Summary

This chapter focused on memory and cache, first explaining the differences between memory (dynamic RAM) and cache (static RAM).

The next topic was how memory works. This chapter covered DIMMs and SIMMs and how memory is used to store and retrieve data.

Several innovations have come about that have improved memory performance over the years. These innovations include FPM, EDO, SDRAM, DDR RAM, and interleaved memory.

As memory technologies have evolved, several factors have combined to increase the possibility of memory failures. The next topic focused on the various means by which memory can be made more tolerant to faults, including parity checking, ECC, and AECC. HP and Compaq have pioneered the development of more advanced memory technologies, including online spare memory, single-board mirrored memory, hot-plug mirrored memory, and hot-plug RAID memory. These advanced technologies are explained later in this book.

Finally, this chapter discussed how cache is used to enhance system performance and the various cache architectures and technologies.