There's a short whitepaper published by HGST (now part of Western Digital) which discusses the history and benefits of the ramp load-unload mechanism [1]. [1]

There's a short whitepaper published by HGST (now part of Western Digital) which discusses the history and benefits of the ramp load-unload mechanism [1]. [1] http://www.hgst.com/tech/techlib.nsf/techdocs/9076679E3EE4003E86256FAB005825FB http://www.hgst.com/tech/techlib.nsf/techdocs/9076679E3EE400...