Methods and apparatus for selectively accessing a portion of a sterile cryopreserved sample are disclosed. Within the packet switch, separate devices are responsible for storing a portion of a received data packet, and thus a view of used memory addresses seen by one device matches that seen by the others. A substantially solid member is movably positionable adjacent the second flowpath for selectively blocking and unblocking portions of the second flowpath for defining a variably dimensionable flow path in order to control over the amount of oxygen flowing through the second flowpath. The controller selectively sends one of a video signal generated by processing the network packet stream and an external video signal to the display unit for displaying the received video signal, according to a control signal.