We will look at the floppy disk because although its mass uses are probably passed, it still performs certain functions that will be useful for a first line support technician to be aware of, e.g. it can still be used to boot a PC to allow a new operating system to be installed.
The floppy disk works in a similar way to the hard disk with the main difference being that only a single magnetic platter is used and that the read/write head actually make contact with the disk surface rather than float above it.
Floppy disk technology was pushed to the limits by the mid 1990's, when it was no longer possible to expand the amount of data that could be stored on the disk. This was due to the concept of coercivity, i.e. if data is stored in magnetic spots then how near can they be to each other without affecting what is stored. In the case of the floppy disk, more data could not be squeezed onto this surface because if it was it would interfere with the other data.
Probably the most common type of floppy disk was the 31/2-inch High Density Disk which could store up to 1.44 MB. Other variations appeared throughout the 1990's and pushed the storage capacity higher, however, by then other devices had started to erode the floppy market, e.g. flash drives
Click on this link to review the wiki resource on floppy disks.
Next: The CD-ROM Family