HISTORY OF MICROPROCESSORS
The invention of Integrated circuits in 1958 by Jack Kilby of Texas Instrument made a revolution in electronic circuitry. The use of ICs made the size of computers very small and became more versatile in functions. Finally, the advent of IC technology leads to the development of first microprocessor (INTEL 4004) in 1971 at Intel Corporation by an engineer Marcian E. Hoff.
First Generation
It was a 4-bit microprocessor – a programmable controller on a chip. This was called the first generation microprocessor. It was fabricated using P-channel MOSFET technology and had an instruction set of 45 different instructions.
A few first generation microprocessors are listed here
| 4-bit Microprocessor |
|---|
| INTEL 4004 |
| INTEL 4040 |
| FAIRCHILD PPS-25 |
| ROCKWELL PPS-4 |
| NATIONAL IMP-4 |
Application :
Most of the early 4-bit microprocessors were used almost exclusively in calculators and toys,later on for various utilities,video games,controllers,and early computers.4 bits was a logical choice for many calculators that used BDC numbers representation.
Second Generation
It was a 8-bit microprocessor.This was called the second generation microprocessor. It was fabricated using NMOS-technology which offered faster speed, higher density.
A few second generation microprocessors are listed here
| 8-bit Microprocessor |
|---|
| INTEL 8008 |
| NATIONAL IMP-8 |
| ROCKWELL PPS-8 |
| AMI 7200 |
| MOSTEK 5065 |
| INTEL 8085 |
| MOTOROLA M6800 |
| SIGNETICS 2650 |
The advantages of second generation microprocessor
- Larger chip size
- More powerful instruction set
- Faster operation
- Better Interrupt handling capabilities
- Ability to address larger memory space
Application :
Most of the early 8-bit microprocessors were used in many military applications,scientific instrumentation. complex control and processing system.
Third Generation
These were 16-bit microprocessors, designed using HMOS (High Density MOS) technology. These microprocessors offered better speed and higher packing density than NMOS.
A few third generation microprocessors are listed here
| 16-bit Microprocessor |
|---|
| INTEL 8086 |
| INTEL 8088 |
| INTEL 80186 |
| INTEL 80286 |
| MOTOROLA-68000 |
| MOTOROLA-68010 |
| NATIONAL NS-16016 |
| INTERSIL 6100 |
| ZILOG Z-8000 |
The advantages of third generation microprocessor
- High speed and very strong processing capability
- Easier to program
- Allow for dynamically re-locatable programs
- Size of internal registers were 8/16/32 bits
- Physical memory space was from 1 to 16 Mega-bytes (MB)
- More powerful interrupt and hardware capabilities
- Segmented address and virtual memory features
Application :
In the context of IBM PC compatible and Wintel platforms, a 16-bit applications is any software written for MS-DOS or early versions of Microsoft Windows which originally ran on the 16-bit intel microprocessor.
Fourth Generation
These were 32-bit microprocessors,These microprocessors are of low power version of HMOS technology.
A few third generation microprocessors are listed here
| 32-bit Microprocessor |
|---|
| INTEL 80386 |
| INTEL 80486 |
| MOTOROLA M-68020 |
| MOTOROLA M-68030 |
Fifth Generation
Fifth generation microprocessor was introduced by INTEL Corporation in 1993 in the form of PENTIUM with 64 data bus. The Pentium was similar to the 80386 and 80486 microprocessor. The two introductory versions of the Pentium operated with a clock frequency of 60 MHz and 66 MHz and a speed of 110 MIPS (Million Instructions Per Second). With better and more advanced technologies, the speed of μPs has increased tremendously. The old 8085 of 1977 executed 0.5 million instruction/sec. (0.5 MIPS), while the 80486 executes 54 million instruction per sec.
Sixth Generation
The Pentium Pro Processor is the Sixth generation microprocessor introduced in 1995 having better architecture but more in size. The Pentium Pro Microprocessor contains 21 million transistors, 3 integer units as well as a floating unit to increase the performance of most software. The basic clock frequency is 150 MHz and 166 MHz.