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