Basic Computer Fundamentals

Introduction A computer is an electronic machine, operating under the control of instructions stored in its own memory, that can accept data, manipulate the data according to specified rules, produce results, and store the results for future use. Computers process data to create information. Data is a collection of raw unprocessed facts, figures, and symbols. Information is data that is organized, meaningful, and useful. To process data into information, a computer uses hardware and software. Hardware is the electric, electronic, and mechanical equipment that makes up a computer.
Software is a series of instructions that tell the hardware how to perform tasks.
Characteristics of Computers

Automatic: Requires human intervention to start any task, solve the problem but once initiated, it continues the job until it’s completed.
Speed: in terms of microseconds (10 power -6), nanoseconds(10 power -9), and even picoseconds (10 power -12). A powerful computer is capable of performing several billions of simple arithmetic operations per second. Limited by hardware and software resources. Accuracy: garbage-in-garbage-out (GIGO).
E. g. Human input error, programmer logic error.
Diligence: Unlike human beings, a computer is free from monotony, tiredness, and lack of concentration.
Versatility: Can perform multiple tasks at the same time. Limited by hardware and software resources.
Power of Remembering: As long as the user desires, it can store any amount and type of information. Limited by hardware and software resources. No IQ: Cannot make decisions until instructed. Cannot learn on its own. No Feelings: No emotions, no taste, no knowledge.

Instructions are required.

Evolution of Computers Necessity is the mother of invention then who is the father? – Curiosity, Vision, Idea 1642: Pascal invented first mechanical adding the machine 1671: Baron Gottfried Wilhelm von Leibniz first calculator for multiplication 1880: Keyboards & Herman Hollerith used punch cards as input devices 19th century: Charles Babbage, father of the modern digital computer, Differential Engine, Analytical Engine.
The Mark I Computer (1937-44).
The Atanasoff-Berry Computer (1939-42).
The ENIAC (1943-46).
The EDVAC (1946-52 5. The EDSAC (1947-49). The UNIVAC I (1951).
Computer Generations Overview of the major developments and technologies during the five generations of computers which include both hardware and software that together make up a computer system.
First Generation (1942-1955): – Used vacuum tubes(glass), performed calculations in milliseconds -Memory electromagnetic relays, Data & Instructions using Punch Card, Assembly Language Programming Characteristics: Bulky in size, thousands of vacuum tubes, constant maintenance, costly, all circuits were man-made. g. ENIAC, EDVAC, EDSAC, UNIVAC 1, and IBM 701 1.
Second Generation (1955-1964): – Used transistor, Germanium semiconductor, magnetic disks and tapes, magnetic core memory – faster, small in size, low cost, consume less power – High-level programming language like FORTRAN, COBOL, ALGOL, SNOBOL.
 Third Generation (1964-1975): -Integrated Circuits(IC) consists of transistors, resistors, capacitors, SSI(Small Scale Integration), MSI – faster, performed one million instructions per second -low space, more reliable, less power consumption e. Minicomputers & Mainframe computers.
Fourth Generation (1975-1989): – personal computer, IC- LSI, VLSI – one million electronic components on a single chip. Semiconductor memories – less power, more fast, small in size – Magnetic tapes, floppy disks, LAN, WAN, GUI, MS-DOS, Windows, Macintosh.
Fifth Generation (1989-Present): – VLSI & ULSI(Ultra Large Scale Integration) – Microprocessor chips: 10 million electronic components Small, much faster, less power, portable, internet.
Block Diagram of Computer.
Input Unit: – Accept data & Instructions – Convert into digital form so that computer can accept and further processing can be done e. g. Mouse, Keyboard, Light Pen, Joystick, Scanner, Touch Screen
Storage Unit: The storage unit performs the following major functions: All data and instructions are stored here before and after processing. Intermediate results of processing are also stored here.
Primary Storage(Main Memory): – This memory is generally used to hold the program being currently executed in the computer, the data being received from the input unit, the intermediate and final results of the program. -Temporary in nature, i. e. volatile memory -fast and the cost is high than secondary storage -e. g. Random Access Memory(RAM).
Secondary Storage/External Memory(Secondary Memory): – Long term/ permanent storage of data. -slow and cost is low than primary memory -e. g. Floppy Disk(FDD), Hard disk drive(HDD), Compact Disk(CD), Digital Versatile/Video Disk, USB Drive, SDD.
Memory size: -Digital Computer uses the Binary System i. e. 0’s and 1’s – Each character or a number is represented by an 8-bit code. -1 bit = either 0 or 1 – 4 bits= 1 nibble & 8 bits= 1 byte.
Output Unit: – Any peripheral devices that converts the stored binary coded data into convenient external forms as texts, pictures, sound – e. g. Monitor, CD, Printer, Speaker, Headphones, plotter, projector 1. 4. 5 Arithmetic Logical Unit: All calculations(arithmetical +-x/ ), comparison(<,>,=) and decisions – Whenever.
Calculations are required, the control unit transfers the data from the storage unit to ALU once the computations are done, the results are transferred to the storage unit by the control unit, and then it is sent to the output unit for displaying results.
Control Unit: -It controls all other units in the computer -The control unit instructs the input unit, where to store the data after receiving it from the user, and how to output. It controls the flow of data and instructions:(fetching of instructions from main memory and subsequent execution of these instructions).
Central Processing Unit: The ALU and the CU of a computer system are jointly known as the central processing unit. You may call CPU as the brain of any computer system. – A PC may have CPU-IC such as Intel 8085, 8086, 8088, 80286, 80386, 80486, Celeron, Pentium, Pentium Pro, Pentium II, Pentium III, Pentium IV, Dual-Core, Core 2 Duo, Quad-Core, and AMD, etc.