Floppy disk & drive

1. Floppy Disk & Drive Its Construction & working - M.K.Devaki

2. Synopsis : Floppy Disk What is a floppy disk ? Usage of Floppy disk Types of Floppy disk Components / construction Floppy Drive Construction Working Connectors

3. 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).

4. 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. 

5. 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.

6. 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 or 2.88 Mb Hard plastic case

7. 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.

8. Floppy Disk :

9. 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.

10. 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.

11. Working of Floppy disk drive : Exposing the Recording Surface Sending Signals From the Circuit Board Checking for Write Protection Positioning the Read/Write Heads Writing the Data

12. Disk presence switch is the mechanism called diskette changeline signal to form controller board that disk has been removed.

13. Floppy connectors :