Standalone Package-Based Diagnostics

Diagnostics that are performed before the OS is booted can assume complete control of a subsystem or system’s resources. These diagnostics support the most thorough testing of components, because the diagnostics control all the resources being tested. However, the effort to write the code to manage all resources being tested, while providing fine-grained control, can be quite complex (effectively a light-weight OS tailored to testing). To avoid development of such a complex infrastructure, pre-OS diagnostics might provide thorough, targeted testing of components in isolation.

Standalone diagnostics are typically run in manufacturing or at a customer site during a new system installation. In this environment the diagnostics can be run without being concerned about corrupting or destroying customer data. Diagnostics can also assume that there are no restrictions on resource utilization (for example, they can force CPU or I/O boundary conditions to achieve effective testing) since the systems are not in use by customers.