Itanium Rising: Breaking Through Moore's Second Law of Computing Power

Memory Hierarchy Control

EPIC allows you to exercise much more control over the memory hierarchy. Memory exists in a hierarchical fashion on the machine. The registers are the fastest and closest to the microchip but also the smallest piece of memory. Next in line is what's known as the level 1 cache, which can also exist on the chip. It's fast, though not as fast as registers. The next fastest memory is the level 2 cache. This level can exist on the same chip, though it also may be based on a chip-on-a-chip module.

Further down the line is the level 3 cache, and at the bottom of the hierarchy is the disk drive itself. As you continue down the hierarchy, each level of memory gets bigger, though the access time gets slower. This is a function ...