Microdrive

Microdrive (MD) is a brand name for miniature, 1-inch hard disks designed to fit in CompactFlash (CF) Type II slots. The release of similar drives by other makers led to them often being referred to as `microdrives`. As of 2011, Microdrives are viewed as obsolete, having been eclipsed by solid-state flash media in read/write performance, storage.....
Found on http://en.wikipedia.org/wiki/Microdrive

Microdrive

(Digital cameras and photo printers) A miniature hard drive from IBM that fits the Compact Flash Type II format. To record images to a Microdrive, a digital camera not only needs to be compatible with Compact Flash Type II, but also electronically compatible (able to provide the power required and have the necessary firmware.)
Found on http://www.encyclo.co.uk/local/20472

Microdrive

IBM/Hitachi mini hard disk drive for digital cameras and PDA devices. Packaged in a CompactFlash Type II housing and available in 170MB, 340MB, 512MB, 1GB, 2GB, 4GB and above as the years progress!
Found on http://www.all-things-photography.com/digital-dictionary.html
No exact match found