Resumen
This article examines why bandwidth improves much more quickly than latency. The article discusses six reasons why this imbalance occurs, and notes that caching, replication, and prediction help cope with it. It identifies four to six performance milestones over the last 20 to 25 years for microprocessors, memory, networks, and disks. The microprocessor milestones are six generations of IA-32 processors, going from a 16-bit bus, microcoded 80286 to a 64- bit bus, superscalar, out-of-order execution, superpipelined Pentium 4. Memory module milestones go from 16-bit wide, plain DRAM to 64-bit wide double data rate synchronous DRAM. Ethernet advanced from 10Mbps to 10Gbps. Disk milestones are based on rotation speed, improving from 3600RPM to 15000RPM. bandwidth and latency for each of those milestones. Performance is the primary differentiator for microprocessors and networks, so they have seen the greatest gains: 1000-2000X in bandwidth and 20-40X in latency. Even in the performance-oriented versions of memory and storage, capacity improves more rapidly than bandwidth.