Computer Architecture Part I-A: Fundamentals of Design Computer Architecture

Computer Architecture The Food Chain Big Fishes Eating Little Fishes Computer Architecture

Computer Food Chain Now who is eating whom? Mini- supercomputer Mini- Massively Parallel Processors Mainframe Work- station PC Server Supercomputer Now who is eating whom? Computer Architecture

Computer Architecture Why such a change? Performance Technology advances Computer architectural advances improves low-end Cost Simpler development Higher volumes Function Rise of interconnection technology Computer Architecture

Technology Trends: Microprocessor Capacity “Graduation Window” Alpha 21264: 15 million Pentium Pro: 5.5 million PowerPC 620: 6.9 million Alpha 21164: 9.3 million Sparc Ultra: 5.2 million Moore’s Law CMOS improvements: Die size: 2X every 3 yrs Line width: halve / 7 yrs logic capacity: 30%/year clock rate: at least 20% per year Computer Architecture

Technology Trends Summary Memory DRAM capacity: about 60% per year memory speed: about 10% per year cost per bit: improves about 25% per year Disk capacity: about 60% per year Computer Architecture

Computer Architecture Performance Trends Supercomputers Mainframes Minicomputers Log of Performance Microprocessors Y ear 1970 1975 1980 1985 1990 1995 Computer Architecture

Processor Performance (SPEC) 1.35x before, 1.58x now (about 2x every 1.5 years) RISC introduction Computer Architecture

Computer Architecture The Designer’s Task Technology Programming Languages Applications Computer Architecture Operating History/Applications matters because 1) People buy computers to run programs 2) Most people don;’t write own programs 3) Documented IDA interface means people ship binary machine code Systems History Determine the attributes needed for a new machine, then design a machine to maximize performance while staying within cost constraints Computer Architecture

Computer Architecture Functionality Designers must design a computer to meet functional requirements as well as price and performance goals. Application - How will the machine be used? Operating System - Which OS to support? Software - Will there be software for this machine? Will it be compatible with existing software? Standards - Should the new machine adapt or challenge existing standards? Computer Architecture

Computer Architecture Software vs. Hardware Each feature can be implemented either through hardware or software. A hardware implementation is not necessarily faster than a software one. There must be balance between these two implementations to meet performance and cost goals. Computer Architecture

Designing Through Trends The designer must take notice of: hardware trends, especially the rapidly occurring changes in implementation technology software trends and how programs will use the machine The designer must understand the impact of these trends on machine design. Computer Architecture