Abstract: A new system for simulation of electrical circuits and devices over a network is disclosed. The system consists of at least a client computer, a server computer, a network that connects them (including intermediate proxy servers and routers) and software methods. New software methods are disclosed that combine client-submitted data from the internet with template data, simulate the combined data using a simulator such as SPICE and create display and other data for transport to and display on the client computer. Additional methods are disclosed relating to circuit synthesis prior to simulation, access control, limiting resource use and abuse, expiration of temporary files and identifiers and usage logging.

Abstract: Systems, methods and computer media instructions are disclosed that enable the storage or caching of server account information by a client application, such as a web browser with the ability to store “cookies”. The account information is used to control access to server resources. Server methods update, then verify client-stored account information before beginning an operation and optionally credit the account for cancelled or failed operations. The account is preferably stored encrypted or obfuscated to prevent user modification. Additional methods are disclosed for the use of a “sampling” database and/or log comparison to deter abuse of these systems, methods and instructions.