Fair child semiconductors (founded in 1957) invented the first Integrated Circuit in 1959 that marked the microprocessor history. In 1968, Gordan Moore, Robert Noyce and Andrew Grove resigned from the Fair child semiconductors and started their own company: Integrated Electronics (Intel). In 1971, the first microprocessor Intel 4004 was invented. A microprocessor is also known as a central processing unit in which numbers of peripherals’ are fabricated on a single chip. It has ALU (arithmetic and logic unit), a control unit, registers, bus systems and a clock to perform computational tasks.
This was the period during 1971 to 1973 of microprocessor’s history. In 1971, INTEL created the first microprocessor 4004 that would run at a clock speed of 108 KHz.With only 4 bits as the word size, the 4004 could only represent signed numbers in the range -8 to +7, which is indeed very small. So, it was not really of practical use for arithmetic calculations. However, it found applications in controlling devices.
Intel 8008 was the next in the evolution, the first 8-bit microprocessor. This was in the year 1972. This was soon followed by Intel 8080, also an 8-bit microprocessor. Intel 8080 was the first commercially popular 8bit microprocessor. With 8 bits as the word size, it could represent signed numbers in the range of −128 to +127. This is also not a good enough range for performing arithmetic calculations. Thus, the 8080 also was used only for control applications.
Some other microprocessors like 6800 from Motorola, Z-80 from Zilog were also Popular at this time.
They were costly as they were based on NMOS technology fabrication and also for their superfast speed.
Around 1978, Intel released 8086, the first 16-bit microprocessor. With 16-bit word size, it was possible to represent signed numbers in the range of −32,768 to +32,767, which is quite a decent range for performing arithmetic calculations. As such, this processor became very popular not only for control applications, but also for number crunching operations. Speeds of those processors were four times better than the 2nd generation processors. Not to be outdone, Motorola came out with 68000, their 16-bit processor. Zilog released Z-8000, again a 16-bit processor. These are the most popular 16-bit processors.
In the early 80s, Intel released the 32-bit processor, the Intel 80386, by using HCMOS fabrication. With 32-bit word size, it was possible to represent signed numbers in the range ±2×109, which is quite a large range for performing arithmetic calculations. If floating point notation is used, it can represent much larger numbers. As such, this processor became very popular as the CPU in computers for number crunching operations. At this time, Motorola came out with 68020, their 32-bit processor. Intel released 80486, which was basically an 80386 processor and 80387 numeric co-processor on a single chip. Motorola released 68030. In the early 90s, Intel released 80586 by the name Pentium processor. It is extremely fast in performing arithmetic calculations and executing instructions. The Pentium 4 released in 2000 has 42 Million transistors worked with a clock frequency of 1.5 GHz and is rated for 1500 MIPS (Million instructions per second).
From 1995 to until now this generation has been bringing out high-performance and high-speed processors that make use of 64-bit processors. The present-day computers based on microprocessors are already faster than the mini computers and sometimes the main frame computers of yesteryear, and they are available at a small fraction of the cost of such main frame computers.