Generation of Computer

    Classification of computer in different time-frame based on their technological development is called generation of computer. 
A generation of computer refers to a distinct phase in the development of computer technology that is characterize by a specific set of technological advancements, innovations and changes in design.

Till now, there are 5 generation of computer. They are:- 

First Generation Computer

• Timeline : 1946 – 1959
• Technology : Vacuum Tubes
• Input Device : Punch card, teletypewriter, keypunch
• Output Device : Punch card, paper tape, teletype printer
• Programming Language : Machine Level Language
• Speed Measure : Milliseconds
• Memory : Vacuum tubes-based memory, magnetic drums and tapes
• Operating system: No OS. Operations are performed by human
• Applications : Scientific and military application
• Characteristics : - Large in size
                             - Consumed more power
                             - Slow in speed
                             - More noisy
                             - Generate lots of heats
                             - Expensive in cost
• Examples : UNIVAC-I, Mark-I, EDSAC, EDVAC, ENIAC, IBM-650, IBM-702, IBM-205, etc

Second Generation Computer

• Timeline : 1959 – 1965
• Technology : Transistors
• Input Devices : Punch cards, teletypewriter, paper tape reader
• Output Devices : Magnetic tapes, teletype printer, initial CRT display
• Programming Language : Assembly Language
• Speed measure : Microseconds
• Memory : Magnetic core & drum memory, magnetictapes and disks
• Operating System : Simple Batch Operating System, OS/360, TOPS-10
• Applications : Business applications, scientific calculation
• Characteristics : - Smaller then 1st than gen computer
                             - Consume less power
                             - Improve in speed
                             - Generate less heat
                             - Costly
                             - More Reliable
• Examples : IBM 1401, IBM 1400, IBM 7000, IBM 7090, IBM 7094, ICL 2950/10, NCR-300, UNIVAC 1107, CDC 1604, CDC 3600, etc.

Third Generation Computer

• Timeline : 1965 – 1971
• Technology : Integrated Circuit (IC)
• Input Devices : Keyboard, Mouse
• Output Devices : Monitor, printer, plotter
• Programming Language : High Level Language(C, PASCAL, BASIC, COBOL, FORTAN)
• Speed measure : Nanoseconds
• Memory : Large magnetic core, magnetictapes and disks
• Operating System : Multiprocessing OS (UNIX, MULTICS, VMS)
• Applications : Business, scientific, personal calculation and engineering task
• Characteristics : - Decrease in size than previous generation 
                             - Improve speed and more reliable
                             - Cheaper
                             - More efficient and accurate
• Examples : IBM 360, IBM 370, PDP-8, PDP-11, UNIVAC 1108, UNIVAC 9000, STAR, TDC-316, CDC 6600, etc.

Fourth Generation Computer

• Timeline : 1971 – Till date
• Technology : LSI, VLSI, Microprocessor
• Input Devices : Keyboard, Mouse, Scanner, touchpad, digitizer, OMR, MICR, etc.
• Output Devices : Monitor, printer, speaker, plotter, projector, etc. 
• Programming Language : 4GL, High level language (Python, C#, Java, JavaScript, Rust, etc)
• Speed measure : Picoseconds
• Main Memory : RAM, ROM, SRAM, DRAM, etc
• Secondary Memory: HDD, SSD, CD, DVD, Flash memory, memory card, etc
• Operating System : GUI Based OS (Windows, IOS), MS-DOS, etc
• Applications : Personal computing, school, office, hospital, scientific research, banking, etc.
• Other features: Multimedia, Networking, distributed computing are introduced
• Examples :IBM PC (Dell, acer, HP, Lenovo), STAR 1000, Mac PC, Super Computer, Mobile, Tablet, etc.

Fifth Generation Computer

• Timeline : Present and beyond
• Technology : AI based chips, ULSI ICs
• Input Devices : Voice recognition, touch pen, hand gesturing, touch screen, etc
• Output Devices : Printer, 3D printer, hologram, projector, etc
• Programming Language : Natural Language (English, Nepali, Hindi)
• Speed measure : Femtoseconds
• It is also called under-developing generation of computer.
• Knowledge Information Processing System(KIPS), Parallel process, Quantam Processing will be used.
• Nanotechnology will be completely used.
• Computer will have IQ and logical power decision making capabilities like human.
• More powerful, cheaper, reliable, easy to use and portable.
• Remarkable improvement of speed, accuracy and efficiency.
• Rapid software development will possible.
• Less power consuming, Heating and noisy
• Examples : Deep Blue, IBM Watson, Google Assistant, Siri, Param, Sophia robot, other robotic system, etc

Technology used in difference generation of computer

1. Vacuum Tube/Fleming Valve
   - Inventor: John Ambrose Fleming
   - Year: 1904
   - Used: Basic component of CPU and memory, amplifucation and switching in early computer
2. Transistor
   - Inventor: John Bardeen, William Shockley and Walter Brattain
   - Year: 1947
   - Used: Replaced Vacuum Tubes, Fundamental to modern electronic devices, Circuit switching and signal amplification
3. Integrated Chip(IC)
   - Inventor: Jack St.Clair Kilby and Robert Noyce
   - Year: 1961
   - Used:Compact arrangement of transistors on a single chips, miniturization of circuits
4. Microprocessor
   - Inventor: Intel Company (Federico Faggin, Ted Hoff and Stan Mazor)
   - Year: 1971
   - Used: CPU on a single chip
   - First Microprocessor - Intel 4004(4 bits)