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Fundamentals of Computer: For undergraduate courses in commerce and managementAuthor: ITL Education Solutions Limited
ISBN:9788131733349
Available through:Parama Publishers & Distributors Ltd.
Momtaz Plaza (3rd Floor) House 7 Road 4 Dhanmondi Dhaka 1205 Bangladesh
T +88 02 9611971-5 9661141 9662282
Introduction
A computer is
• an electronic machine
• devised for performing calculations and controlling operations that can be expressed either in logical or numerical terms.
Development of civilization
• Fingers and pebbles for computing
• computing needs also grew
• Harnessing the power of computers
Characteristics Of Computers
• Speed
• Millions of instructions per second. 1 MHz (Megahertz) is one million instructions per second.
• Accuracy
• Capable of doing only what it is instructed to do
• faulty instructions~ GIGO (Garbage In Garbage Out)
• Diligence
• No tiredness and/or lack of concentration
• Reliability
• Some predetermined standard for operation without any failure
• Hardware level- built-in diagnostic capabilities
Characteristics Of Computers …
Storage Capability
• Store large amounts of data
• Recall almost instantaneously
The main memory~ relatively small
• The secondary storage devices• such as magnetic tape or disks.
•brought into the main memory for processing
Versatility
• Perform multiple tasks simultaneously
• Play music and print a document and ...
Characteristics Of Computers …
Resource Sharing
• Not isolated machines!
• Computers today have the capability to connect with each other
• Apart from device sharing, data and information can also be shared among groups of computers, thus creating a large information and knowledge base.
Development Of Computers
Chronology
• Fingers
• Pebbles
• Sand Tables
• Abacus
• Napier Bones
• Slide Rule
• Pascaline
• Stepped Reckoner
• Punch Card System
• Difference Engine
• Analytical Engine
• Hollerith's Tabulator
Other related dev.
• vacuum tube
• differential analyzer
Growth in commerce and other human activities
Some Early Computers
• MARK-I Computer 1937+
• IBM Sponsored
• ABC Computer 1939
• Binary arithmetic, regenerative memory, logic
• Colossus 1944
• 1800 vacuum tubes, programmable
• ENIAC 1946
• 18000 vacuum tubes, 160 KW, 30 tons
• EDVAC, EDSAC, UNIVAC
• Different technology
Generations Of Computers
• First Generation (1940–56): Vacuum Tubes
• Memory- magnetic drums (data, programs)
• Input- punched cards and paper tape
• Output was displayed in the form of printouts
• Large size, expensive to operate, unreliable, lack of standard in programming
• ENIAC, EDVAC, and UNIVAC.
• Second Generation (1956–63): Transistors
• More portable. Still required air conditioning
• Much smaller than vacuum tubes
• Assembly language- used mnemonics
• Computational time of these computers was reduced to microseconds from milliseconds
Generations Of Computers …
• Third Generation (1964–early 1970s): IC
• Integrated circuit (IC) technology
• Faster- microseconds to nanoseconds
• More portable and reliable
• Cheaper- less power and generated less heat, maintenance cost was quite low
• Commercial production- easier and cheaper
• Fourth Generation (Early 1970+): Microprocessors
• Size? AC Required? Portability? Reliability?
• Cost?- production? maintenance?
• Interconnection of computers- resource sharing
• Internet
Generations Of Computers …
• Fifth Generation (Present And Beyond): Artificial Intelligence
• Mega Chips- Super Large Scale Integrated (SLSI) •Millions of electronic components on a single chip
•approximate the memory capacity of the human mind
• Parallel Processing•multiple central processing units
• Artificial Intelligence (AI)• simulate and reproduce human behavior
• including thinking, speaking and reasoning
•AI comprises a group of related technologies
• expert systems (ES), natural language processing (NLP), speech recognition, vision recognition, and robotics.
Classification Of Computers- Purpose
• General-purpose Computers
• Perform a range of tasks, Store numerous programs
• Generally lack speed and efficiency
• Used in your schools and homes
• Specific-purpose Computers
• Designed to handle a specific problem or to perform a single specific task
• Instructions (specific task) built into the machine
• Circuits are redesigned for another type of task• Lacks versatility
• Fast and efficient
• Airline reservations, satellite tracking, air traffic control.
Data handling- Analog Computers
• Works on the principle of measuring• measurements obtained are translated into desired
data
• Electrical parameters, such as voltages, resistances or currents, to represent the data
• Does not deal directly with the numbers.• measure continuous physical magnitudes (such as
temperature, pressure, and voltage), which are analogous to the numbers under consideration.
