SCHOOL OF ENGINEERING, ARCHITECTURE, AND FINE ARTS

COMPUTER FUNDAMENTALS AND PROGRAMMING

(LECTURE NOTES)HISTORY OF COMPUTERS

Note:

Historical records will tell us that man has invented three types of devices to assist him in calculating and processing data. These devices could be classified into:

1. Manual-mechanical is a simple mechanism powered by hand.

Ex. Abacus and slide rule

2. Electromechanical is usually powered by electric motor and uses switches and relays.

Ex. Household appliances, desk calculators and punched card data processing equipment.

3. Electronic has as its principal components circuit boards, transistors or silicon chips.

Ex. Modern digital computer First Computing Devices

1. ABACUS

- The first Manual Processing Device

- developed in China in 12th century

- consists of beads and wires

- Popular to be simple and effective

2. NAPIERS BONE

- invented by John Napier

a Scottish Mathematician

the father of logarithm

- consists of eleven rods with marked on each side

- Quotients and products can be obtained even at large

- made out of bone and ivory

3. OUGHTREDS SLIDE RULE

- the right was given by the English Mathematician named William Oughtred

- capable of doing quick multiplication and division

4. PASCALS CALCULATOR

- invented by Blaise Pascal who is considered as one of the modern scientist during his time

- can add and subtract number up to 8 digits with an automatic carry

5. LEIBNIZ CALCULATOR

- developed by Gottfried Leibniz

- Similar to the concept of a pascaline, however it can perform other arithmetic functions/ operations like division and multiplication.

6. BABBAGE ANALYTICAL ENGINE

- Developed by the acclaimed father of the modern computer Charles Babbage

- designed to use two cards

Operations Cards- to indicate the specific functions to be perform

Variable Cards to specify the actual data

7. HOLLERITHS PUNCHED CARD MACHINE developed by Herman Hollerith

Making use of 3x5 inches cards

Early Electronic Devices

1. Mark 1 (1st general purpose Digital Computer)

2. ENIAC (Electronic Numerical Integrator and Calculator)

3. EDVAC (Electronic Discrete Variable Automatic Computer)

4. UNIVAC( 1st Commercially produced digital Computer)

Five Generations1. FIRST GENERATION OF COMPUTERS (1939-1954) vacuum tube

Expensive and bulky.

machine language for computing and could solve just one problem at a time

Multi tasking is not supported

John V. Atanasoff designed the first digital electronic computer.

Atanasoff and Clifford Berry demonstrate in November the ABC prototype

Konrad Zuse in Germany developed in secret the Z3.

In Britain, the Colossus was designed in secret at Bletchley Park to decode German messages.

-Howard Aiken developed the Harvard Mark I mechanical computer for the Navy

-John W. Mauchly and J. Presper Eckert built ENIAC at U of PA for the U.S. Army

-Mauchly and Eckert start Electronic Control Co., received grant from National Bureau of Standards to build a ENIAC-type computer with magnetic tape input/output, renamed UNIVAC in 1947 but run out of money, formed in Dec. 1947 the new company Eckert-Mauchly Computer Corporation (EMCC).

2. SECOND GENERATION OF COMPUTERS (1954 -1959)

transistor

IBM introduced the 702 business computer

IBM International Business Machine

Small business computer machine were sold.

General Electric Corporation delivered its Electronic Recording Machine Accounting

3. THIRD GENERATION OF COMPUTERS (1959 -1971) Integrated Circuit (IC)

-The development of the integrated circuit was the hallmark of the third generation of computers

-Transistors were placed on silicon chips, called semiconductors, which drastically increased the speed and efficiency of computers.

-users interacted with third generation computers through keyboards and monitors and interfaced with an operating system, which allowed the device to run many different applications at one time with a central program.

Computers for the first time became accessible to a mass audience because they were smaller and cheaper than their predecessors.

4. FOURTH GENERATION OF COMPUTERS (1971-1991) microprocessor

The microprocessor brought the fourth generation of computers, as thousands of integrated circuits were built onto a single silicon chip.

IBM introduced its first computer for the home user

Apple introduced the Macintosh

small computers became more powerful

development of the Internet

GUIs (graphical user interface, the mouse and handheld devices.

central processing unit and memory to input/output controls - on a single chip.

5. FIFTH GENERATION OF COMPUTERS (Present and Beyond)

Artificial Intelligence

Still in development, though there are some applications, such as voice recognition, that are being used today

The use of parallel processing and superconductors is helping to make artificial intelligence a reality

The goal of fifth-generation computing is to develop devices that respond to natural language input and are capable of learning and self-organization.

DEFINITION OF COMPUTER

- is an electronic device that can execute instructions or commands to accept data (input) and processes it to produce a useful information (output).CHARACTERISTICS OF COMPUTERS

-All computers have certain common characteristics irrespective of their type and size. Computers are not just adding machines; they are capable of doing complex activities and operations. They can be programmed to do complex, tedious and monotonous tasks. Computers are what they are because of the following characteristics

1. WORD LENGTH

2. SPEED

3. STORAGE

4. ACCURACY

5. VERSATILITY

6. AUTOMATION

7. DILIGENCENote:

** A binary digit is called bit.** A group of 8 bits is called byte.** The number of bits that a computer can process at a time in parallel is called its word length.COMPUTER CAPABILITIES

1. Ability to Perform Certain Logic Operations

2. Ability to Provide New Time Dimensions

3. Ability to Store and Retrieve Information

4. Ability to Control Error

5. Ability to Check Itself

COMPUTER LIMITATIONS

1. Dependence on Prepared Instructions

2. Inability to Derive Meanings from Objects

3. Inability to Generate Information

4. It cannot Correct Wrong Instructions

WHY COMPUTER SOMETIMES FAILS

1. Input Errors

2. Errors in Instructing a Computer

3. The Communication Gap

4. Improper Controls

5. Lack of Standards

6. Lack of Adequate Manufacturer Support

APPLICATIONS OF COMPUTER

In business, computers have become very crucial that we cant even think how we will be able to survive without them. Businesses use computers for a variety of purposes ranging from decision making to electronic commerce.

Scientists and researchers use computers to develop theories, to collect and test data, to simulate test environments, and to exchange information electronically with colleagues around the world. Researchers can access databases in distant locations from their desktop.

In medicine today, computers are used for everything from diagnosing illnesses to monitoring patients during surgery and controlling permanent prostheses.

Computers have found their way in museums and libraries and they are rapidly becoming as essential to the classrooms way to classrooms and everyone from school children to research students use computers to work for their own intellectual benefit. You will find computers in classrooms, museums and libraries and they are rapidly becoming as essential to the learning process as are books, paper and pens.

Although drafting tables and T-squares are still around, their days may be numbered. An engineer or architect designing a product can be far more productive with a computer than with pencil and paper. In addition to product design, computers are playing an ever increasing role in manufacturing. Computers are used for everything from production

ELEMENTS OF COMPUTER1.Hardware

2.Software

3.Data & Information

4.Peopleware

5.Communication

I. HARDWARE refers to the equipment and machinery in a computer system or the physical component of a computer system.

CLASSIFICATIONS OF HARDWARE

1. INPUT DEVICES2. OUTPUT DEVICES

3. PROCESSORS

4. SECONDARY STORAGE5. COMMUNICATION DEVICES

A.INPUT DEVICES

- are devices that translate data into a form the computer can process.

Note:

INPUT- Everything we enter/tell the is input

TYPES OF INPUT

1. DATA is the raw facts given to the computer.

2. PROGRAMS are the sets of instructions that direct the computer.

3. COMMANDS are special codes or key words that the user inputs to perform a task, like RUN ACCOUNTS. These can be selected from a menu of commands like OPEN on the File menu. They may also be chosen by clicking on a command button.

4. USER RESPONSE is the users answer to the computers question , such as choosing OK, YES, or NO or by typing in text, for example the name of a file.

