1. A method for protection of a computer system's marking store, comprising the steps of executing a plurality of reading and writing processor operations for data processing by a computer system having a plurality of core processors and a marking store for a memory controller with hardware and firmware control, including writing in a processor operation of a processor of computer system to said computer system's marking store with a slow Error Correcting Code (ECC) decoder, and continuing during said processor operations said data processing, and reading marking store data with a read operation said computer system's marking store with a fast ECC decoder said computer system's marking store with a fast ECC decoder during said data processing by said processor operations, and notifying said memory controller firmware control when the computer system's marking store has been updated to lock writing to the computer system's marking store until controller firmware has read any updates of the computer system's marking store during said data processing of said processor operations.