A computer system having a CPU which executes instructions and uses resources of the computer system as the instructions are being executed. A monitoring device of the computer system monitors the quantity of resources used by the execution device and outputs a signal indicating that a limiting threshold of the use of the computer system resources has been approached, reached, or exceeded. Once the system resource limiting threshold has been reached, the executing process in the CPU is interrupted and data associated with the executing program is saved in a first save area. If a user of the computer system does not take any action after a predetermined period of time, the saved data associated with the executing program is moved to a second save area which has a slower access time than the first save area. After another predetermined period of time has elapsed without input from the user indicating a resume of the previously executing program, the saved data is further moved to a different storage area having a slower access time than the second storage area. The saved data is used to restart the execution of the instructions which have been interrupted, upon the input of a restart command from a user, so that the computer does not have to re-execute the previously executed instructions.

A method and apparatus for notifying programs that a logical event has occurred on a network, said event being a power failure. Upon the occurrence of a logical event in an operating program, an alert report is generated and stored in a buffer. An alert function call occurs, providing the event type and a pointer to the buffer. The alert function call reads a look-up table listing the programs or users requesting notification of events. The look-up table provides the addresses to which notification should be sent and the type of notification requested. The alert subroutine sends the requested event data from the buffer to the listed addresses. The alert function is completed and the operating program resumes operation. Upon receiving the event report, the receiving program stores it, displays it to a user, generates additional reports, begins controlling network activities, or the like as directed by the receiving program. The invention provides the advantage that each operating program need only perform a universal function call to send event data through the network and then may return to a task. The operating program is not concerned with who receives the report or what action is taken based on the report. The programs requesting alert data from an operating program of any type need only provide a request to an alert look-up table. The sources of the events and requesting programs are all software controlled, providing ease in adding or modifying each.

An apparatus and method allows for starting and stopping of computer system clocks where the propagation length of signal paths exceed one clock cycle in length. A circular source buffer is provided at the source end of a signal path and saves the data presented on the signal path during every clock cycle. When the system clock has been stopped and is to be restarted, the data stored in the source buffer is copied to a corresponding destination buffer located in the destination end of the signal path. A multiplexer under hardware control located at the destination end of the signal path determines whether the destination receives data from the destination buffer or from the signal path.

A terminal apparatus having a data processing circuit wherein a reset command, which is sent from another station through the same transmission line and according to the same procedure as normal data sent from the station, is detected, and then the data processing circuit is reset in accordance with the reset command. Further, a data renewing command, which is also sent from another station through the same transmission line and according to the same procedure as normal data sent from the station, is detected, and then a content of a data storage in the terminal apparatus is renewed in accordance with the data renewal command.

A storage format and methods for improving the performance of the symbol table of an encoded vector index. The symbol table comprises a hash table, entries of the hash table storing associated key values and codes for the encoded vector index. Hash table entries store an accumulated count of occurrences of prior and the current key values, which improves the efficiency of responding to a request for a key range count. A binary radix tree is used to locate entries, which comprises a plurality of nodes, corresponding to binary digits of a binary representation of a key value. Codes are assigned to key values for the encoded vector index in a distributed fashion, so there are available code values between existing code values in the code ordering, that can be assigned to new key values, alleviating the need to reorganize the code values upon an insertion.