THREE TYPES OF INPUT DEVICES:

1. KEYBOARD contains all the typewriter keys and a number of specialized keys; this is a device that converts letters, numbers or any character into machine-readable form.

Examples: Traditional keyboards and specialty keyboards

Note:

A. The keys on computer keyboards are often classified as follows:

ALPHANUMERIC KEYS letters and numbers

PUNCTUATION KEYS comma, period, semicolon, and so on.

SPECIAL KEYS function keys, control keys, arrow keys, Caps Lock key, and so on.

B. There is no standard computer keyboard, although many manufacturers imitate the keyboards of PCs. There are actually three different PC keyboards :

ORIGINAL PC KEYBOARD with 84 keys.

AT KEYBOARD also with 84 keys. ENHANCHED KEYBOARD with 101 keys.

2. POINTING DEVICES are devices which control the position of the cursor or pointer on the screen.

Examples:

1. MOUSE is a small device that a computer user pushes across a desk surface in order to pint to a place on a display screen and to select one or more actions to take from that position. The mouse first became a widely used computer tool when apple computer made it of a standard part of the apple Macintosh.

Advantages: moves cursor around the screen faster than using keystroke.

Disadvantages: requires moving hand from keyboard to mouse and back.

2. TRACKBALL a stationary pointing device that contains a movable ball rotated with the fingers or palm. From one to three keys are located in various positions depending on the unit.

Advantage: Does not need as much desk space as a mouse.

Disadvantage: Requires fine control of the ball with just one finger or thumb.

3. POINTING STICK a pointing device that looks like a pencil eraser between the G, H and B keys. It is moved with the forefinger, while the thumb is used to press related keys located in front of the space bar.4. TOUCHPAD - a stationary pointing device that provides a small, flat surface that you slide your finger over using the same movements as you would a mouse. You can tap on the pads surface as an alternate to pressing one of the touchpad keys.

5. JOYSTICK a device consisting of a hand held stick that pivots about one end and transmits its angle in two dimensions to a computer. Joysticks are often used to control games, and usually have one or more push buttons whose state can also be read by the computer.

Advantage: a joystick gives a more natural-feeling control for motion in games, especially those where you are flying a plane or spaceship.

Disadvantage: better ones require an additional peripheral card for best performance.

6. LIGHT PEN a small, photosensitive device connected to a computer and moved by hand over an output display in order to manipulate information in the computer.

7. TOUCH SCREEN a display screen that is sensitive to the touch of a finger or stylus. Touch screens are very resistant to harsh environments where keyboards migh eventually fail. They are used with custom applications and on-screen buttons large enough to be pressed with the finger.

Advantage: It is natural to do reach out and touch something.

Disadvantage: It is tiring if many choices must be made. It takes a lot of screen space for each choice since fingers are bigger than cursors.

**Note:

RESISTIVE SCREENS There are two primary technologies used for touch screens, and both use a clear glass panel overlaid on the CRT or LCD screen. The resistive method is completely pressure sensitive. It uses a plastic layer on top of a metallic- coated by spacers. When pressed, it shunts the current in the glass panel, and the X-Y coordinates pick up the location on the screen.

CAPACITIVE SCREENS The capacitive method uses a metallic coated glass panel, but without the plastic overlay. It senses the change in current from the electricity in your finger or form a stylus wired to the computer that emits a charge.

8. PEN INPUT a computer that allows the user to input and retrieve data by writing with a stylus directly on a display screen.

Advantage: can use handwriting instead of typing.

Disadvantage: Must train device to recognize the ones you create.

3. SOURCE DATA ENTRY DEVICES are devices which create machine-readable data on magnetic media or paper or feed it directly into the computers processor.

Examples:

Scanning devices imaging systems, barcode readers, mark- and character-recognition devices.

1. Audio-input devices, Web cameras and video input and photographic input (digital cameras).Voice-recognition

2. Voice-recognition systems, sensors, radio-frequency identification devices, and human-biology input devices.

Note: HUMAN BIOLOGY INPUT DEVICES

BIOMETRIC SYSTEMS are security devices that identify a person through a fingerprint, voice, retinal, etc.

B. OUTPUT DEVICES

- are devices that translate information processed by the computer into a form that humans can understand.

- are devices that can convert machine readable information, obtained as the result of processing, into people readable form.

TWO PRINCIPAL KINDS OF OUTPUT

1. HARDCOPY refers to the printed output/printouts.

2. SOFTCOPY refers to the data that is shown on a display screen or is in audio or voice form.

KINDS OF OUTPUT DEVICES:

1. DISPLAY SCREEN

TYPES OF DISPLAY SCREEN

1. Interactive WhiteboardsThis technology requires three pieces of equipment: a computer (or laptop), a projector and a touch-sensitive whiteboard. The computer is connected to the projector and whiteboard, and the projector displays the computer screen image onto the board. The computer can then be controlled from the board. As you point at active elements on the board using your finger or an appropriate electronic 'pen', the action is transmitted to the computer as happens when using, for example, a mouse. Electronic pens (often described as e-pens) are usually attached by a cord to the board. More advanced boards offer cordless e-pens (infrared signal). The use of a pen together with appropriate software allows the user to directly mimic the two-button 'mouse' used on any modern computer system. Those boards that allow a finger to be used usually cannot entirely mimic the mouse operation although the software supplied is becoming increasingly sophisticated.

Types of interactive whiteboardInteractive whiteboards generally follow one of three design characteristics which carry a price premium:

The lowest cost is the infrared add-on (one size fits all) to an existing whiteboard which basically allows the board to become an electronic copyboard.

At a higher cost is the dual-membrane resistive board which can be operated with a pen or a finger/fingertip.

The highest cost comes with a solid state impact-resistant whiteboard, which can only be operated with an electronic pen or a more expensive variant, offering control via a cordless infrared pen and/or A5/A6 pads. The latter can offer extreme flexibility of use and trial schools report well on their use as part of a complete ICT teaching environment.

Whiteboards have many potential advantages and they can:

allow staff and/or students to move around a screen without the use of a computer because the screen itself is sensitive

offer the same features as a traditional whiteboard such as writing directly on the board, circling things, highlighting or labelling elements on the screen and erasing errors

offer an on-screen keyboard that floats over the software allowing you to enter text or data into almost any application

enable editing on screen and recording any/all changes or additions

encourage often technophobic tutors to deliver naturally using technology from the front of the room

enhance presentation content by easily integrating video/animation, graphics/text and audio

allow learners to absorb information better and participate in classroom discussions by freeing them from copious note-taking

save valuable preparation time

act as an electronic flip chart (up to 99 pages), with all notes and diagrams saved as an HTML file for later use across the college's intranet or virtual learning environment, allowing an archive to be easily maintained and displayed

allow notes to be stored and made available to students who missed the presentation/lecture

be used to communicate effectively with other locations using leading desktop conferencing applications such as Microsoft NetMeeting or Intel Proshare.

(Not all interactive whiteboards offer all the above features)2. Mimio

Mimio? consists of a folding 28" bar (14" x 7" x 2" when closed) that weighs under two pounds, four colour-coded dry-erase marker sheaths, and a pressure-sensitive eraser. The bar holds position-sensing optics and connects by cables to the serial (or Universal Serial Bus (USB)) and mouse ports of a PC. The marker sheaths are wired for ultrasonic and infrared transmission. When you write, Mimio? detects and records your pen strokes as images you can save for printing or perusal. You use the eraser to make corrections or to wipe out blocks of text.

Set-up is remarkably straightforward. The teal-coloured bar attaches by suction cups to the left side of a 3" x 4" whiteboard. In some initial (pre-production) tests, there were issues with suction cups giving way unexpectedly and pen-holders sometimes needing a lot of pressure to activate the board. Additionally changing the angle at which you hold the pen will slightly alter how a line appears on screen. Batteries are included and will require inserting into pens and eraser.

