Theory -90 :- FD drive

FD drive

Introduction :                           

 A floppy disk, also called a 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. Floppy disks are read and written by a floppy disk drive (FDD). Floppy disks, initially as 8‐inch (200 mm) media and later in 5¼‐inch (133 mm) and 3½‐inch (90 mm) sizes, were a ubiquitous form of data storage and exchange from the mid‐1970s well into the 2000s.   By 2010, computer motherboards were rarely manufactured with floppy drive support; 3½‐inch floppy disks can be used with an external USB floppy disk drive, but USB drives for 5¼‐inch, 8‐inch and non‐standard diskettes are rare or non‐existent, and those formats must usually be handled by old equipment. While floppy disk drives still have some limited uses, especially with legacy industrial computer equipment, they have been superseded by data storage methods with much greater capacity, such as USB flash drives, portable external hard disk drives, optical discs, memory cards and computer networks.

Floppy types: 8‐inch floppy disk

8‐inch floppy disk The first floppy disk was 8 inches in diameter, was protected by a flexible plastic jacket and was a read‐only device used by IBM as a way of loading microcode.[16]Read/Write floppy disks and their drives became available in 1972 but it was IBM's 1973 introduction of the 3740 data entry system[17] that began the establishment of floppy disks, called by IBM the "Diskette 1," as an industry standard for information interchange. Early microcomputers used for engineering,

 

5¼‐inch floppy disk

5¼‐inch floppy disk he head gap of an 80‐track high‐density (1.2 MB in the MFM format) 5¼‐inch drive (a.k.a. Mini diskette, Mini disk,) is smaller than that of a 40‐track double‐density (360 KB) drive but can format, read and write 40‐track disks well provided the controller supports double stepping or has a switch to do such a process. A blank 40‐track disk formatted and written on an 80‐track drive can be taken to its native drive without problems, and a disk formatted on a 40‐track drive can be used on an 80‐track drive. Disks written on a 40‐track drive and then updated on an 80 track drive become unreadable on any 40‐track drives due to track width incompatibility.

3½‐inch floppy disk                                             

 In the early 1980s, a number of manufacturers introduced smaller floppy drives and media in various formats. A consortium of 21 companies eventually settled on a 3½‐inch floppy disk (actually 90 mm wide) a.k.a. Micro diskette, Micro disk, orMicro floppy, similar to a design, but improved to support both single‐sided and double‐sided media, with formatted capacities generally of 360 KB and 720 KB respectively. Single‐sided drives shipped in 1983 and double sided in 1984. What became the most common format, the double‐sided, high‐density (HD) 1.44 MB disk drive, shipped in 1986.

Internal parts of a 3½-inch floppy disk:

• A hole that indicates a high-capacity disk.
•  The hub that engages with the drive motor.
•  A shutter that protects the surface when removed from the drive.
•  The plastic housing.
•  A polyester sheet reducing friction against the disk media as it rotates within the housing.
•  The magnetic coated plastic disk.
•  A schematic representation of one sector of data on the disk; the tracks and sectors are not visible on actual disks.
•  The write protection tab (unlabeled) is upper left.