This is commonly referred to as a "Berg connector", after it's original manufacturer, the Berg Electronics Corporation.
berg
not sure what it is called by name but it is a 4 pin plug most of the time.
Some examples are hard drives, CD drives, DVD drives, flash drives, zip drives, and floppy drives
because in the IBM PC drives a and b were dedicated to floppy drives.
Not sure what you mean by larger drives, but you are probably talking about a 4-pin.
Hard Drive, Floppy disk, Cd, DVD, flash drives...
20 pin P1 connector.
P1
=floppy bunnies==floppy bunnies==floppy bunnies=
DVD-ROMCD-ROMExternal hard diskfloppy diskpen drive
floppy drive
Floppy itself..