, while it is coated by magnetic material which is used to store the data. there are read & write head used to read & write on the disk respectively. There are stepping motor is used to move the head according to controller pin. Disk hub is used to clamp the disk for spinning of disk to access the desire portion of disk Whole structure is covered by shell , while disk is protected by liner. Insertion key, write p. key is also situated. 6

TRACKS AND SECTORS

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TYPE OF FLOPPY DISK Floppy disk are classified on basis of their size,these size are following . 1.) 8 “ 2.) 5.25 ” 3.) 3.5 “ Usually with decrease in size, storage capacity increases. Among these 3.5 ‘” floppy commonly used today ,due to 1.Small in size to fit in a shirt pocket. 8 2.They have built in size “window” to protect

HISTORY OF FLOPPY The first floppy drive was come with IBM pc was 5.25” & stored 360 k byte of data. which was DSSD. but now it is 1.2 M byte DSDD IN 1980 IBM introduced a new floppy disk which was 3.5” & storage capacity was 1.44 M byte & DSHD. There is another floppy which has

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3.5 INCH FLOPPY DRIVE SHELLSPECIFICATION It has a tough, high impact plastic shell.It is just 3.7 inch from front to back & 3.5 inch wide.It’s weight is 22 grams. LINERS To protect the floppy disk,a thin sheet of unwoven cloth akin is provided on each side of the medium from the shell. HUB Every time you slide a disk into the 10 drive ,drive hub clamp onto the disk

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INSERTION KEY There are 8 possible way to enter your disk into disk drive & only one is correct.so insertion key provide the right direction to insert your floppy.

DENSITY KEY This key is actually the present or absent of a hole in one corner of the disk.double density key lack a hole while high density have a hole.

WRITE PROTECTION It is right against to write new data in floppy.in 5.25 inch floppy ,if notch is covered by a tab.the information in the disk is protected & 12 vice versa.

100 MB TECHNOLOGY The storage capacity of floppy is 1.4Mb , which is not sufficient usually that’s why new technology introduces in the form of zip disk Storage capacity of zip disc is about 95.8 Mb. we can’t format the zip disc for increasing the storage capacity of 13 it because its servo can’t be

WORKING OF CONTROLLER Controller When we press the save button ,the keystroke is detects pc hardware & recognize by its BIOS. 3 Then BIOS send the electronic code to our program & our program send request to DOS to write on the disk 4 DOS send instruction to BIOS & BIOS send to part of disk control hardware. 5 This hardware tells drive to move its head . 14 6 Finally the head read the content

WORKING OF FLOPPY DISK 1.

Two signal control the head position ,one signal move the head according to step pulse by stepper motor & another signal control the direction of the head.

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To determine which of the side of double disk is read “write signal” signal is used ,it tells the disk drive to use upper head .(by default lower head).

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Writing on the require two signal. ”write data” comprises the information that is actually to be written on the disk.

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Stepping motor is used to move the read/write head for getting the data from desire drive surface

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Finally the controller commands the head to read or write the information.

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The information is encoded using following methods

FM ENCODING RULE MFM ENCODING RULE RUN LENGTH ENCODNG RULE 15

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PARAMETERS OF FLOPPY DRIVE

1. Calculation of the capacity of drive There is the formula to calculate the disk capacity (No of bytes /sector)* (no of sector /track)* (no of track /surface)*(no of surface). 2. Drive access time Track seek time+ Rotational delay+ Transfer time. 17

MECHANICAL DESIGN

To carry out their design purpose ,we have to study it’s mechanical design. Speed control A servo system keeps the disk spinning at the correct speed. HEAD SPEED CONTROL The stepper motor moves the head with respect to appropriate voltage pulses. HEAD INDEXING The head can put on a right place with assurance ,the resorts to a process called 18 “INDEXING”.

USES & APPLICATION The application of floppy drive are as follows 2. These are used as the main type of secondary storage device. 3. We can transfer the information from one computer to another computer. 4. To provide the backup or save the copy of information contain in the hard disk. 5. Unlike the audio & video disk ,when we get copy of copy of program 19 quality is not degrade.