This chapter is obsolete, Floppy are not manufactured still 2008. As of the first PC, the floppy drive was installed. Indeed, the first XT did not comprise hard disks.
A floppy disk drive is made up:
One finds two formats of readers and 5 capacities (formatted) according to the format.
One can install two disk drives on only one controller (and only one controller). The readers are connected to the controller by a cable 34 wire. At the end of the cable, two wire are reversed. Reader called a: puts itself at the end, the reader B (second reader) in the central connector. This can nevertheless be reversed in the BIOS. Two types of connectors are generally established with each connections, for a reader 3"1/2 and for a reader 5"1/4. The use of the readers 5"1/4 disappeared since first 486.
Somme ZIP 100 MB of Iomega of the first generation use the controller of diskette. Moreover, the first tape readers (backup, safeguard) also used this controller. Currently, Zip are connected on the hard disk controller IDE (possibly SCSI). The bands use either a controller owner, or an interface SCSI, the latter being reserved for the safeguard network (on server) with the sights of the capacities of these bands (several tens of GB) for speed and as controller SCSI is already established at the beginning...
The floppy disks must also be announced in the setup PC (according to the type and the capacity). Attention that 486 and the lower uses a reader 5"1/4 in a: by default.