The manufacturers claim that Mimio? supports boards as large as 4" x 8" and it can be used with video conferencing software, including Microsoft's NetMeeting, to share whiteboard notes remotely across the Internet.

Connected to a projector and laptop, the laptop screen can be recreated on a vast scale on the whiteboard. The mouse pen makes the whiteboard interactive. The price of the Mimio ? means it is a useful competitor with the interactive whiteboard.

mimioMouseWhen projecting a presentation onto an ordinary whiteboard, mimioMouse is a cordless mouse that you can use to point and click, open and close windows or scroll through the slides.

The mimioMouse annotation mode, allows you to write notes onto the projected screen. This tool allows you to add notes to a text document, illustrate changes to a flow chart, highlight key points on a PowerPoint slide, or mark up a technical diagram. When you save or print the screen, your handwritten notes are included as they appear on the projected image.

As an added benefit, you can also pick up a mimio stylus to write on the actual whiteboard, and save those notes as well. Everything on the whiteboard is controlled from the front of the room.

3. eBeamThe eBeam? is a small compact right angle shaped device that is 5" X 5" and under 6 ounces (150 grammes). The device connects to your PC via USB. It can be placed in any corner of the white board. It comes with 4 coloured pen jackets and electronic board rubber, and has an accuracy of picking up lines/movements of 1mm (manufacturers statement). You can use the device in three modes:

Capturing writing/drawing on a whiteboard

Turning any whiteboard into an interactive whiteboard allowing you to run and use applications from the board.

Annotation of projected images from your PC. For example drawing around key points on a webpage or key icons in an application and capturing the image for use later in a variety of formats.

The set-up is simplicity itself. The equipment is USB so can be plugged and unplugged without restarting the PC. The accuracy of picking up writing on the board is excellent and issues such as the angle one holds a pen are not a problem with an eBeam?. The product on initial testing has proved to be very robust.

The ability to export the images when used as a whiteboard capture device or annotation of PC output in a variety of forms (JPEG, BMP or straight into PowerPoint show) or series of webpages complete with viewer that allows them to be viewed across the web, makes this new arrival in the display screen technologies sector in the UK worth a look.

4. Large Screen MonitorsIn smaller classrooms, with a small group of learners, large screen monitors can be used to display a particular concept to the learners. However, this is not as feasible when dealing with larger classes.

Large screen monitors do offer the following benefits:

Screen dimensions range from 29" to 38" (measured on the diagonal)

Both video and data input can be displayed

Light conditions in the room do not affect the screen, as it can be adjusted

Screen normally comes packaged with the necessary leads

One drawback is that this type of screen is not easily portable unless trolley mounted.

5. Plasma DisplaysPlasma displays are a relatively new technology and therefore can be expensive. However, the prices are falling, and plasma displays do provide a viable alternative to a large screen television. Plasma screens are large, flat monitors (4" to 6" in thickness) that accept both data and video signals. They also provide large screen images around 33" to 50" in size.

They have the advantages of:

being bright in any light conditions

being thin and thus fitting into a limited space

offering wide-angle viewing with no distortion of image

being either free-standing or wall mounted: (although mobile, free-standing models can be heavy)

6. ProjectorsA projector connects to the computer and projects the image directly onto a screen. Prices vary depending on the resolution, brightness and weight of the equipment. Consideration needs to be given to the size of the room and the lighting in the room.

Curtains or blinds could also improve the image. The demand for projectors is increasing in most colleges as they have the advantage of:

projecting large enough for a very large audience to see, for example in a classroom, a learning centre or in an IT suite

SVGA (Super Video Graphics Array) (800 x 600) being acceptable under normal circumstances

accepting video as well as data input in most cases

XGA (Extended Graphics Array) projectors are now more common and offer a resolution of 1024 x 768.

7. Television Screens

This is the simplest option for getting started and has the advantage of being relatively inexpensive using existing resources. A scan converter is used to link up a television to a computer providing a larger image for students to view. However, detailed material can be difficult to see on screen, as the resolution is low.

Types of Computer Monitors

A computer monitor, technically termed as a visual display unit, can be plainly described as an electronic device that transmits information from the computer onto a screen, thereby acting as an interface and connecting the viewer with the computer. At present, computer monitors are available in a variety of shapes, designs and colors. However, based on the technology used in the making of computer monitors, they can be broadly categorized into two types. These include CRT (cathode ray tube) and LCD (Liquid Crystal Technology).

1. CRT (Cathode Ray Tube) Monitors: These monitors employ the CRT technology used most commonly in the manufacturing of television screens. In this, a stream of intense high energy electrons is used to form images on a fluorescent screen. A cathode ray tube is a basically a vacuum tube containing an electron gun at one end and a fluorescent screen at another end. From this electron gun, a strong beam of electrons is generated by a process called thermionic emission. These electrons are made to travel through a narrow path within the tube with high speed using various electro-magnetic devices and finally strike the phosphor points present on the fluorescent screen, thus creating an image. There are several advantages of using CRT monitors.

These monitors are highly reliable, efficient and are capable of generating a resolution up to 2048 x 1536 pixels, thereby providing a clear picture quality. Also, CRT monitors that are now available are capable of producing thousands of different colors.

Secondly, CRT monitors are affordable and cost effective.

Unlike conventional CRT monitors, modern technological advancements have resulted in the development of flat screen CRT monitors that reduce the glare and are good for your eyes.

However, the only concern with buying CRT monitors is that they are heavy and can occupy a great deal of work space. Also, these devices get heated up very easily.

LCD (Liquid Crystal Display) Monitors: Liquid crystal display, also known as liquid crystal diode, is one of the most advanced technologies available at present. Typically, an LCD monitor consists of a layer of color or monochrome pixels arranged schematically between a couple of transparent electrodes and two polarizing filters. Optical effect is achieved by polarizing the light in varied amounts and making it pass through the liquid crystal layer. At present, there are two different types of LCD technology available. These include the active matrix or TFT, and a passive matrix technology. Among these, TFT technology is much secure, reliable and generates better picture quality. On the other hand, passive matrix has a slow response time and is slowly becoming outdated.

In the recent times, LCD monitors are becoming increasing popular with consumers. Some major advantages of using a LCD monitor include:

These monitors are compact, light in weight and do not consume much desk space.

Secondly, these monitors do not consume much electricity and can even be operated by using batteries.

Also, the images transmitted by these monitors do not get geometrically distorted and have little flicker.

However, LCD monitors do have certain disadvantages. Most importantly, these monitors are very much expensive. Secondly, image quality is not constant when viewed from different angles. Also, the resolution of an LCD monitor is always constant. Any alterations can result in a reduced performance.

2. PRINTERS are devices that print characters, symbols and perhaps graphics on paper or another hardcopy medium.TWO TYPES OF PRINTERS

1. IMPACT PRINTERS form letters, number and other images out of dots by striking an inked ribbon against a paper (there is a physical contact between the printing mechanism and the paper)

E.G. dot-matrix printer

2. NON-IMPACT PRINTERS form characters and images without making a direct contact between the mechanism and the paper.

E.g. Laser printers, inkjet printer, DeskJet printer,

3. MULTIFUNCTION DEVICES combine several capabilities, such as printing, scanning, copying, faxing in one device

4. SOUND PROCESSORS AND SPEAKERS allow us to play digital music and other sounds.

Note:

1. Processing is the thinking that the computer does the calculations, comparisons, and decisions.2. Processor is a shortcut for microprocessor. A microprocessor incorporates most or all functions of a central processing unit (CPU) on a single integrated circuit (IC)CENTRAL PROCESSING UNIT (CPU) - controls and manipulates data to produce information. Acts as the brain and the heart of a computer system

TYPES OF PROCESSOR

1. DUAL-CORE PROCESSOR - its dual core technology rewrites the rules of computing delivering optimized power efficient computing breakthrough dual-core performance with amazingly low power consumption. With its two execution cores, the Intel Core Duo processor is optimized for multi-threaded applications and multitasking. You can simultaneously run multiple demanding applications such as graphics-intensive games or serious number crunching programs. 2. MULTI-CORE PROCESSOR Multi-core-chip with two or more separate processors. This type of processor increases the speed of computer.

