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

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

3. 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

4. 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

5. 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

6. 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

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

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

9. 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

10. 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

11. 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

12. 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