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Evolution of Microprocessor

First Generation Microprocessors: 
  • These were introduced between 1971 and 1973.
  • They were designed using PMOS technology.
  • This technology provided low cost, slow speed and low output currents.
  • They were not compatible with Transistor transistor logic (TTL) levels.
  • It required 30 ICs to form a system.
  • 4 bit processors were provided with only 16 pins.
  • 8 bit processors were provided with 40 pins.
  • Examples: INTEL 4004, NATIONAL IMP-4, INTEL 8008, etc.
Second Generation Microprocessors: 
  • They appeared in 1973.
  • They were designed using NMOS technology.
  • This technology provided fast speed and high density.
  • They were TTL compatible.
  • They provided more powerful instruction set.
  • They provided better interrupt handling capabilities.
  • Chip size larger and provided with 40 pins.
  • Examples: INTEL 8080, INTEL 8085, NATIONAL CMP-8, etc.
Third Generation Microprocessors: 
  • They were introduced after 1978.
  • These are 16 bit processors.
  • They were designed using High Density MOS (HMOS) technology.
  • This technology provided better speed and higher packing density.
  • They were provided with 40/48/64 pins.
  • They have strong processing capability and they are easier to program.
  • They also provide more powerful interrupt handling capabilities.
  • The processor has multiply and divide arithmetic hardware.
  • Examples: INTEL 8086, INTEL 8088, INTEL 80186, etc.
Fourth Generation Microprocessors: 
  • They were introduced in year 1980.
  • These are 32 bit processors.
  • They were designed using low power version of HMOS technology.
  • Physical memory space is 16 MB.
  • Virtual memory space is 1 TB.
  • Floating point hardware is incorporated.
  • They are supported by increased number of addressing modes.
  • Examples: INTEL 80386, INTEL 80486, MOTOROLA M68020, etc.
Fifth Generation Microprocessors: 
  • INTEL came out with a new processor namely Pentium processor.
  • They employed decoupled super scalar processing.
  • Their design exceeded 10 million transistors.
  • They provided high performance floating point operations.
  • They have high speed.
  • Examples: PENTIUM, PENTIUM II, PENTIUM III, PENTIUM IV.

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