PARTS OF THE CPU

1. CONTROL UNIT - controls and directs the movement of electronic signals between main memory and ALU or between the main memory and input/output devices.

2. ARITHMETIC LOGIC UNIT (ALU) is a digital circuit that performs mathematical and logical operations. The ALU is a fundamental building block of the central processing unit (CPU) of a computer, and even the simplest microprocessors contain one for purposes such as maintaining timers.3. MAIN MEMORY (PRIMARY STORAGE/ RAM/ VOLATILE STORAGE) - serves as the working area/space of a computer. Is like an electronic scratch pad inside the computer. When you launch a program it is loaded into and run from the memory. As new data is entered into the computer, it is also stored in memory but only temporarily. Note:

**Storage- refers to the media and methods used to keep information available for later use. Some things will be needed right away while other wont be needed for extended periods of time, so different methods are appropriate for different uses.

Note:

TWO TYPES OF STORAGE DEVICE

1. Primary storage is Main Memory. This keeps track of what is currently being processed. It is volatile.(Power off erases all data)2. Secondary Storage is called Auxiliary Storage. This is what is not currently being processed. This is the stuff filed away, but ready to be pulled out when needed. It is non-volatile. (Power off does not erase.)

CHARACTERISTICS OF MAIN MEMORY

The content is temporary

Capacity varies in different computers

The memory capacity is in terms of Kilobytes, megabytes, gigabytes and terabytes

The capacity determines the software that a computer can run

THREE TASKS OF THE MAIN MEMORY It holds data for processing

It holds programs for processing the data

It holds the processed data/information

CLASSIFICATION OF MEMORY

VOLATILE MEMORY when the computer is turned off, the contents will be lost.

NON- VOLATILE - doesnt lose the contents when the computer is turned off.

MEMORY SIZES

UNITABBREVIATIONSIZEEQUIVALENT

BitAn atom, the smallest unit of memory

Byte8 bitsA single letter, a number or a symbol

KilobyteK or KB1,024 bytesA one-page, double-spaced letter

MegabyteM or MB1, 048, 576 bytesA bestselling novel

GigabyteG or GB1, 073,741,824 bytesAn encyclopedia set

TerabyteT or TB1,099,511,627,776 bytesA bookstore

OTHER MEMORY SIZESQUANTITIES OF BYTES

Common PrefixBinary Prefix

Name SymbolDecimalBinaryNameSymbolBinary

PetabytePB10 r 152 r 50PebibytePiB2 r 50

ExabyteEB10 r 182 r 60ExbibyteEiB2 r 60

ZettabyteZT10 r 212 r 70ZebibyteZiB2 r 70

YottabyteYB10 r 242 r 80YobibyteYiB2 r 80

TYPES OF COMPUTER MEMORY

RAM (Random Access Memory) a type of memory chip that is byte addressable and provides direct access to any location on the chip. The contents of any byte can be read or written without regard to the bytes before or after it.

DRAM (Dynamic Random Access Memory) has an extremely short data lifetime-typically about four milliseconds. This is true even when power is applied constantly.

SRAM (Static Random Access Memory) - retains its contents as long as electrical power is applied to the chip. If the power is turned off or lost temporarily, its contents will be lost forever. HYBRID can be read and written as desired, like Ram, but maintain their contents without electrical power, just like ROM. Two of the hybrid devices, EEPROM and flash, are descendants of ROM devices. These are typically use to store code. The third hybrid, NVRAM, is a modified version of SRAM. NVRAM usually holds persistent data.

NVRAM (Non-Volatile Random Access Memory) non-volatility is also a characteristic of the ROM and Hybrid memories. An NVRAM is usually just an SRAM with a battery back-up. When the power is turned off, the NVRAM draws just enough power from the battery to retain data.

FLASH MEMORY combines the best features of the memory devices described thus far. Flash memory devices are high density, low cost, non-volatile, fast (to read, but not to write) and electrically reprogrammable.

EEPROM (Electrically-Erasable-and-Programmable Read Only Memory) internally, they are similar to EPROMs, but the erase operation is accomplished electrically, rather than by exposure to ultraviolet light. Any byte within an EEPROM may be erased and rewritten.

ROM (Read Only Memory) memory that allows fast access to permanently stored data but prevents addition to or modification of the data.

MASKED ROM - the very first ROMs were hardwired devices that contained pre-programmed set of data or instructions. The contents of the ROM had to be specified before chip production, so the actual data could be used to arrange the transistors inside the chip. Hardwired memories are still used; though they are now called masked ROMs you distinguish them from other types of ROM. The primary advantage of a masked ROM is its low production cost. Unfortunately, the cost is low only when large quantities of the same ROM are required.

PROM (Programmable ROM)- the process of writing your data to the PROM involves a special piece of equipment called a device programmer, in which it writes data to the device one word at a time by applying an electrical charge to the input pins of the chip. Once a PROM has been programmed in this way, its contents can never be changed. If the code or data stored in the PROM must be changed, the current device must be discarded. As a result, PROMs are also known as one time programmable (OTP) devices. EPROM (Erasable-and-Programmable ROM) this is programmed in exactly as the same as a PROM. However, EPROMs can be erased and reprogrammed repeatedly. To erase an EPROM, you simply expose the device to a strong source of ultraviolet light. (A window in the top of the device allows the light to reach the silicon ). By doing this, you essentially reset the entire chip to its initial-unprogrammed-state. Though more expensive than PROMs, their ability to be reprogrammed makes EPROMs an essential part of the software development and testing process.

SYSTEM UNIT refers to the box/cabinet that contains the electrical components:

a. POWER SUPPLY that converts AC current to DC to run the computer

b. RAM or Random Access Memory Temporary storage whose contents can be opened and modified

c. ROM or read-only memory cannot be written on or erased. Contents can be read but not altered. It stores basic Instructions to run the computer system.

d. MOTHERBOARD: Main circuit board of the computer system

e. CPU Chips or the microprocessor

f. Expansion slots, disk drives, hard disks

TYPES OF AUXILIARY STORAGE1. Magnetic disk. This method uses magnetism to store the data on a magnetic surface .

2. Optical Disk. Is an electronic data storage medium that can be written to and read using low-powered laser beam. TYPES OF MAGNETIC DISKS

1. Floppy Disk/Diskette. It is a soft magnetic disk. It is called floppy because it flops if you wave it(at least, the 5 -inch variety does). Unlike most hard disks, floppy disks (often called floppies or diskettes )are portable , because you can remove them from a disk drive. Disk drives for floppy disks are called floppy drives.Speed: very slow

Capacity: very small 1.44 Megabytes(MB)

Coat: very cheap2. Hard Disk. The primary computer storage medium, which is made of one or more aluminium or glass platters, coated with a ferromagnetic material. Most hard disk are fixed disks which have platters that reside permanently in the drive. Almost all computers have an internal hard disk, and external units can be plugged in for additional storage or backup.

The other type of hard disk is a removable disk encased in a cartridge, allowing data to be ejected from the drive for external storage or transfer to another party. Before high speed Internet connections were common, removable SyQuest, Jaz, and Zip cartridges were routinely shipped via the post office.Speed: very fast. Most hard disk has an average access speed of between 8 to 15 milliseconds (ms)

Capacity: Enormous. Many hard disks have more than200 Gigabytes (GB) of storage.

