Editing Diagnostic Serial Console (section)

=== Automatic Memory Detection and Configuration ===

During Power-On Self Test (POST), the Glue Logic (UI8) initiates system reset and address decode validation while the 68030 CPU performs basic memory access at reset vectors. The memory controller validates SIMM presence and configuration, followed by System ROM execution of built-in diagnostic routines and video memory allocation reserving 1MB from the available RAM pool. Bank detection and validation occurs automatically for installed SIMM configuration, with memory allocation optimization based on available modules and address bus integrity testing through POST sequences.

The diagnostic system reports memory configuration through hexadecimal codes that reflect addressing architecture. A typical 4MB configuration produces the diagnostic code <code>004000000000</code>, where the significant portion <code>00400</code> converts to 4,194,304 bytes (exactly 4MB). The trailing zeros <code>0000000000</code> likely represent diagnostic status information, error flags, or formatting padding used by Apple's diagnostic tools rather than additional memory size data.