Alan Shugart created floppy disk drive
Extrenal storage device
Stores data on magnetic surface
Used for transferring data from one computer to another
8’’ floppy could store data on one side and FDD could only read data from the floppy. Capacity was about 100 KB. It was then upgraded to incorporate read and write on the floppy disk and the capacity increased to 250 KB
5.25 inch floppy was similar to 8 inch disk and could store 160 KB of data. It was modified to store data on both sides and capacity increased to 360 KB. Then double sided high density floppy disk holds 1.2 MB of data
5.25 floppy disk has a write protect notch and has an index hole to identify the starting sector by FDD
3.5 inch had a high density and could hold 720 KB of data and then density increased to hold 1.44 MB of data. It has two holes at the bottom of the disk. One enables to identify if floppy disk has a low density or high density and other is a write protect tab
Protects data from being accidentally modified or erased
Sliding the switch down makes the floppy disk read only
Sliding the switch up enables data to be read and written to the floppy disk
Reads and writes data to the floppy disk
Shares the name with the size of the floppy disk that it uses
5.25 inch FDD
3.5 Inch FDD
Floppy drive spins the floppy disk at a speed of 300 rotations per minute
Read write head – Position of read write head on both sides of the drive is such that they are not opposed to each other. Uses same head to perform both reading and writing data on floppy disk. Consists of two parts: first part reads and writes data on floppy disk and second part erases data from a track before read write head writes
Circuit Board – send data signals to different parts of FDD. Controls speed of motors and manages position of read write head over required track
FDD Controller – affixed on motherboard
Faceplate – it is recommended to mount FDD from outside to cabinet
Connectors – uses a small sized connector called mini plug
Cables – uses 34 pin data cable
Reading Data from the Floppy Disk :
User executes command
Spindle motor rotates the floppy disk
Stepper motor moves the read write head over the required track
Read write head reads the data
Floppy disk drive sends the data to the microprocessor for processing
Spindle motor stops rotating the floppy disk
Writing Data to the Floppy Disk :
User executes command
Spindle motor rotates the floppy disk
Stepper motor moves read write head over the required track
Erase coils on the read write head erases data from the track
Write head is energized
Write head converts binary data into electromagnetic impulses
Write head writes the data on the floppy disk
Spindle motor stops rotating the floppy disk
Wipes out all the data stored on the floppy disk
Creates sectors and tracks on the floppy disk like creating shelves in new cupboard
Manufacturer usually formats the floppy disks before supplying them
Head of FDD sometimes gets misaligned because at times we remove floppy from drive before it has stopped its operation
Floppy disks written in a drive with its head misaligned is readable only in the drive and displays an error if it is read by another drive
Drive Probe software enables you to align the read write head
Floppy disk drive may have some problems which can corrupt the floppy disk
Problems that may occur if the floppy disk drive is damaged are :