THEREE MAJOR CATEGORIES: PATA, SATA AND SCSIMost hard disks are Parallel ATA (PATA), Serial ATA (SATA) or SCSI. SCSI drives have traditionally have been found on servers and high performance workstations and were the first drives used in fault tolerant RAID systems. Today ATA drives are widely used in RAID arrays. 3. Zip Disk. A 3.5 removable disk drive from Iomega. Zip disks come in 100 MB, 250 MB and 750 MB varieties, with the latter introduced in 2002, using USB and FireWire interfaces. The 250 MB drives, introduced in 1998, also read and write 100MB disks. The 750 MB drives read all, but only write 250 MB and 750 MB disks.

Zip disks are a floppy-like technology that uses design concepts from hard disks and Iomegas earlier Bernouili disks. The drive is bundled with software that can catalog the disks and lock the files for security. When Zip disks were introduced in 1995, they became popular very quickly.Speed: Significantly slower than most hard disks.

Capacity: 100 to 750 Megabytes (MB)

4. Flash memory Cards/ USB (Universal Serial Bus) FLASH DRIVESFlash memory is non-volatile computer memory that can be electrically erased and reprogrammed. It is a technology that is primarily used in memory cards and USB flash drives (thumb drives, handy drive, memory stick , flash stick , jump drive , Cap N Go ) for general storage and transfer of data between computers and other digital products . Trek was the first company to sell a USB flash drive (Thumb Drive) in early 2000.TYPES OF OPTICAL DISK

CD-ROM (Compact Disc Read Only Memory)CD-ROMS can store lots of information: a single CD-ROM can hold more than 600 Megabytes (MB) of data more than encyclopedia set.

Speed: Much slower than a hard disk , but still faster than a floppy

Capacity: About 650 Megabytes (MB)CD TYPEDESCRIPTION

CD-ROMThe original, standard CD. You can only read information from a CD-ROM. You cant add new information in it.

CD-RYou can permanently store information on a CD-R (Compact Disc Recordable). The information you write or burn on a CD R is permanent and cant be changed or erased.

CD-RWUnlike a CD-R discs, a CD-RW (Compact Disc Rewritable)disc can be written many times .You can also modify and erase information on a CD-RW disc.

DVD(Digital Versatile Disc) A DVD looks just like CD-ROM, but it can store more than 4 Gigabytes (GB) of information - as much as seven CDs

Speed: Faster than a CD-Rom but not as fast as a Hard Disk.

Capacity: Usually about 4 Gigabytes (GB) although future DVD disc are rumoured to hod up to 17 Gigabytes (GB)

DVD FORMATDESCRIPTION

DVD ROMThe original, standard DVD. You can only read information from a DVD. You cant add new information in it.

DVD-RYou can permanently store information in it. The information you write or burn to a DVD-R is permanent and cant be changed

DVD-RWYou can rewrite up to 1,000 times. You can also modify and erase information in it.

DVD+RYou can permanently store information on DVD+R disc. The information you write or burn in it is permanent and cant be erased or changed.

DVD+RWYou can rewrite up to 1,000 times. You can also modify and erase information in it.

DVD-RAMDVD-RAM is rewritable DVD format that can be re-written many times. DVD RAM disc are beginning to look like an orphan format , since they wont work in most DVD players.

COMMUNICATION DEVICES

these devices allow computers to communicate with other machines.

EXAMPLES:

1. MODEM - is an electronic device that allows computers to communicate with each other over the telephone lines.

2. CABLES - are wires, telephone line (fiber optics, coaxial cables, twisted pairs, etc)

* Peripheral Devices are external devices connected to your computer. E.g. mouse, keyboard, speaker, printer, etc

II. SOFTWARE consists of the step-by-step instructions that tell the computer how to perform a task

A. APPLLICATION SOFTWARE is software that has been developed to solve a particular problem, to perform useful work on specific tasks, or to provide entertainment.TYPES OF APPLICATION SOFTWARE1.Entertainment Software the serious matter of videogames.

Ex. Pac-man, super Mario, mortal combat, etc

2.Educational and Reference Software help students be more receptive to learning.

Ex. Mathblaster(problem-solving game), CD-ROMs with encyclopaedias, maps, etc.

3.Business and Specialized software include programs for desktop publishing, personal finance, project management, computer-aided design, drawing and painting and hypertext.

3. Productivity Software consists of programs found in most offices and probably on all campuses, on PCs and other computer systems.4. Personal Software

Ex. Cookbooks, Medical, Home decoration, Gardening, Home repair etcVARIOUS FORMS OF APPLICATIONS SOFTWARE USED AS PRODUCTIVITY TOOLS

WORD PROCESSING SOFTWARE allows you to use computers to format, create, edit, print and store text material.

SPREADSHEETS Allows the users to create tables and financial schedules by entering data into rows and columns arranged as a grid on a display screen.

DATABASE SOFTWARE is a computer-based collection of interrelated files. It is a program that controls the structure of a database.

PRESENTATION GRAPHICS SOFTWARE allows people to create graphical representation of data to present to other people.

COMMUNICATIONS SOFTWARE manages the transmission of data between computers

INTEGRATED SOFTWARE combine the features of several features of applications programs into one software package

GROUPWARE is a software used on a network that serves a group of users working together on the same project.Note:

**Commercial software - Copyrighted. If you dont pay for it, you can be prosecuted.( Also proprietary software or packaged software, is software that is offered for sale).

**Public domain software Not copyrighted. You can copy it for free without fear of prosecution. (Is not copyrighted and thus may be duplicated by anyone at will). **Shareware - Copyrighted. Available free, but you should pay to continue using it. (Is copyrighted software that is distributed free of charge but requires users to make a monetary contribution to continue using it.)**Freeware- Copyrighted. Available free. (Is copyrighted that is distributed free of charge) **Rentalware- Copyrighted. Lease for fee.

**Pirated software is software obtained illegally.

**Copyright - is the exclusive legal right that prohibits copying of intellectual property without the permission of copyright holder.

**Software license you sign a contract in which you agree not to make copies of the software to give away or for resale.

** Version a major upgrade in a software product, traditionally indicated by numbers such as 1.0, 2.0 ,3.0.**Release an add or addition, is a minor upgrade.COMMON FEATURES OF SOFTWARE User Interface the user controllable display screen that allows you to communicate , or interact, with the computer. Pointer usually appears as an arrow, although it changes shape depending on the application.

Note:

THE GUI: THE COMPUTERS DASHBOARD

In the beginning computers had command-driven interfaces, which required you to type in strange looking instructions such as copy a:\filenmae c:\ to copy a file from a floppy disk to hard disk). In the next version, they had menu driven interfaces, in which you could use the arrow keys on your keyboard or mouse to choose a command from a menu, or list of activities. Today the computers dashboard is usually a graphical user interface (GUI), which allows you to use a mouse or keystrokes to select icons (little symbols) and commands from menus (lists of activities)B. System software enables the application software to interact with the computer and helps the computer manage its internal and external resources.

THREE BASIC COMPONENTS OF SYSTEM SOFTWARE1. Operating System (also called software platform) is the principal component of system software in any computing system.

consists of the master system of programs that manage the basic operations of the computer.

Functions:

a. BOOTING

refers to the process of loading an operating system into a computers main memory from diskette or hard disk.

Uses diagnostic routines to test system for equipment failure

Stores BIOS(basic input-output system) programs to main memory

this loading is accomplished by a program (called bootstrap loader or boot routine) that is stored permanently in the computers electronic circuitry.

Example: A:\> or C:\> - System Prompt indicates the operating system has been loaded into main memory and asks you to enter a command.

Note:

** When you power up a computer by turning on the power on switch, it is called a cold boot.** If your computer is already on and you start it, this is called a warm boot or a warm start (by simultaneously pressing Ctrl+Alt+Del keys or pressing the Reset button on your computer)

b. USER INTERFACE the user controllable display screen that allows you to communicate or interact, with your computer.3 Types:

Command-driven requires you to enter command by typing in codes or words

Ex. DIR

Menu-driven allows you to chooses command from a menu.

