Using Simulation to Develop and Port Software

Among the tools developed to support Digital's Alpha AXP program were four software simulators. The Mannequin and ISP instruction set simulators were used to port the OpenVMS and OSF/1 operating systems to the Alpha AXP platform. The Alpha User-mode Debugging Environment (AUD) allowed Alpha AXP user-mode code to be debugged with support from the OpenVMS VAX runtime environment on VAX hardware. AUD was built from a combination of new and existing Digital software components. The Alpha User-mode Debugging Environment for Translated Images (AUDI) allowed translated images to be debugged on a simulator running on a VAX computer. With these debugging environments, user-mode applications and code components could be tested before Alpha AXP hardware and operating system software were available.