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. First microprocessor was invented by INTEL(INTegrated ELectronics).

Size of 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 microprocessor – 8 bit

Name Year of Invention Clock speed Number of transistors Inst. per sec
8008 1972 500 KHz 50,000
8080 1974 2 MHz 60,000 10 times faster than 8008
8085 1976 (16 bit address bus) 3 MHz 6500 769230

Size of 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 addtional components like interuppt 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 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 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 microprocessor:

  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 Mororola 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 minimise the number of instructions per program and ignore the number of cycles per instructions. 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 these microprocessor can perform complex mathematical calculation in a single command.
    Example: IBM 370/168, VAX 11/780

  • Reduced instruction set microprocessor –
    These processor 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 faster rate. They require only one clock cycle to implement a result at uniform execution time. There are 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

  • Super scalar microprocessor –
    These processors can perform many tasks at a time. They can be used for ALUs and multiplier like array. They have multiple operation unit and perform tasts my executing multiple commands.

  • Application specific integrated circuit –
    These processors are application specific like for personal digital assistant computers. They are designed according to proper specification.

  • 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.

Advantages of microprocessor –

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

Disadvantages of microprocessors –

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


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