Ex. Menu bar, Pulldown menu

Graphical User uses images to represent options and permits liberal use of the mouse. The function represented by the icon can be activated by pressing (clicking) buttons on the mouse

Ex. ICONS are small pictorial figures that represent tasks, functions or programs

d. CPU MANAGEMENTthis activity is performed by the supervisor, or kernel, the central component of the operating system. The supervisor, which manages the CPU, resides in main memory while the computer is on and directs other programs to perform tasks to support application programs.

It also manages memory it keeps track of the locations within main memory where the programs and data are stored.

It can swap portions of data and programs between main memory and secondary storage.

Ex. Partitioning they divide memory into separate areas called partitions

NOTE:

**Partitioning - in partitioning, the OS divides memory into separate areas called partitions, each of which can hold a program or data.

**Foreground/background some computer systems divide memory into foreground and background areas. Foreground programs have higher priority and background programs have lower priority.

**Queues programs that are to be executed wait on disk in queues. A queue is a temporary holding place for programs or data. The disk area where the programs or documents wait is called buffer.e. FILE MANAGEMENT

Note

**A file is a named collection of related information. A file can be a program such as word processing program.

OS allows you to find for files of data and programs located in many places on the hard disk and other secondary-storage devices.

Allows you to copy, or duplicate, files and programs from disk to another.

Allows you to back-up or make a duplicate copy of, the contents of a disk.

Allows you to erase, or remove from a disk any files or programs.

Allows you to rename, or give new filenames, to the files on a disk.

f. TASK MANGEMENTA computer is required to perform many different tasks at once. In Word Processing for example it accepts input data, stores the data on a disk, and prints out a document seemingly simultaneously.Among the ways operating systems manage tasks in order to run more efficiently are: * Multi-tasking is the execution of two or more programs by one user concurrently- not simultaneously on the same computer with one central processor. The processor directs the programs to take turns accomplishing small tasks or events within the programs. Ex. Calculation, searching of records, etc. (concurrently, one after the other)

* Multiprogramming is the execution of two or more programs on a multi-user operating system. (at the same time on a uniprocessor) (the operating system executes part of one program, then part of another, and so on. To the user it appears that all programs are executing at the same time.)

* Time-sharing is a single computers processing of the tasks of several users at different stations in round-robin fashion. It is used when several users are linked by a communications network to a single computer. It is being done through TIME SLICING computers operate so quickly that it is possible for them to alternately apportion slices of time (fractions of a second) to various tasks. The computer spends a fixed amount of time with each program before going to the next one.

* Multi-processing is processing done by two or more computers or processors inked together to perform work simultaneously (the use of two or more central processing units (CPUs) within a single computer system. The term also refers to the ability of a system to support more than one processor and/or the ability to allocate tasks between them)g. FORMATTING (or initializing) Is the process of preparing the disk so that it can store data or programs.h. SECURITY MANAGEMENT Operating systems now allow users to control access to their computers, this is especially important when several people use one computer and when on networks, in which various people use one system.OTHER SYSTEM SOFTWARE

1. DEVICE DRIVERS are specialized software programs that allow input and output devices to communicate with the rest of the computer system. 2. UTILITY PROGRAMS also known as SERVICE PROGRAMS, perform tasks related to the control and allocation of computer resources. They enhance existing functions provide services not supplied by other system software programs.

Among the tasks performed by utilities are the following: BACK UP UTILITY. Refers to process of making a duplicate copy of the information on your hard disk.

DATA RECOVERY UTILITY. Is used to restore data that has been physically damaged or corrupted. Data can be damaged by viruses, bad software, hardware failure, and power fluctuations.

VIRUS PROTECTION.

**Antivirus software is a utility program that scans hard disks , floppy disks , and memory to detect viruses. DATA COMPRESSION.

**Data Compression Utilities remove redundant elements, gaps, and unnecessary data from a computers storage space so that less space (fewer bits) is required to store or transmit data.

REMINDERS:

Never start your computer from an unknown floppy disk. Always make sure your floppy disk drive is empty before turning on or restart your computer.

Run virus scanning software on a new floppy disk before executing, installing, or copying files into your system.

If you download or install software from a network server (including the Internet), bulletin board, or online service, always run scanning software on the directory you place the new files in before executing them.

Create a start-up diskette containing the virus scan program. Make sure this floppy disk is write-protected so that it cannot become infected.

Scan files attached to e-mail before you open them.

If your internet connection is always on (for example, if you have a cable modem), purchase special software called firewall software to keep other Internet users out of your computer.

Do not open e-mail from unknown resources.

FIILE DEFRAGMENTATION

Note:

** Over time, as you delete old files from your hard disk and add new ones, something happens :the files become defragmented.

FRAGMENTATION is the scattering of portions of files about the disk in nonadjacent areas, thus greatly slowing access to the files.

DEFRAGMENTER UTILITY PROGRAM commonly called defragger will find all the scattered files on your hard disk and reorganize them as contiguous.OPERATING SYSTEMS AND ENVIRONMENTS

a. DOS (Disk Operating System) runs primarily on IBM and IBM-compatible microcomputer

Types:

* Microsofts MS-DOS

* IBMs PC-DOS

b. MACINTOSH OPERATING SYSTEM (Mac OS) it is easy to use. Its graphics capabilities make the Macintosh a popular choice for people working in commercial art, desktop publishing and engineering design.

c. WINDOWS for DOS is an operating environment made by Microsoft that lays a graphical user interface shell around the MS-DOS or PC-DOS operating system

d. OS/2 designed to run on many recent IBM and compatible microcomputer. It can receive a fax and run a video while at the same time recalculating a spreadsheet. It is also the first operating system created just for todays new workgroup environments.

e. WINDOWS 95 and later the successor to Windows 3.1 for DOS, is a true operating system for IBM-style personal computers rather than just an operating environment

f. WINDOWS NT Windows for New Technology. It is intended to support large networks of computers.

g. UNIX is an operating system for multiple users and has built-in networking capability, the ability to run multiple tasks at one time, and version that can run on all kinds of computers.

h. NETWARE has become the most popular operating system for coordinating microcomputer-based local area networks (LANs) throughout a company or campus.

2.External Utility Programs are special programs that provide specific useful services not performed less well by other systems software programs

I) SOME SPECIFIC UTILITY TASKS

a. SCREEN SAVER is a utility that supposedly prevents a monitors display screen from being etched by an unchanging image(burn-in)

b. DATA RECOVERY used to undelete a file or information that has been accidentally deleted

c. BACKUP duplicate copy of the information on the hard disk

d. VIRUS PROTECTION

Virus consists of hidden programming instructions that are buried within an applications or systems program.

e. Antivirus software is a utility program that scans hard disks, diskettes and microcomputers memory to detect viruses.

f. FILE DEFRAGMENTATION

Fragmentation - is the scattering of portions of files about the disk in non-adjacent areas, thus greatly slowing access to the files.

g. DATA COMPRESSION removes redundant elements, gaps, and unnecessary data from a computers storage space so less space is required to store or transmit data.

3. Language Translators is a software that translate program written by a programmer in a language such as BASIC into machine language, which computer can understand.

3 types:

* Assemblers (assembler program) is a program that translates the assembly-language program into machine language.

* Compilers(Execute later) language translator that converts the entire program of a high-level language into machine language before the computer executes the program.

Ex. Of high-level languages using COMPILERS Cobol, Fortran and Pascal

* Interpreters (Execute immediately)- an interpreter is a language translator that converts each high-level language statement into machine language and executes it immediately, statement by statement.

Ex. Of High level language using an INTERPRETER - Basic

GENERATION OF PROGRAMMING LANGUAGES:

1ST generation: MACHINE LANGUAGE basic language of the computer, representing data as 1s and 0s which corresponds to the on and off electrical states of the computer.

