Third Generation of Computers

3rd Generation of Computer wuth a comparison with 1st and 2nd Generation Computers

1. 1 st Generation Computer The first computer systems used vacuum tubes for circuitry and  magnetic drums  for  memory , and were often enormous, taking up entire rooms. These computers were very expensive to operate and in addition to using a great deal of electricity, the first computers generated a lot of heat, which was often the cause of malfunctions. First generation computers relied on  machine language , the lowest-level programming language understood by computers, to perform operations, and they could only solve one problem at a time. It would take operators days or even weeks to set-up a new problem. Input was based on punched cards and paper tape, and output was displayed on printouts. The UNIVAC and  ENIAC  computers are examples of first-generation computing devices. The UNIVAC was the first commercial computer delivered to a business client, the U.S. Census Bureau in 1951.

2. First Generation: Vacuum Tubes (1940-1956) An electronic device that controls the flow of electrons in a  vacuum . It is used as a switch, amplifier or display screen (CRT). Used as on/off switches,  vacuum tubes allowed the first  computers  to perform digital computations. A  vacuum tube  triode is a transconductance device; a voltage controls a current. Essentially, within a  vacuum  bulb, a cathode is heated (directly or indirectly) such that electrons are 'boiled' off (thermionic emission). The electrons flow from the plate through the battery to the cathode and a current is established.

3. Second Generation Computers Characteristics of Second Generation of Computers: Use of transistors. Magnetic memory and magnetic storage disks. High speed I/O devices. Invention and use of high level languages such as Fortran and Cobol. Reduced size. Solution to heat generation. Communication by using telephone line. Improvement of speed and reliability.

4. Second Generation: Transistors (1956-1963) The  transistor  was successfully demonstrated on December 23, 1947 at Bell Laboratories in Murray Hill, New Jersey. Bell Labs is the research arm of American Telephone and Telegraph (AT&T). The three individuals credited with the invention of the  transistor  were William Shockley, John Bardeen and Walter Brattain. A  transistor  is an electronic component that can be used as an amplifier, or as a switch. It is made of a semiconductor material.  Transistors  are found in most electronic devices. A  transistor  has three connectors or terminals. In the older bipolar  transistor  they are the collector, the emitter, and the base.

5. Third Generation Computers The  Computers  of  third generation  used Integrated Circuits (ICs) in place of transistors. A single IC has many transistors, resistors, and capacitors along with the associated circuitry. The IC was invented by Jack Kilby. This development made  computers  smaller in size, reliable, and efficient.

6. Characteristics of Third Generation computers: Integrated circuits instead of individual transistors Smaller, cheaper, more efficient and faster than second generation computers High-level programming languages Magnetic storage Semiconductor Memories Introduction of Microprogramming Parallel Processing Multiprocessing OS allowed the Machine to run many Applications

7. Integrated Circuit (IC) Jack Kilby of Texas Instruments made this first integrated circuit , in 1958. The idea occurred to a number of inventors at the same time, but the first to accomplish it were Jack Kilby of Texas Instruments and Robert Noyce of Fairchild Semiconductor Incorporated. An  integrated circuit , or  IC , is small chip that can function as an amplifier, oscillator, timer, microprocessor, or even computer memory. An  IC  is a small wafer, usually made of silicon, that can hold anywhere from hundreds to millions of transistors. Integrated circuits (ICs) are  self -contained circuits with many separate components such as transistors, diodes, resistors and capacitors etched into a tiny silicon chipsistors , resistors, and capacitors. 1958 1964

8. Microprocessors (1971) In 1971, the first Microprocessor   Intel 4004 was invented. Intel introduced the now-famous world's first single chip microprocessor ( ​the computer on a chip), the  Intel 4004 , invented by Intel engineers Federico Faggin , Ted Hoff, and Stanley Mazor . Technical specifications: Maximum  clock rate  is 740  kHz . 12-bit addresses 8-bit instructions 4-bit data  words Instruction execution time 1 or 2 machine cycles (10.8 or 21.6 µs), 46250 to 92500 instructions per second.

9. Types of Integration Scales Scale of Integration SSI (Small Scale Integration) MSI (Medium Scale Integration) LSI (Large Scale Integration) VLSI (Very Large Scale Integration) ULSI (Ultra Large Scale Integration) Number of Transistors 2 ≈ 64 64 ≈ 2,000 2,000 - 64,000 64,000 - 2,000,000 2,000,000 - No Limit

10. ICs with Different Integration Scales ULSI VLSI LSI MSI SSI