Computer Generations

Key for Computer Generations Year Components used Memory Operating Speed Example Language Used 1st 1940-56 Vaccum tubes/thermonic valves Magnetic drum (10,000 -20,000 characters) Milli sec ENIAC EDVAC EDSAC Machine language 2nd 1956-63 Transistor Magnetic core and disk. (Up to 64,000 characters) Micro sec PDP-8 IBM1401 IBM7090 Assembly lang, Mnemonics 3rd 1964-early 1970’s Integrated circuits Semi-Conductor (Up to 4 million characters) Nano sec NCR 395 B6500 High level lang, BASIC,FORTAN,PASCAL 4th Early 1970-till date Micro processor 1-10 nano sec Apple II, Altair8800CRAY-1 4GL 5th Present & beyond Artificial Intelligence CMOS 1-100 nano sec -

First Generations 1940- 1956 These computers used vacuum tubes for circuitry and magnetic drums for memory. It is a metal cylinder coated with magnetic iron-oxide material on which data and programs can be stored. Input: punched cards and paper tape. Output was displayed on printouts. It is a binary coded language to perform operations and was able to solve only one problem at a time.

Advantages: Disadvantages: Vaccum tubes were the only electronic components available at that time. These computers were the fastest calculating device. Perform computations in milli seconds. Very big in size. No reliability Non portable. High heat production. High power consumption. High cost.

Second Generation 1956-1963 These computers used transistors, which were superior to vacuum tubes. It is a made up of semiconductor material like germanium and silicon. It usually had three leads and performed electrical functions as voltage, current or power amplification with low power requirements. It is a simple device; the physical size of computers was greatly reduced. Magnetic cores were used as primary memory and magnetic disks as secondary storage devices. Input: punched cards; Output: printout The major development includes the progress from machine language to assembly language. Assembly language used mnemonics for instructions rather than numbers. Ex: ADD, MULT High level languages COBOL, FORTRAN also came into existence.

Advantages: Disadvantages: Small in size. Better Reliability. Better Portability. Less heat generated. Better speed. Computational time in micro seconds. High cost. Frequent Maintenance required. Manual assembly of individual components.

Third Generation 1964- Early 1970’s These computers used an IC (integrated circuit), which consists of a single chip (usually silicon) with many components such as transistors and resistors fabricated on it. This development made computers smaller in size, reliable and efficient. Semi-conductor memory elements replaced the magnetic core memory and magnetic disk fully replaced the magnetic tapes as storage medium. Users interacted with third generation computers through keyboards and monitors and interfaced with operating system. Another concept developed during this period was the OS and high level languages. It allows the device to run many different applications at one time with a central program that monitored the memory.

Advantages: Disadvantages: Small in size. Better Reliability. Better Portability. Less heat generated. Less power consumption. Computational time in micro seconds. Need Air conditioning. Highly sophisticated technology required for the manufacture of IC chips.

Fourth Generation 1970’s to till date The development of microprocessor (circuit containing millions of transistors) integrated with storage, input and output unit produces a micro computer. A microprocessor is built onto a single piece of silicon known as chip which is about 0.5cm along one side and no more than 0.05cm thick. It leads to an era of LSI (large scale integration technology) VLSI (very large scale integration ) It became more powerful, compact, reliable and affordable. It uses Semiconductor memories, which resulted in faster random access main memories and secondary memories such as hard disks. It also saw the development of the GUIs (Graphical User Interface), mouse and handheld devices.

Advantages: Disadvantages: Much more small in size. Very cheap compared with previous generation computers. More reliability. Less power consumption. Large & Faster primary & secondary storage. Highly sophisticated Technology required for the manufacture of LSI chips.

Fifth Generation - Present Computers may operate at incredibly fast speed and perform with unbelievable accuracy. But they are unable to act or think on their own. When an Artificial Intelligent machine could be developed which will even be in a position to think & decide. Recent researchers are aimed at designing the logic for the thinking computers for building expert systems and knowledge based systems.

Advantages: The super computers fall under this generation. Portable PC’S also fall under this generation. Consumes less power. User friendly Supports wide OS environments. Supports newer and powerful applications. Having faster and large primary storage capacity.

Information is Power