1. ctalarico@ewu.edu1 Computing Systems Computer abstractions and technology

2. 2 Introduction Computer design is a rapidly changing field vacuum tube  transistors  VLSI circuits Memory capacity is doubling almost every 1.5 years Processor performance is improving 1.5-1.6 times per year Moore’s Law: the transistor count for an IC doubles every 18-24 months Learning objectives How computer works How to analyze their performance How hardware and software organization and design affect the performance Learning Motivation You want to design a computing system You want to write software that people use (need performance) You need to make a purchasing decision or offer and “expert” advice You want to call yourself a computer or electrical engineer

3. 3 What is a computer ? Different types: desktop, servers, embedded devices Different applications: automobiles, graphics, finance, genomics, … Different manufacturers: Intel, Apple, IBM, Microsoft, Sun, … Different underlying technologies and different costs!

4. 4 Computers in perspective Each time the cost of computing improves applications that were economically infeasible suddenly become practical Advance in computer technology affect almost every aspect of our society ENIAC (circa world war II)

5. 5 The computer market

6. 6 Embedded computers Anti-lock brakes Auto-focus cameras Automatic teller machines Automatic toll systems Automatic transmission Avionic systems Battery chargers Camcorders Cell phones Cell-phone base stations Cordless phones Cruise control Curbside check-in systems Digital cameras Disk drives Electronic card readers Electronic instruments Electronic toys/games Factory control Fax machines Fingerprint identifiers Home security systems Life-support systems Medical testing systems Modems MPEG decoders Network cards Network switches/routers On-board navigation Pagers Photocopiers Point-of-sale systems Portable video games Printers Satellite phones Scanners Smart ovens/dishwashers Speech recognizers Stereo systems Teleconferencing systems Televisions Temperature controllers Theft tracking systems TV set-top boxes VCR’s, DVD players Video game consoles Video phones Washers and dryers and the list goes on and on …

7. 7 The Computer components A computer is composed of five basic components: Input Output Memory Datapath Control Processor (= CPU)

8. 8 Hardware/software interface The hardware in a computer can only execute extremely simple low-level instructions. To go from a complex application to the simple instructions involves several layers of software that interpret or translate high level operations into simple computer instructions. These layers of software are organized primarily in a hierarchical fashion System software: operating system, compilers and assemblers

9. 9 Levels of abstraction An abstraction omits unneeded detail, helps us cope with complexity High level programming languages offer several benefits Allow the programmer to think in a more natural language Improve the programmer productivity Allow programs to be independent

10. 10 Levels of abstraction 1970198019902000+ Abstraction Transistor Level Gate Level RTL RT Level (HDL) RTLSW System Level

11. 11 Instruction Set Architecture (ISA) ISA (or simply architecture): - one of the most important abstraction - interface between the hardware and the lowest level software - standardizes instructions and machine language bit patterns Advantage: - Keeping the architecture as a constant enables many implementations of varying cost and performance to run identical software Disadvantage: - maintaining the architecture may preclude introducing innovations that require the interface to change Modern instruction set architectures: - IA-32, PowerPC, MIPS, SPARC, ARM, …

12. 12 The chip manufacturing process

13. 13 Internal structure of a processor chip Pentium 4 microphotograph

14. 14 The BIG Picture Both hw and sw consist of hierarchical layers, with each lower layer hiding details from the level above This principle of abstraction is the way both hardware designers and software designers cope with complexity One key interface between levels of abstraction is the ISA – the interface between the hardware and low level software. Key technologies for modern processors are silicon and compilers The rapid advance of silicon technology and new ideas in the organization of computers (e.g. exploiting parallelism via pipelining and exploiting locality of accesses via memory hierarchy) have improved price/performance

15. 15 Performance Both Hardware and Software affect performance: Algorithm determines number of source-level statements Language/Compiler/Architecture determine machine instructions (Chapter 2 and 3) Processor/Memory determine how fast instructions are executed (Chapter 5, 6, and 7)