2.EVOLUTION OF MICROPROCESSORS

..When the storyteller recites the tales he must sing about those period of time when the heroes fall and new one arise...In the world of microprocessor also , this tale teller will make you walk through those phases to get a better understanding about transformations.We will start from where we have left our story....

EXIT OF  A HERO.

After the breakthrough of the first microprocessor 4004, Intel decided to expand its wings to other areas such that the usage of 4004 was boosted. The need for more advanced and developed Integrated chips began to make Intel think about the need to do research in this field.

The four bit microprocessor debuted in early video game systems and small microprocessor based control systems.Speed, word width and memory were the problems associated with the first microprocessor.

• » 4-bit microprocessor
• » 740 KHz
• » 4 KB program memory
• » 640 bytes data memory
• » 3-level deep stack
• » No interrupts

IN MEMORY OF THE LOST  HERO????

To control the inefficiencies of  4004 Intel came with the much more reliable and high speed 4040.When Intel introduced 4040 as  a new renewed version of 4004 there was no much improvements in the word width and memory size but it had high speed when compared to its successor.
In short 4040 had :

» 4-bit microprocessor

•     » 740 KHz
•     » 2 x 4 KB program memory
•     » 640 bytes data memory
•     » 7-level deep stack
•     » No interrupt
•    » 4004 object-code compatible

RISE OF A LEGEND...

In 1971 when Intel understood the market games, and made microprocessors a viable commercial product.

The constant motivation to gain the market lead Intel to advance with the research ideas.Intel released 8008 microprocessor.It addresses an expanded memory size 16KB and contained additional instructions that provided opportunity for its application in various fields.

• » 8-bit microprocessor
• » 16 KB memory
• » Interrupts

Even this new Hero could not satisfy the needs of the engineers when they began to make the full use of 8008.



A NEW FAMILY TAKES UP THE REIGN...

The impact lead of 8008 lead to the advent of  a new family of eights..8080,8800,8085.

8080 addressed more memory and executed additional instructions, that is about 10 times faster than 8008. Since 8080 was more compatible with TTL technology it made the interfacing process less expensive . 

Altier 8800 was a newcomer to this family. Developed by Bill Gates and Paul Allen in Microsoft it opened a new challenge to its colleagues.

8085 can be considered as the revised version of 8080. Although slightly more advanced than 8080 , it executed software at an even higher speed .The main advantage of 8085 was:the internal clock generator , internal system controller and high clock frequency. 

These improvements are responsible for ushering in the era of 8080 and continuing saga of the  microprocessor.

RULES CHANGES THUS THE TALE..

The rules changed and thus the phase of transition.The arrival of 80286,32 bit microprocessors,80486,pentium processors were the predecessors.

80286 MICROPROCESSOR

It was a 16 bit architecture microprocessor and is identical to 8086 and 8088.The main difference was in the memory addressed by the system.It addressed about 16M-byte of memory and thus increasing the speed of execution and instruction sets.

Some changes were made at internal execution of the instructions, which led to an eight fold increase in speed for many instructions when compared to 8086/8088 instructions.

32-BIT MICROPROCESSORS 

Applications began to demand faster microprocessor speed, more memory and wider data paths.This lead to the emergence of 80386 in 1986.It was the first practical 32-bit microprocessor that contained 32 bit data bus and 32-bit memory address.Thus upto 4G bytes of memory were addressed.Its also called an Embedded PC because it had all the components that a AT class personal computer on  a single integrated circuit.

80486 MICROPROCESSORS

In 1989 Intel released its 80486 microprocessor which incorporated 80387 like numeric processor and 80386 like microprocessor and an 8K byte cache memory.The internal structure of the 80486 was modified from the 80386 so that about half of its instructions executed in one cycle instead of two.

PENTIUM PROCESSORS

The pentium processors were developed by Intel in 1993 , keeping in mind to combine the 80386 and 80486 microprocessors.It was actually denoted as P5 ot 80586.The major improvements were in the cache size where 16K bytes of cache can be seen.The world had still too much to witness after the rise of Pentium.To understand in detail we must travel to the core.

.........When we all think that the tale ends here..at this point....Be aware about the games of destiny. Because the tale has not yet started ,this was just giving you an idea about the place where I am taking you..I am leaving you here at this cliff hanger..until then lets enjoy the tales of microprocessors.But promise you to take  to the real world of microprocessors..which lay hidden from behind the shadows.........