Abstract: The present invention is directed toward a system and method for server back-up. A set of Primary servers and at least on secondary server is coupled to a set of networks. Each server has a host file module for assigning it a common node name and a unique node name. Each server has a high availability module for transmitting a server status over a network. The primary servers each have a set of services operating on their respective networks. The secondary server has a duplicate set of each service running on each primary server. Upon detecting a primary server status which indicates that a primary server is inoperative, the secondary server starts the duplicate set of the primary set of services corresponding to the now inoperative primary server.

Abstract: Interface unit for handling translation of message signals between a communication channel and a communications processor. The processor and interface unit are embodied in a data processing station of which a plurality of such stations are arranged along the communication channel. The interface unit includes a microstate machine which under program control directs the operations of message transmission, message receipt, and communication channel contention.

Abstract: An all digital method and apparatus for recovering NRZ information from MFM data wherein the MFM pulse stream is monitored through hypothetical windows, the receipt of a pulse during a particular window providing information about the data state(s) represented by the pulse and tracking adjustments required to recover subsequent pulses, and further wherein each window is divided into a large number of subinterval's so that the coincidence of a pulse with a particular subinterval provides information about the amount and direction by which the position of subsequent windows should be changed for tracking correction; the windows and subintervals being implemented by the execution of one of a number of step sequences, the particular step sequence being executed indicating the classification of a pulse received during the particular step sequence, and the step being executed at the time of receipt of the pulse indicating required tracking adjustments.