• Petrol pump may have an analog computer that converts the flow of pumped petrol into two measurements – the quantity of petrol and the price for that quantity.
• They give approximate results
• Very fast in operation as all the calculations are done in ‘parallel mode
• The accuracy of analog computers is less
Data handling- Digital Computers
• Data represented in a digital form
• process data (including text, sound, graphics, and video) into a digital value (in 0s and 1s)
• Analog quantities must be converted into digital quantity before processing
• Output is digital
• The digital output has to be converted into analog quantity if required.
• Higher accuracy at a faster rate
• The desktop PC at your home is a classic example of digital computer.
Data handling- Hybrid Computers
• Measuring feature of an analog computer plus the counting feature of a digital computer
• Computational purposes- analog components
• Storage- digital memories
• Uses analog-to-digital and digital-to-analog converters
• Broadly used for scientific applications, various fields of engineering and in industrial control processes.
Functionality- Micro Computers
• Small, low cost digital computer
• Consists of a microprocessor, a storage unit, an input channel, and an output channel
• all of which may be on one chip inserted into one or several PC boards
• Requires a power supply and connecting cables, appropriate peripherals (keyboard, monitor, printer, disk drives, etc.), an operating system and other software programs can make a complete system
• Originally designed for individual users only
• Now powerful to support businesses functions
• Networked together- serve multiple user
Functionality- Micro Computers …
• Desktop Computer
• Most common micro computer
• Intended for stand-alone use by an individual.
• Typically consist of a system unit, a display monitor, a keyboard, internal hard disk storage, and other peripheral devices
• Laptop
• Portable computer- travelling, built in battery
• Also known as notebooks
• Smaller computers enclosing all the basic features of a normal desktop computer
• Expensive as compared to desktop computers
Functionality- Micro Computers …
• Hand-held Computers
• Also called Personal Digital Assistant (PDA)
• Also known as palmtop computers
• Stored in a pocket, used by the user is holding it
• Uses a pen or electronic stylus vs. keyboard
• Can be connected to printer or a disk drive to generate output or store data
• Limited memory and are less powerful
Functionality- Mini Computers
• Also called a mid-range computer
• Higher performance than micro computers- process and store less data than a mainframe • Often connected to a mainframe in order to perform
the auxiliary operations.
• Size~ of a two-drawer filing cabinet
• Designed to meet the computing needs for several people simultaneously in a small to medium size business environment. • Multi-user systems - capable of supporting from 4 to
about 200 simultaneous users
• Centralized storehouse for a cluster of workstations or as a network server.
• These are also used for real-time controls and engineering design work. High-performance workstations with graphics requirement.
Functionality- Mainframe Computers
• Mainframes are the second largest (in capability and size) of the computer family
• high-volume, processor-intensive computing
• Centralization- It consists of a high-end computer processor, with related peripheral devices, capable of supporting large volumes of data processing, high performance on-line transaction processing systems, and extensive data storage and retrieval.
• However, a mainframe can usually execute many programs simultaneously at a high speed, whereas super computers are designed for single processes.
Functionality- Super Computers
• Special purpose machines, which are specially designed to maximize the numbers of FLOPS (Floating Point Operation Per Second)
• More than one gigaflop/sec is considered a super computer
• Range of 400–10,000 MFLOPS
• For solving scientific and engineering problems
• Contains a number of CPUs that operate in parallel to make it faster.
• Super computers help in many applications such as information retrieval computer-aided design.
• Can resolve complex mathematical equations
The Computer System
Intelligent thinking
machine?
• Input Unit• Central
Processing Unit (CPU)
• Output Unit• Memory/
Storage Unit
Types Of Input Devices
• Keyboard
• Pointing Devices
• Mouse, Trackball, Joystick,touch-screen, digitizer pen
• Camera
• Scanners- different types
• OCR software (Optical Character Recognition)
• OMR software (Optical Mark Recognition)
• MICR (Mag. Ink Character Reader)
• Bar code reader- multiple types
Types Of Output Devices
• Hard copy Vs. Soft copy
• Printers-
• Dot matrix, daisy wheel, drum, ink-jet, laser
• Plotters- pen based (Slow, high res.)
• flat, drum
• Monitor
• Resolution, DPI, Refresh rate
• LCD and CRT and …
Types Of Memory
• Primary Memory
• RAM, ROM
• Secondary memory
• Floppy/USB
• Hard disk
• Magnetic tape
Applications Of Computer
ScienceEducationMedicine and Health CareEngineering/Architecture/ManufacturingEntertainmentCommunicationBusiness ApplicationPublishingBanking