2ND generation: ASSEMBLY LANGUAGE is a low-level language that allows programmer to use abbreviations or easily remembered words instead of numbers. USES ASSEMBLER as a language translator.

Ex. MP = multiply

STO = store

3RD generation: HIGH-LEVEL LANGUAGES is an English-like language, such as COBOL used for business applications. Allow users to write in familiar notation, rather than numbers or abbreviations. USES COMPILERS or INTERPRETERS depending on the Language.

4TH generation: VERY-HIGH-LEVEL LANGUAGES much more user-oriented and allow programmers to develop programs with fewer commands compared with 3RD generation languages. These are non-procedural because programmers do not need to write as many lines of code as they do with procedural languages. It consists of REPORT GENERATORS, QUERY LANGUAGES, APPLICATION GENERATORS, and INTERACTIVE DBMS

5TH generation: NATURAL LANGUAGES 2types: ORDINARY HUMAN LANGUAGE English, Spanish. PROGRAMMING LANGUAGES uses human language to give people a more natural connection with computers.

ARTIFICIAL INTELLIGENCE is a group of related technologies that attempt to develop machines to emulate human-like qualities, such as learning, reasoning, communicating, seeing and hearing.

I) Ethics and Intellectual Property Rights: When can you copy?

Intellectual Property consists of the products of the human mind. Such property can be protected by copyright, the exclusive legal right that prohibits copying it without the permission of the copyright holder.

Software piracy, network piracy, and plagiarism violate copyright laws.

I) COPYRIGHT

is the exclusive legal right that prohibits copying of intellectual property without the permission of the copyright holder.

Copyright law protects books, articles, pamphlets, music, art drawings, movies and computer software.

COPYRIGHT-RELATED MATTERS:

SOFTWARE AND NETWORK PIRACY

SOFTWARE PIRACY is the unauthorized copying of copyrighted software.

NETWORK PIRACY is using electronic networks for the unauthorized distribution of copyrighted materials in digitized form.

PLAGIARISM

is the expropriation of another writers text, findings or interpretations and presenting it as ones own.

III. INFORMATION AND DATA Data consists of raw facts and figures that are processed into information

Information is summarized data or otherwise manipulated data that is useful for decision making

In electronic form, data can be organized into bits, bytes, fields, records, files and databases. That is data is arranged into the following increasingly sophisticated levels.

BITS. Computers deal with on and off electrical states, which are represented as 0s and 1s. Each 0 or 1 is called a bit (short for binary digit).

BYTES or CHARACTERS

A group of 8 bits is called a byte

BYTE holds the equivalent of a character

CHARACTER is a single letter, number, or special symbol (such as punctuation mark or dollar sign). Example of characters are A, 1, ?

BITS and BYTES are what the computer hardware deals with. People using software, deals with characters, fields, records, files and databases.

FIELDS is a nit of data consisting of one or more characters

Ex. Name, address, SSS number

RECORDS is a collection of related fields

Ex. Name and address and SSS number

FILES is a collection of related records.

Ex. Information of everyone in a class, including all names, addresses and SSS numbers

DATABASES is a collection of interrelated files

Ex. On a College Campus that includes names, address of students from many college classes and from many departments.

Units of Measurement for Capacity

Computers represent data in terms of 0s and 1s called bits. Bits are grouped as 8 bits called bytes to represent numerals, letters, and special characters. Storage capacity is represented by kilobytes, megabytes, gigabytes and terabytes.

* Kilobyte. Abbreviated K or KB. This is equivalent to approximately 1000 bytes or characters

* Megabyte. Abbreviated M or MB. This is about 1 million bytes.

* Gigabyte. Abbreviated G or GB. This is about 1 billion bytes.

* Terabyte. Abbreviated T or TB. This is about 1 trillion bytes.

IV. PEOPLE consists of the users or personnel involved in data processing operations They are the most important part of and beneficiaries of the computer- communications system.

Types of people using IT:

1. Professionals. These are people who have had formal education in the technical aspects of using a computer-and-communications system.

2. End-users. These are those without much technical knowledge of information technology, who use computers computers for entertainment, education or work-related tasks

COMPUTER JOB DESCRIPTION:

1. SYSTEMS PROGRAMMER is responsible to

a. Equip analysis and selection

b. Develop, acquire and effectively utilize programming languages.

c. Select and maintain OS and time-sharing facilities

d. Develop technical specifications for future computers, systems and applications

e. Establish programming standards.

2. SYSTEM ANALYST analyze computer-based applications or operations, specific functions include:

a. Determine proposed applications

b. Develop general methodologies to be employed

c. Determining proposed computerized applications to be effectively integrated into the operational structure of the organization.

d. Preparing program specifications and form layouts

3. APPLICATION PROGRAMMER develops computer programs. His functions include detailed specifications of the program, coding, debugging, testing and documentation.

4. OPERATIONS PERSONNEL

a. Data Preparation Personnel paper work both into and out the computer such as data entry, Librarian records the status of production programs and data files.

b. Scheduling Personnel concerned with the running of production programs.

c. Equipment Operators operate the computer equipment.

-Starting the computer and loading the systems program

-Mounting tapes and disk packs

-Responding to informational requests from the OS

-Recognizing when the computer is malfunctioning and calling the repair personnel.

I. PROCEDURES are descriptions of how things are done, steps for accomplishing a result. In other computer systems, these are spelled out in manuals. Manuals, called documentation, contain instructions, rules, or guidelines to follow when using hardware or software.

I. COMMUNICATIONS is the electronic transfer of data from one place to another

CYBERSPACE is the whole world of wired or wireless communication

INFORMATION TECHNOLOGY-the technology that merges computers and high speed communication technology

The data being communicated may consist of voice, sound, text, video, graphics or all of these together.

Two Modes of Communications

* Tree- branch model : a centralized information provider sends out messages through many channels to thousands of consumers. This is the model of most mass media, such as radio and TV broadcasting.* Switch-network mode : people on the system are not only consumers of information but also possible providers. This is a model of the telephone system and also most computer networks.The significance of the two types is the Tree- branch allows only few-to-many communications. The switch-network allows many-to-many communications.

The Practical Uses of Communications and Connectivity

1. Telephone Related Communication Services. Services available through telephone connections, whether the wired kind, or the wireless cellular phone type, including the following:

a. Fax messages can be sent by dedicated fax machine or by fax modem

* Dedicated fax machine specialized device that does nothing except send and receive copies of documents over transmission lines to and from other fax machines.

* Fax modem installed as a circuit board inside a computers system cabinet

-a modem with fax capability

b. Voice mails digitizes incoming voice messages and stores them in the recipients voice mailbox in digitized form

c. E-mails links computers by wired or wireless connections and allow users, through their keyboards, to post messages and to read responses on their display screens

2. Teleconferencing. Is a meeting among people remote from one another who are linked by a communication device, such as telephone, television or computer.

Types:

a. Audio teleconferencing. Often called a conference call, is a meeting among people in different geographical locations using the telephone.

b. Video teleconferencing. Usually called video conferencing. It is provided by video cameras and monitors that allow people at different locations to see and hear one another.

c. Computer teleconferencing. A keyboard conference among several users at microcomputers or terminals linked through a computer network. Often the conference is held on the bulletin board system.

d. Document conferencing. Meeting participants not only see and hear one another but also work on text and graphic projects at the same time.

e. Personal videoconferencing. Combines video conferencing with computer and document conferencing.

3. Shared Resources, Workgroup Computing and EDI

a. Shared Resources. Companies discovered that connectivity allowed people to share equipment that would be affordable for one microcomputer. More important, employees found, networks allowed them to share files as well. Networking using common software also allowed users to buy equipment from different manufacturers.

b. Workgroup computing. Enables team of coworkers to use networks of microcomputer to share information and cooperate on projects.

c. Electronic data interchange. Is the direct electronic exchange between organizations computer system of standard business documents, such as purchase orders, invoices and shipping documents.

