Abstract: A system is provided for the safe transfer of large data files over an unreliable network link in which the connection can be interrupted for a long period of time. In the subject system, the sender sends a file with a unique signature which is recognized by the receiver, with the signature providing information as to file size. Upon the occasion of an interrupted communication over the link, the receive side waits for another connection. Upon the establishment of the connection, the receive side recognizes the signature of the file as the f-ile which was being transmitted at the time of the interruption and requests blocks of data from the sender from the point at which the interruption occurred, with the point being established by the file size and the time of the interruption. The result is a restartable transfer of the transmission of information from the sender to receiver from the place where it left off, thus eliminating the annoyance of having to restart the transmission from the beginning.

Abstract: A system is provided to deliver complete files from a server to a maximum number of clients, while at the same time minimizing cumulative waiting time through the utilization of a prioritization heuristic in which there are two competing priorities. As to the first priority, the highest priority is given to those clients most in danger of not receiving a complete file by a predetermined deadline. The second priority is set to minimize the waiting time for the delivery of files by sending the files only to those clients that are capable of receiving the data fastest. An exponential curve system is utilized as a tie breaker between the two competing priorities in which the weight of each priority is determined. As a result, in terms of distribution from a single server to multiple clients, the calculation of the weighted priority is a real number derived from user parameters such as log-in characteristics, the due date, and the amount of the file remaining to be transmitted.

Abstract: A system is provided for the safe transfer of large data files over an unreliable network link in which the connection can be interrupted for a long period of time. In the subject system, the sender sends a file with a unique signature which is recognized by the receiver, with the signature providing information as to file size. Upon the occasion of an interrupted communication over the link, the receive side waits for another connection. Upon the establishment of the connection, the receive side recognizes the signature of the file as the file which was being transmitted at the time of the interruption and requests blocks of data from the sender from the point at which the interruption occurred, with the point being established by the file size and the time of the interruption. The result is a restartable transfer of the transmission of information from the sender to receiver from the place where it left off, thus eliminating the annoyance of having to restart the transmission from the beginning.