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The highest-capacity format for floppy disks is the 2.88 MB 3.5" disk that was developed by Toshiba in the late 80s. The 2.88 MB offers double the capacity of the 1.44 MB disk by using special media and a special recording method.

If you've never used or even heard of this drive format before, then you are exactly right. :^) It is basically a dead format; I very rarely if ever see it used. The exact reason why is anybody's guess, but these three factors weigh heavily in my mind when I consider why it might be that nobody uses 2.88 MB floppies despite the fact that everyone hates the small size of the 1.44 MB floppy:

• Inertia: By the time the 2.88 MB went into full production, the PC explosion was well underway with a very large number of these existing machines using 1.44 MB disks. The 1.44 was the standard and so people were reluctant to use 2.88 MB disks because of the installed base of PCs that could not read them.
• Compatibility: The very high bit density of the 2.88 MB floppy--36 sectors per track--means that a floppy controller capable of 1 Mbits/s transfer rate is required. Many older PCs only had a controller capable of 500 Kbits/s transfers. Using the newer drive would have required a new controller card. (Virtually all new PCs are capable of supporting the 2.88 MB disk with no problem.)
• Media Cost: The media for these drives is very expensive. In fact, right now, 1.44 MB disks can be had for less than 50 cents each, and in some cases for free by using mail-away rebates. In contrast, 2.88 MB disks still cost several dollars a piece! Now, this is a bit of a chicken-and-egg thing, because if the disks aren't popular the production volume is low, and this will make the cost high, thus making the disks even less popular, and so on. However, it was probably a significant contributing factor to the 2.88 MB not catching on.

Of course the old standbys of "poor marketing" and "overpriced hardware" could have been contributing factors as well.

Note: Look here for specifications on all of the floppy disk formats.

Next: File System and Floppy Disk Structures

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