1. Memory hierarchy

1.1 General

"One instruction per second requires one byte of memory and 1 bit/s of I/O capacity" – empirical law formulated by G. Amdahl, famous mainframe designer at IBM and in his own company.

Translated to contemporary values, this empirical law would mean that a computer executing 1 GIPS (1 billion instructions per second) would need 1 GB of memory and 1 Gb/s of I/O capacity. This empirical law emphasizes the necessary relationship between the three essential components of a computer: the processor, main memory and I/O. This dossier details one aspect of this relationship: the memory hierarchy between the processor and main memory.

Computers use a main memory (MP) and secondary memories. These memories differ in terms of technology...