4. Portable Works: Telecommuting, Mobile Workplaces and Virtual Offices.

a. Telecommuting and telework centers. Working at home with telecommunications between offices and home is called telecommuting. Telework includes not only those who work at least part time from home but also those who work at satellite offices.

b. The mobile workplace. Many people are still on the road, but often they are expected to take their work with them. truckers may now be required to carry laptops with which they keep in touch via satellite with headquarters. More and more field service representatives, sales people, and roving executives find that to stay competitive they must bring office technology with them.

c. The virtual office. The term virtual office borrows from virtual reality (artificial reality that projects the user into computer generated three-dimensional space).. It is an often non permanent and mobile office to rum with computer and communications technology.

5. On line Information Services. It provides access to all kinds of databases and electronic meeting places to subscribers equipped with telephone-linked microcomputers.

* Research

* E-Mail

* Games

* Travel services

* Shopping

6. Electronic Bulleting Board Systems. It is a centralized information source and message-switching system for a particular computer-linked interest group. There seem to be no limits to the topics of conferences or electronic talk forums on bulleting boards.

two types:

a. Large commercial BBSs. All major on line services, such as America online, Compuserve, and Progidy, operate bulletin board. However, BBSs are only one of the several services offered by commercial services. And, of course, you are charged by the organization for using the particular feature.

b. Small BBSs. may be free or for-profit , but they are generally run by individuals, often out of their homes.

HOW DATA IS TRANSMITTED:

A

B

C

D

E

* Data originates from the Transmitting Device or Sending Device(A)

* Data in Digital form will be converted to Analog signal using modem(B)so that it can be transmitted over the communication channel(C)

* Data in analog signal is now transmitted over the communication channel(C)

* Transmitted signal in analog form will be converted back to digital signal so that it can be manipulated by the receiving computer.

I) TWO TYPES OF TRANSMISSION

1. ANALOG TRANSMISSION-transmitting analog signal

ANALOG SIGNAL is a continuous electrical signal in the form of wave

Characteristics of Analog Signal:

a. Frequency- refers to the number of times a wave is repeated during a time interval

- measured in herts(hz)

b. Amplitude- refers to the loudness/softness of a signal(volume of a signal)

- refers to the height of a wave

2. DIGITAL TRANSMISSION-transmitting digital signals(0/1)

DIGITAL SIGNAL discrete bursts/distinct pulses(0 or 1/ high or low)

CONNECTIVITY refers to state of being able to connect devices by communication technology to other devices and sources of information

COMMUNICATION CHANNELS- the path over which data in the form of signals travels in a communications system

Wired Communication: Twisted Pair, Coaxial Cable, Fiber Optics

a. Twisted pair consists of two or more strands of insulated copper wire, twisted around each other in pairs.

b. Coaxial cable, commonly called coax, consists of insulated copper wire wrapped in a solid or braided metal shield, then in external cover.

c. Fiber optic cable consists of thousands or thin strands of glass that transmit not electricity but rather pulsating beams of light.

Wireless Communication: Microwave Systems/Satellite Systems

a. Microwave systems transmit voice and data through the atmosphere as super-high frequency waves.

b. Satellites Systems. Communications satellites are microwave relay stations in orbit around the earth.

c. One-way communications:

* Global Positioning System (GPS). This consists of a series of 24 earth-orbiting satellites that continuously transmit timed radio signals that can be used to identify earth locations. A GPS receiver handheld or mounted in a vehicle, plane, or boat can pick up transmissions from any four satellites, interpret the information from each, and calculate to within a few hundred feet or less the receivers longitude, latitude or altitude.

* Pagers. These, commonly known as beepers are simple radio receivers that receive data (but not voice messages) sent from a special radio transmitter.

d. Two-way communications

* Analog Cellular. These cellular phones are primarily designed for communicating by voice through a system of cells.

* Packet Radio. Packet-radio-based communications use a nationwide system of radio towers that send data to handheld computers.

* CDPD. Short for Cellular Digital Packet Data. This places messages in packets, or digital electronic envelopes, and sends them through underused radio channels or between pauses in cellular phone conversations

I) COMPUTER/COMMUNICATIONS NETWORK

NETWORK is a system of interconnected computers, telephones or other communication devices that can communicate with each other and share data and application

I) TYPES OF NETWORKS

A. WIDE AREA NETWORK (WAN): A network that covers a wide geographical area such as a state or country.

Example: telephone system-long- distance or local

B. METROPOLITAN AREA NETWORK(MAN):a network that covers a geographical area the size of a city

Example: Cell Phone systems

C. LOCAL NETWORKS: a privately owned communication network that serves users in a confined geographical area

* in-house network within an office, building, group of buildings close together

TWO TYPES OF LOCAL NETWORK

A. LOCAL AREA NETWORK(LAN)-Local network consisting of a communication link, network OS, computers, servers and shared resources

B. PRIVATE BRANCH EXCHANGE(PBX)- a private or leased telephone switching system that connects the telephone extension in house

I) ADVANTAGES OF A NETWORK

1. sharing of peripheral devices

2. sharing programs or files

3. better communication

4. better security of information

5. access to databases

I) NETWORK TOPOLOGIES

TOPOLOGY is the physical layout or shape of a network

1. STAR TOPOLOGY-all computers and other communication devices re connected to a central server where communication must pass

2. RING TOPOLOGY-all computers and other devices are connected in a continuous loop

3. BUS TOPOLOGY-all devices are connected in a single or common channel

Factors Affecting Data Transmission:

1. Transmission Rate: Higher Frequency, Wider Bandwidth, More data

* Frequency. The amount of data that can be transmitted on a channel depends on the wave frequency the cycles of waves per second. The more cycles per second, the more data that can be sent through that channel

* Bandwidth. This is the difference between the highest and the lowest frequencies that is, the range of frequencies. The greater the bandwidth of a channel, the more frequencies it has and hence the more data that can be sent through that channel. The rate of speed of data through the channel is expressed in bits per second.

2. Line Configurations: Point-to-Point & Multipoint

* Point-to-point. A point-to-point line directly connects the sending and receiving devices, such as a terminal with a central computer. This is appropriate for private line whose sole purpose is to keep data secure while transmitting it from one device to another.

* Multipoint. A multipoint line is a single line that interconnects several communications devices to one computer.

3. Serial & Parallel Transmission

* Serial data transmission. In here, bits are transmitted sequentially, one after the other.

* Parallel data transmission. In here, bits are transmitted through separate lines simultaneously.

4. Direction of Transmission Flow: Simplex, Half Duplex, & Full Duplex

* Simplex Transmission. Data can travel only in one direction.

* Half-duplex Transmission. Data travels in both directions but only in one direction at a time.

* Full-duplex Transmission. Data is transmitted back and forth at the same time.

5. Transmission Mode: Asynchronous versus Synchronous

* Asynchronous Transmission. Data is sent one byte (or character) at a time. Each string of bits making up the byte is bracketed, or marked off, with special control bits.

* Synchronous Transmission. This sends data in blocks. Start and stop bit patterns, called sync bytes are transmitted at the beginning and end of the blocks.

6. Packet Switching. A packet is a fixed-length block of data for transmission. Packet switching a technique for dividing electronic messages into packets for transmission over a network to their destination through the most expedient route. The benefit of packet switching is that it can handle high-volume traffic in a network. It also allows more users to share a network, thereby offering cost savings.

7. Multiplexing. This is the transmission of multiple signals over a single communications channel.

8. Protocols. A protocol or communications protocol is a set of conventions governing the exchange of data between hardware and / or software components in a communications network. This is built into the hardware or software you are using.

n Taylor

DEPARTMENT OF COMPUTER ENGINEERING 5