Evolution of Microprocessors

Transistor was invented in 1948 (23 December 1947 in Bell lab). IC was invented in 1958 (Fair Child Semiconductors) By Texas Instruments J Kilby. The first microprocessor was invented by INTEL(INTegrated ELectronics). 

Size of the microprocessor – 4 bit 

Name	Year of Invention	Clock speed	Number of transistors	Inst. per sec
INTEL 4004/4040	1971 by Ted Hoff and Stanley Mazor	740 kHz	2300	60,000

Size of the microprocessor – 8 bit 

Name	Year of Invention	Clock speed	Number of transistors	Inst. per sec
8008	1972	500 kHz	3500	50,000
8080	1974	2 MHz	6000	10 times faster than 8008
8085	1976 (16-bit address bus)	3 MHz	6500	769230

Size of the microprocessor – 16 bit 

Name	Year of Invention	Clock speed	Number of transistors	Inst. per sec
8086	1978 (multiply and divide instruction, 16-bit data bus and 20-bit address bus)	4.77 MHz, 8 MHz, 10 MHz	29000	2.5 Million
8088	1979 (cheaper version of 8086 and 8-bit external bus)			2.5 Million
80186/80188	1982 (80188 cheaper version of 80186, and additional components like interrupt controller, clock generator, local bus controller, counters)	6 MHz
80286	1982 (data bus 16bit and address bus 24 bit)	8 MHz	134000	4 Million

Size of the microprocessor – 32 bit 

Name	Year of Invention	Clock speed	Number of transistors	Inst. per sec
INTEL 80386	1986 (other versions 80386DX, 80386SX, 80386SL , and data bus 32-bit address bus 32 bit)	16 MHz – 33 MHz	275000
INTEL 80486	1986 (other versions 80486DX, 80486SX, 80486DX2, 80486DX4)	16 MHz – 100 MHz	1.2 Million transistors	8 KB of cache memory
PENTIUM	1993	66 MHz		Cache memory 8 bit for instructions 8 bit for data

Size of the microprocessor – 64 bit 

Name	Year of Invention	Clock speed	Number of transistors	Inst. per sec
INTEL core 2	2006 (other versions core2 duo, core2 quad, core2 extreme)	1.2 GHz to 3 GHz	291 Million transistors	64 KB of L1 cache per core 4 MB of L2 cache
i3, i5, i7	2007, 2009, 2010	2.2GHz – 3.3GHz, 2.4GHz – 3.6GHz, 2.93GHz – 3.33GHz

Generations of microprocessors: 

1. First-generation –
   From 1971 to 1972 the era of the first generation came which brought microprocessors like INTEL 4004 Rockwell international PPS-4 INTEL 8008 etc. 
   
2. Second generation –
   The second generation marked the development of 8-bit microprocessors from 1973 to 1978. Processors like INTEL 8085 Motorola 6800 and 6801 etc came into existence. 
   
3. Third generation –
   The third generation brought forward the 16-bit processors like INTEL 8086/80186/80286 Motorola 68000 68010 etc. From 1979 to 1980 this generation used the HMOS technology. 
   
4. Fourth generation –
   The fourth-generation came into existence from 1981 to 1995. The 32-bit processors using HMOS fabrication came into existence. INTEL 80386 and Motorola 68020 are some of the popular processors of this generation. 
   
5. Fifth-generation – 
   From 1995 till now we are in the fifth generation. 64-bit processors like PENTIUM, Celeron, dual, quad, and octa-core processors came into existence. 
   

Types of microprocessors :

• Complex instruction set microprocessor –
  The processors are designed to minimize the number of instructions per program and ignore the number of cycles per instruction. The compiler is used to translate a high-level language to assembly-level language because the length of code is relatively short and an extra RAM is used to store the instructions. These processors can do tasks like downloading, uploading, and recalling data from memory. Apart from these tasks, this microprocessor can perform complex mathematical calculations in a single command. 
  Example: IBM 370/168, VAX 11/780 
  
• Reduced instruction set microprocessor –
  These processors are made according to function. They are designed to reduce the execution time by using the simplified instruction set. They can carry out small things in specific commands. These processors complete commands at a faster rate. They require only one clock cycle to implement a result at uniform execution time. There is a number of registers and less number of transistors. To access the memory location LOAD and STORE instructions are used. 
  Example: Power PC 601, 604, 615, 620 
  
• Superscalar microprocessor –
  These processors can perform many tasks at a time. They can be used for ALUs and multiplier-like arrays. They have multiple operation units and perform tasks by executing multiple commands. 
  
• Application-specific integrated circuit –
  These processors are application-specific like personal digital assistant computers. They are designed according to proper specifications. 
  
• Digital signal multiprocessor –
  These processors are used to convert signals like analog to digital or digital to analog. The chips of these processors are used in many devices such as RADAR SONAR home theatres etc. 
  

  Features :

Clock speed: One of the earliest features of microprocessors was the clock speed, which refers to the speed at which the processor can execute instructions. Over time, clock speeds have increased, with modern processors capable of speeds in the billions of cycles per second (GHz).

Instruction set architecture: Microprocessors have evolved to support different instruction set architectures, including CISC (complex instruction set computer) and RISC (reduced instruction set computer), which affect the efficiency and complexity of processing.

Cache memory: Microprocessors now include a cache memory, which is a small amount of high-speed memory that stores frequently used data for quicker access.

Multi-core processors: Modern microprocessors have multiple cores, allowing for multiple tasks to be executed simultaneously, increasing performance and multitasking capabilities.

Virtualization: Microprocessors now support virtualization, which enables multiple operating systems to run on the same physical hardware.

Power management: Modern processors include power management features, which reduce power consumption and improve energy efficiency.

Graphics processing: Many modern microprocessors include integrated graphics processing units (GPUs), which allow for faster and more efficient handling of graphics-intensive tasks.

Security features: Microprocessors now include security features, such as hardware-level encryption and secure boot, to protect against malware and hacking.

Internet connectivity: Microprocessors now include built-in networking capabilities, such as Wi-Fi and Ethernet, which allow for seamless internet connectivity.

Machine learning capabilities: Some modern microprocessors include specialized processing units for machine learning and artificial intelligence tasks, allowing for faster and more efficient processing of these tasks.

Advantages of the microprocessor –

1. High processing speed
2. Compact size
3. Easy maintenance
4. Can perform complex mathematics
5. Flexible
6. Can be improved according to a requirement 
   

Disadvantages of microprocessors –

1. Overheating occurs due to overuse
2. Performance depends on the size of the data
3. Large board size than microcontrollers
4. Most microprocessors do not support floating-point operations