Microelectronics. Moore s Law. Initially, only a few gates or memory cells could be reliably manufactured and packaged together.

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1 Microelectronics Initially, only a few gates or memory cells could be reliably manufactured and packaged together. These early integrated circuits are referred to as small-scale integration (SSI). As time went on, it became possible to pack more and more components on the same chip. 37 Moore s Law Gordon Moore, cofounder of Intel, propounded Moore s law in According to Moore s law number of transistors on a chip will double every year. Since 1970 s development has slowed a little. Number of transistors doubles every 18 months. The consequences of Moore law are philosophical: Cost of a chip has remained almost unchanged. Higher packing density means shorter electrical paths, giving higher performance. Smaller size gives increased flexibility. Reduction in power and cooling requirements. Fewer interconnections increases reliability. 38 Growth in CPU Transistor Count 39 IBM System/360 In 1964, IBM replaced 7000 series with the System/360 family. 360 product line was incompatible with older IBM machines. System/360 was the industry s first planned family of computers. The models were compatible in the sense that a program written for one model should be capable of being executed by another model in the series. 40

2 IBM System/360 The characteristics of a family are as follows: Similar or identical instruction sets. A program that executes on one machine will also execute on any other. Similar or identical operating system. Increasing speed. Increasing number of I/O ports. (i.e. more terminals). Increased memory size. Increased cost. 41 IBM 360 Family 42 DEC PDP-8 In 1964, Digital Equipment Corporation (DEC) produced PDP-8. PDP-8 was the first minicomputer. was small enough to sit on a lab bench. did not need air conditioned room. used bus structure that is now virtually universal for minicomputers and microcomputers. 43 DEC PDP-8 PDP-8 bus is called Omnibus consists of 96 separate signal paths, used to carry control address data signals Console Controller CPU Main Memory OMNIBUS I/O Module I/O Module 44

3 DEC PDP-8 45 Generations of Computer Generation 1: Vacuum tube Generation 2: Transistor Generation 3: Small scale integration on Up to 100 devices on a chip Generation 3: Medium scale integration - to ,000 devices on a chip Generation 4: Large scale integration , ,000 devices on a chip Generation 5: Very large scale integration to date 100, ,000,000 devices on a chip Generation 5: Ultra large scale integration Over 100,000,000 devices on a chip 46 Generations of Computer 47 Semiconductor Memory Integrated circuit technology was also used to construct memories. Initially, magnetic-core memory was used as computer memory. Magnetic-core memory was fast expensive bulky used destructive readout (act of reading a core erase data stored). In 1970, Fairchild produced semiconductor memory. This chip was about the size of a single core could hold 256 bits of memory was nondestructive much faster than core 48

4 Microprocessors: 4004 In 1971, Intel developed its 4004 which was the first chip to contain all of the components of a CPU on a single chip: microprocessor can add two 4-bit numbers. 49 Microprocessors: 8008 In 1972, Intel developed 8008 which was the first 8-bit microprocessor. 50 Microprocessors: and 8008 had been designed for specific applications. In 1974, Intel developed 8080 which was the first generalpurpose microprocessor was an 8-bit microprocessor. 51 Microprocessors: 8086 At the end of 1970s, general-purpose 16-bit microprocessors appeared. One of these was

5 Microprocessors In 1981, Bell Labs and Hewlett-Packard developed 32-bit single-chip microprocessors. In 1985, Intel introduced its own 32-bit microprocessor, Evolution of Intel Microprocessors 54 Evolution of Intel Microprocessors 55 Microprocessor Speed In microprocessors, the addition of new circuits and the speed boost that comes from reducing the distance between them has improved performance four- or fivefold every three years or so since Intel launched its x86 family in But the raw speed of microprocessor will not achieve its potential unless it is fed a constant stream of work to do in the form of computer instructions. 56

6 Microprocessor Speed Some techniques to have more elaborate ways of feeding instructions quickly enough are as follows: Branch prediction. Branch prediction increases the amount of work available for the processor to execute. Data flow analysis. This prevents unnecessary delay. Speculative execution. This enables the processor to keep its execution engines as busy as possible by executing instructions that are likely to be needed. 57 Performance Mismatch While processor power has raced ahead at breakneck speed, other critical components of computer have not kept up. Processor speed and memory capacity (density) have grown rapidly. The speed with which data can be transferred between main memory and processor has lagged badly. 58 Performance Mismatch 59 Solutions There are a number of ways that a system architect can attack this problem. Examples include: Increase number of bits retrieved at one time by making DRAM wider by using wide bus data paths. Change DRAM interface to make it more efficient by including a cache. Reduce frequency of memory access by using more complex cache and cache on chip. Increase interconnection bandwidth between processors and memory by using higher speed buses and hierarchy of buses to buffer and structure data flow. 60

7 Design for performance I/O devices also become increasingly demanding. These devices create great data throughput demands. While processors can handle data pumped out by these devices, there remains the problem of getting that data moved between processor and peripheral. Some solutions: Caching and buffering schemes. Use of higher-speed interconnection buses and more elaborate structuring of buses. Use of multiple-processor configurations. 61 Design for performance Key is balance. Because of constant and unequal changes in: processor components main memory I/O devices interconnection structures designers must constantly attempt to balance their throughput and processing demands. 62 Pentium Evolution In terms of market share, Intel has ranked as the number one maker of microprocessors for decades. The evolution of its flagship microprocessor product serves as a good indicator of the evolution of computer technology in general. It is worthwhile to list some of the evolution of the Intel product line: 8080 First general purpose microprocessor. An 8-bit machine with an 8-bit data path to memory. Used in the first personal computer Altair. 63 Pentium Evolution 8086 Much more powerful. 16-bit machine. Instruction cache, prefetch few instructions before they are executed. A variant of this processor, 8088 (8 bit external bus) used in the first IBM PC MByte memory addressable instead of 1MByte Intel s first 32-bit machine. Support for multitasking, meaning it could run multiple programs at the same time. 64

8 Pentium Evolution Sophisticated powerful cache and instruction pipelining (a processor organization in which processor consists of a number of stages, allowing multiple instructions to be executed concurrently). Offers a built in maths co-processor, offloading complex math operations from main CPU. Pentium Introduce the use of superscalar techniques which allows multiple instructions executed in parallel. Pentium Pro Increased superscalar organization. Aggressive register renaming, branch prediction, data flow analysis and speculative execution. 65 Pentium Evolution Pentium II Incorporated MMX technology which is designed specifically to process graphics, video & audio processing. Pentium III Incorporates additional floating point instructions for 3D graphics. Pentium 4 Includes further floating point and multimedia enhancements. Itanium Makes use of 64-bit organization. 66 Intel Intel

9 Intel Pentium 70 More Pentium Pro III IV 71 Itanium 72

10 PowerPC IBM produced the PowerPC architecture. The following are the principal members of the PowerPC family: 601 Purpose is to bring PowerPC architecture to market as quickly as possible. A 32-bit machine. 603 A 32-bit machine. Comparable in performance with 601 but with lower cost and a more efficient implementation. 604 A 32-bit machine. Uses much more advanced superscalar design techniques to achieve greater performance. 73 PowerPC 620 Intended for high-end servers. Implemented with a full 64-bit architecture, including 64-bit registers and data paths. 740/750 Known as G3 processor. Integrates two levels of cache in main processor chip, providing significant performance. G4 Increases parallelism and internal speed of the processor chip. 74 PowerPC G4 75