CMP 101 Computer Essentials Part I

Computer Hardware

What is a computer?

Operates under the control of a set of instructions (program) that is stored internally within the computer's memory.

An electronic device that accepts data as input, manipulates (processes) that data to produce information (output) and store the results for future processing.

What is a computer? In general, the term “Computer” is

used to describe a collection of devices that work together as a system. Examples include:System UnitKeyboardMouseMonitorPrinter

What does a computer do?

The Information Processing Cycle: Input (Data or Raw

Facts)ProcessingOutput (Information or

Processed Facts)Storage

What does a computer do? Performs the processing cycle by

sending electric signals through circuits contained on small silicon chips inside the computer. Circuits rarely failSignals travels at near the speed of lightProcessing can be completed in billionths

of a second (nanoseconds) People who use the computer or the

information it provides are called users or end users.

How does a computer work? Must have a detailed set of

instructions (program or software)

Program is stored temporarily in the computer’s memory while in use.

Once stored, the computer begins executing one instruction after another until the program or job is complete.

Primary Components

CPU

Memory

Output

Storage

Input

Input devices

Components that allow users to enter data, programs, commands, and responses.

Input devices Keyboard

DesktopNotebookHandheld

MouseMechanicalOpticalControls the movement of a

pointer Others (joystick,

microphone, camera, etc…)

The central processing unit (CPU)

Electronic components that cause processing to occur

Speed is measured in Gigahertz

Made up of 2 main partsControl unitArithmetic Logic Unit (ALU)

Memory Also called RAM (Random Access Memory),

“primary storage”, or “temporary storage” Electronic components to store data and

programs while in use Is volatile (contents are lost when power is

turned off) Storage capacity described in terms of

bytes1 byte = 1 storage location (1 character)1 kilobyte (KB) = 1,000 storage locations1 megabyte (MB) = 1 million storage locations

(approx. 500 pages of text)

ROM (Read Only Memory)

Stored on components inside the computer

Non-volatile Contains hardware specific

programs and instructions, such as those used to start the computer when it is first turned on

Output devices

Hardware that makes the information resulting from processing available for use

Printers Output is called hard copy Impact printer

images formed by striking an inked ribbon against the paper

Dot Matrix Printer Nonimpact printer

Higher quality text and graphicsQuieterColor capabilities

Inkjet printer (nonimpact)

Drops of ink are sprayed onto the paper

Speed measured in pages per minute (ppm)

Laser printer (nonimpact) Laser beam creates a charge on a drum

that attracts a special ink (toner). As the drum rotates and paper passes

under the drum, ink is transferred from the drum to the paper.

The ink is then fused to the paper using heat and pressure.

High quality black and white or color output.

Speed measured in pages per minute (ppm)

Computer Screens Also called screen, monitor, or CRT Produces soft copy LCD technology is used in notebook,

handheld, and flat panel displays Composed of individual picture

elements (pixels) Quality depends largely on 3 things

resolution dot pitchrefresh rate

Storage Devices

Also called “auxiliary storage” or “secondary storage” devices.

Long term, non-volatile.

Floppy disk Portable – can be moved from

floppy disk drive on one computer to another

Inexpensive3.5” diskette is most popular todayHolds 1.44MB of dataConsists of a thin, flexible magnetic

coated disk encased by a hard plastic shell.

Data is stored as magnetic patterns

Hard disks Most are installed inside

the computer and cannot be removed

Consists of 1 or more rigid metal platters with a coating that allows data to be stored magnetically

Storage capacity is usually measured in Gigabytes (1 billion bytes)

Formatting Prepares a disk

for reading and writing

Organizes the disk into storage locationsTracks: narrow,

circular bandSectors: pie

shaped wedges

Access time

The time needed to access and retrieve data from the disk

Measures the performance capability of a disk drive

Access time for floppy disk is much slower than that of a hard disk

Compact Disks

CD-ROM (compact disc read-only memory)

Uses laser technology to store large amounts of information

Can contain text, graphics, and video

CD-ROM

Data is written to a CD-ROM by the manufacturer

Contents of the CD-ROM are read-only (data can not be written to the CD-ROM)

Capacity is around 650MB

CD-R (compact disk – recordable)

Users can write to this disk, but cannot erase anything from the disk

Requires a special CD drive capable of writing to CDs

CD-RW (compact disk – rewriteable)

Data can be written, erased, and rewritten

Requires a special CD drive capable of writing to CDs

DVD-ROM (digital video disk)

Very high capacity (4.7GB – 17GB) Requires a special drive capable of

reading a DVD disk The drive is also capable of reading

CDs

CMP 101 Computer Essentials Part II

Computer Software

Software

Set of instructions that tell the computer exactly what to do

Categorized into two typesSystem softwareApplication software

System software Consists of programs (instructions) that

control the operations of the computer hardware

Operating System Important subset of system softwareConsists of programs that tell the computer

how to perform various basic functions Loaded into memory during the boot processMost personal computers use an operating

system with a graphical user interface (GUI)

Application software

Programs that tell the computer how to produce information

Word Processing software Spreadsheet software Database software Presentation software

Network A collection of computer hardware connected via

various different communications media Allows users to share information and resources

LAN (Local area network)

WAN (Wide area network)

The Internet The world’s largest

network A worldwide collection of

networks Has a variety of uses

Electronic messages (e-mail)Accessing informationShoppingMeeting other peopleEntertainment

Connecting to the Internet Internet service

provider (ISP) – a company that supplies access to the internet for a monthly fee.

Online service – provides many other specialized services in addition to internet access

The World Wide Web A popular subset of the Internet Made up of billions of documents (Web

Pages) that contain text, graphics, video and/or audio.

Organized into individual sites that contain a collection of related web pages.

Web pages are viewed using a special program called a Web Browser

Each web page has it’s own unique address called a Uniform Resource Locator (URL)

E-commerce Business to consumer

(B2C) sale of goods and services to the general public

Consumer to consumer (C2C)

one consumer selling directly to another

Business to business (B2B) sale of goods an services to other businesses

CMP 101 Computer Essentials Part III

Purchasing and Maintaining a Computer

How to purchase a desktop computer

Determine your needs

Do some research Talk to others about

their purchases Read reviews in

magazines and newspapers

How to purchase a desktop computer

Consider purchasing optionsLocal educational facilitiesLocal dealersMail order / Telephone / Internet

Compare prices by summarizing hardware components, software, and service options from each potential vendor

Be aware of other costs (furniture, training, paper, diskettes, CD’s, ink cartridges, etc…)

How to purchase a desktop computer

Other considerationsAsk about restocking feesObtaining Internet access Is the computer compatible with

computers you use elsewhereExtra service agreements

Purchase with a credit cardAvoid purchasing the smallest computer

available.

Maintaining a Personal Computer Start a notebook to record import

information about your computer. Keep the area around the computer clean Back up important data Protect your computer from viruses using

an anti-virus software Routinely run maintenance software

included with the computer (Scan disk, disk defragmenter, etc…)

Refer to your user’s manual for more information on maintaining your system