Floppy Disk

Read about Removable storage here.

The floppy drive is a good example of how the standard itself is more important than the technology...

The capacity and data transfer rates of floppy drives saturated at extremely low levels (1.44 MB and about 0.06 MB/sec). These parameters could be improved dramatically with today's technology but... do not expect changes. There are millions and millions of floppy drives out there and it is too late to change standards.

Today, the only two functions left for the floppy disks are serving as boot disks in the case of system conflicts on your PC and serving as movable storage for those who still live in the sub-two-megabytes-of-storage world. The main advantage of floppy drives is still low cost and universal compatibility.

In its design, the floppy disk is similar to the hard drive: it operates on the principles of magnetic recording, it uses magnetic heads for data storage and retrieval from the rotating magnetic media. The main differences are in the quality of the media (with much lower magnetic performance for the floppy) and low rotational speed of the disk - about 300 rotations per minute. Another difference - continuous contact between two spring-loaded sliders and the media is not, most likely, going to exist forever. Today's hard drives already show some level of slider-disk interference at much higher velocities (beyond 7500 rpm).

The history of floppy drives started when the first 8-inch (203 mm) floppy drive was introduced in 1970. It was replaced by the 5.25-inch (133 mm) drive in 1976 and by the 3.5-inch (89 mm) "micro-floppy" in 1980. Initially, the floppy drive was single-headed and had a storage capacity of 322 kB. The disk was protected by a hard plastic jacket which increased its durability and made handling easier. Gradually, the drive became dual-headed and eventually reached today's 1.44 MB capacity (2 MB unformatted). The drive's height also decreased from an initial 51 mm to 25 mm.

In the floppy drive, a ceramic slider with a ferrite composite head on a hard ceramic slider is in continuous sliding contact with the flexible disk. The disk consists of a flexible 76 micron-thick polyethylene terephthalate (PET) coated on both sides with a micron-thick particulate magnetic coating, which is a bunch of magnetic iron oxide particles in a polymer matrix. To extend the life of the disk, the disk surface is lubricated.

An important part of the floppy disk is the cartridge with soft liners. It stabilizes disk rotation and protects it from mechanical damage. The liners (non-woven fabric) clean the disk.

Nowadays, the track density of a floppy disk is about 135 tracks per inch for 3.5-inch disk. This, clearly, represents the distant past of magnetic recording technology.

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