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 Unit  Keyboard  Mouse  Monitor  Printer

What does a computer do? The Information Processing Cycle:  Input (Data or Raw Facts)  Processing  Output (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 fail  Signals travels at near the speed of light  Processing 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  Desktop  Notebook  Handheld Mouse  Mechanical  Optical  Controls 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 parts  Control unit  Arithmetic 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 bytes  1 byte = 1 storage location (1 character)  1 kilobyte (KB) = 1,000 storage locations  1 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 graphics  Quieter  Color 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 pitch  refresh 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 Inexpensive 3.5” diskette is most popular today  Holds 1.44MB of data  Consists 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 locations  Tracks: narrow, circular band  Sectors: 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 types  System software  Application software

System software Consists of programs (instructions) that control the operations of the computer hardware Operating System  Important subset of system software  Consists of programs that tell the computer how to perform various basic functions  Loaded into memory during the boot process  Most 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 ( )  Accessing information  Shopping  Meeting other people  Entertainment

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 options  Local educational facilities  Local dealers  Mail 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 considerations  Ask about restocking fees  Obtaining Internet access  Is the computer compatible with computers you use elsewhere  Extra service agreements Purchase with a credit card  Avoid 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