3.5-inch diskette

Updated: 11/13/2018 by Computer Hope

A 3.5-inch diskette was first created by IBM in 1984 with an initial capacity of 720 KB and later 1.44 MB that replaces 5.25" diskettes. These disks were the most commonly used methods to backup and store data in the 1990s, but by 2000 were seldom used or found with the introduction of CD-R discs and later USB thumb drives.

3.5-inch floppy diskette

The 3.5-inch floppy diskettes have dimensions of 8.9cm in width by 9.3cm in height and are referred to as floppies because of the circular magnetic floppy in the hard shell. 3.5-inch floppy diskettes come in sizes of 720 KB low-density, 1.44 MB high density capacity, and IBM even developed an extended density disk capable of holding 2.88 MB. The picture is a diagram of a floppy diskette and each of its major components.

Floppy write protect tab

In the diagram above, notice the small write protect tab. This tab enables the floppy disk to be switched from write-protected and unwrite-protected. Move the tab to the top position, creating a hole, makes the disk write protected. Moving the tab to the bottom position allows the disk to be non-write protected, which means the diskette can be written too, erased, or have information deleted from the diskette. Some cheaper disks may be missing this tab. To write information to the diskette, you have to place a piece of scotch tape over the hole.

High Density hole

Second, the top-right hand of the back of the floppy you will notice a small hole. If the drive mechanism detects that this hole exists, the computer knows it is a High Density diskette.

Middle of a floppy diskette

Third, the circular metal disk in the middle of the floppy diskette. This part rotates the magnetic medium in the floppy disk casing.

Read / write access door

Finally, there is a metal door that can be moved left and then will snap back to its original position. This door is allows the read/write head in the floppy drive to access the magnetic medium in the casing. Once the diskette is removed, this door will snap back into position, helping to prevent anything from getting on the magnetic medium and destroying it. The door also increases the longevity of the magnetic disk.

As seen in the picture below of a clear 3.5" floppy diskette, there is a circular cloth that is located on both sides of the floppy. This cloth helps clean and protect the magnetic disk in the diskette.

Clear 3.5" floppy diskette

Above is a clear floppy diskette and a real-life example of a floppy diskette. Today, the 3.5-inch diskette and drive has been replaced by CD-R discs and USB thumb drives.

5.25-inch floppy, Floppy drive terms