An apparatus and method for block acknowledgements with reduced recipient state information are described. The handle assembly comprises a grip and a lever. Each computer may securely maintain and manage storage for other computers’ files. The door closing mechanism is a mechanical transmission that includes a set of linkages running from the door to a reciprocating pneumatic cylinder. The second wrap surface includes a second wrap surface texture that is different than the first wrap surface texture and a second wrap width that is less than the pitch.