The LS-120 (commonly known as the superdisk) was one of the suggested floppy-replacements that never caught on. First generation LS-120 drives used the standard 40-pin IDE interface. Although the poor performance was rectified in later generations, the LS-120 was never able to shake off its reputation for being slow. In contrary to the somewhat more common ZIP drive, the Superdisk drive is compatible with standard floppies though not all Superdisk drives are compatible with all 3 standard floppy densities.
The older Superdisk drives were more or less incompatible with Windows XP, making Windows 2000 and Windows ME the last Windows OS's with which the older drives could be used.
The most common version of the Superdisk drive was the standard IDE drive, which in theory meant that standard floppies could be read on a motherboard which doesn't have a working floppydrive controller.
As the name implies, the LS-120 disk could hold upto 120MB of data. An LS-240 drive was also made. In addition to being compatible with the 240MB version of the Superdisk, it remained compatible with standard floppies and it had the additional option to write around 32MB of data to a normal floppy (these specially formatted floppies could not be read in standard floppy drives however).