Q. Fundamental building block of main memory?
The fundamental building block of main memory remains DRAM chip as it has for decades. Till recently there had been no important changes in DRAM architecture as early 1970s. The conventional DRAM chip is constrained both by its internal architecture as well as by its interface to processor's memory bus. The two techniques which currently dominate the market are SDRAM and RDRAM. A third one which is Cache RAM is also very popular.