A KeyDrive is basically a bit of flash memory with a USB interface. They're roughly as large as a thumb and perfect for carrying one around on your keychain - hence the name. Their capacity is commonly 128MB, which makes them a more sensible contemporary means of transporting data than floppy disks would be. You can even boot from one, if your BIOS knows how to talk to them.
LinuxDistributions bootable directly from a KeyDrive include
FlonixLinux KeyPuppy, a cuckoo? and pluralmedia? 
distro that doesn´t need own partion?).There are also LiveCDs such as Mandrake Move that can use a KeyDrive to make your home directory and other configuration data persistent.
See also:
7 pages link to KeyDrive:
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