Abstract: A system for generating and maintaining lock files to inhibit conflicting requests for data files. A first process that accesses a data file generates a lock file to prohibit other processes from reading and/or writing that data file. Periodically the first process refreshes the lock file so that it shows a new modification time. A second process requesting access to the data file detect the lock file, stores the time of the attempted access, then waits a predetermined wait period and reads the lock file again. This is repeated, each time waiting for the wait period and again reading the lock file, until either (1) a predetermined time-out period passes without the first process refreshing the lock file, whereupon it is presumed that the process is defunct so the second process may access the data file; or (2) more than a maximum allowed access period of time has passed without the second process gaining access, i.e. the first process continues to refresh the lock file for greater than some predefined period.

Abstract: A method and related system for use with an interactive computer for invocation of a computer tool. A tool template and a tool encapsulator are provided for the tool. A tool template is a predetermined representation of processes and data employed to convey program status information to the user and to allow the user to control the program as it executes. In a specific embodiment, a tool template has a plurality of graphical constituents allowing a user to specify data and parameters, to invoke a program, to control execution of the program and to observe execution of the computer program. A tool template is to be used in connection with an encapsulator to allow a user graphical access to data through a display screen. Data is stored in an elementary unit called an object, each object being assigned a "data kind" to indicate the type of data that is contained within the object. Each object is graphically represented on a display by an icon which is determined by the object's data kind.

Abstract: Methods and apparatus for improving the servicing of an elevator system based upon the actual usage of its many functions. The usage of predetermined elevator system functions is monitored and data is collected relative thereto. Threshold and limit parameters are provided for the monitored functions, which parameters are periodically compared with the usage data. The reaching of a usage threshold parameter by a monitored function results in predetermined associated maintenance services being added to a maintenance due list. When a monitored function reaches its associated limit parameter, a need for scheduled elevator preventive maintenance is indicated for all of the maintenance services on the maintenance due list.