Abstract: A piston and chamber system to be used in connection with a heat concentrator such as those used for converting low grade thermal energy into useful energy. The example apparatus disclosed herein includes a heat engine floating piston which inhibits condensation normally associated with thermodynamic cycles which run at or near vapor saturation. The resulting improvement allows increased efficiency for lower temperature systems.

Abstract: In a packet data transmission system, correctly received information packets are acknowledged by piggybacking their sequence numbers onto information packets being transmitted. The control field of each information packet includes a bit which indicates whether or not there is a piggybacked acknowledgement. Acknowledgements can also be transmitted separately in control packets having no information field. Each acknowledgement consists of not only the sequence number of a correctly received information packet, but also the acknowledgement status of a plurality of preceding information packets whereby these can be negatively acknowledged if necessary. The sequence numbers can have any one of three different sizes, for efficient transmission of sequence numbers on transmission links of arbitrary transmission speed and length (and hence delay).

Abstract: In a bubble memory system having storage loop architecture, means for buffering both read and write requests in order to improve performance including, in the embodiment disclosed, two sets of short or buffer loops, one for the write section and one for the read section, which are virtually asynchronous with respect to each other and to the main memory storage loops and in which data may be temporarily stored prior to transfer into the main storage loops or prior to transfer into an output track.

Abstract: In a bubble memory system having storage loop architecture, means for decoupling the write-in means and the read-out means from the propagation cycle of the storage loops so that data may be transferred in and out of said storage loops independently of each other and of the propagation cycle thus decreasing the access time of a bubble memory.