The invention relates to data processing systems making use of an addressable memory. It proposes a process and system permitting qualifying terms to be associated with the data contained in the data memory by writing these qualifying terms at locations associated with the data within a qualifier and set aside for this purpose. These qualifying terms are characteristics of the data or the processing undergone by the data. The qualifier memory, which is interfaced with the processor as though it was a peripheral I/O device, uses an INTERUPT to alert the processor of the occurrence of a call on data which has an associated qualifier.
A computer system has a cache located between input/output devices and a main system memory. All system memory accesses by the input/output devices are made through the cache. Memory accesses through the cache are limited to those addresses which are accessible to a central processor and input/output devices. All access to such addresses by the central processor are made through the cache.
