Abstract: A computer system is selectively booted into an advanced configuration and power interface (ACPI) mode or a non-ACPI mode during computer system start-up, depending upon the status of a user specified flag. The instructions and data needed to boot the computer system into ACPI mode can be stored in a memory in a format not visible to the computer system operating system. A user can specify the desired boot mode through a user set-up routine.

Abstract: A microcomputer system with a data destination facility provides for accessing dynamic RAMs of different speeds faster or slower depending on the dynamic RAM speed. When the data destination facility maps the dynamic rams, it also saves a bit indicating whether the block of RAM is a high or low speed RAM. When the memory controller attempts to access a certain location, the data destination facility then returns the value of the speed bit associated with that block of memory to the memory controller state machine, which then omits or adds clock cycles to the memory access depending upon the speed of the memory. Further, in setting up the data destination facility, the system initialization routine determines SIMM sizes by first touching the memory locations at which the SIMMs are occupied to determine if there is memory there, and then determines the SIMM speeds based on a combination of the SIMM sizes and the SIMM identification codes returned through a standard serial shift register.