Transcript Understanding Essential Computer Concepts

Understanding Essential Computer
Concepts
Computer Applications 1
Definition of a computer
 A computer is an electronic machine that
receives, processes, stores and delivers
information.
 Computers are classified by:
 Size
 Speed
 Capabilities
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Types of Computers
Types of computers include (but are not limited to)
1. Personal computers
Desktop
Laptop (notebooks)
Tablet PC
2. Hand-held
PDA’s (personal digital assistants)
MP3 players
Cell phones
3. Mainframe computers
4. Supercomputers
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Computer System Components
Computer systems include hardware and software
 Architecture or configuration is the design
and construction of a computer
 Specifications are the technical details about
each hardware component
 Data refers to information (words, numbers,
graphics, etc.)
 Processing is modifying data
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Computer Systems Components
(continued)
 Motherboard is where processing tasks occur
 Main electronic component
 Is a circuit board
 Microprocessor (CPU)
 Transistors and electronic circuits on a silicon
chip
 Mounted on the motherboard
 Responsible for executing instructions to
process information
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Microprocessor Speeds
 Microprocessor speeds depend on:
 Speed of the microprocessor (clock speed, word size and cache size)
 Whether single or dual core
 Clock speed is measured in megahertz (MHz), millions of
cycles per second or gigahertz (GHz), billions of cycles per
second
 Word size refers to the amount of data that is processed at one
time
 Single core processor has one processor on a single chip
 Dual-core processor has two processors on a single chip and
can process information twice as fast
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Computer System Components
(continued)
 Cards are removable circuit boards to expand the capabilities of
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the motherboard
Input is the data or instructions you put into the computer
Output is the results of the computer processing
Peripheral devices such as mouse, keyboards printers and
storage devices accomplish input, output and storage functions
Commands are input instructions
Examining Input Devices
 Keyboard
 Can be ergonomic
 Mouse
 Pointing device
 Rolling ball or optical
 Clicking commands
 Scroll wheel
 Touchpad
 Pointing stick
 Scanner
 Microphones
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Examining Output Devices
The Monitor displays the output from a computer
 Flat panel monitor uses LCD (liquid crystal display)
 CRT (cathode ray tube) monitor uses gun-like devices that
direct beams of electrons toward the screen to activate dots of
color
 A graphics display divides the screen into a matrix of small dots
called pixels
 Resolution is the number of pixels the monitor displays.
Standard resolutions range from 640 x 480 to 1600 x 1200.
 Dot pitch (dp) measures the distance between pixels. (.28 or
.26 dp is typical)
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Output Devices (continued)
 To display graphics, a computer must have a graphics card,
also called a video display adapter or video card.
 Speakers
 Like input devices, output devices can be connected to a
computer using cables or a wireless connection
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Output Devices - Printers
Printers produce a paper copy often call
hard copy
 Laser printers – a temporary laser image is
transferred onto paper with a powdery
substance called toner
 Inkjet printers – spray ink onto paper
 Dot matrix printers – transfer ink to the
aper by striking a rubbon with pins.
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Investigating Data Processing
All data and programs are stored as files
 A file is a named collection of stored data
 An executable file contains the
instructions that tell a computer how to
perform a specific task
 A data file is created by a user with
software
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Investigating Data Processing
A computer cannot understand characters used in human
language
 Like a light bulb, a computer interprets every signal as
either “on” or “off ” . These numbers are referred to as
binary digits or bits
 A series of eight bits is called a byte
 A kilobyte (KB or simply K) is one thousand bytes
 A megabyte (MB) is one million bytes
 A gigabyte (GB) is one billion bytes
 A terabyte (TB) is one trillion bytes
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Binary Representations of Numbers
Number
Binary representation
0
00000000
1
00000001
2
00000010
3
00000011
4
00000100
5
00000101
6
00000110
7
00000111
8
00001000
:
14
253
11111101
254
11111110
255
11111111
Investigating Data Processing
Personal computers commonly use the ASCII
(pronounced ASK-ee) system which stands
for the American Standard Code for
Information Interchange
 Computers translate ASCII into binary data
so they can process the data
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Sample ASCII code representing letters
and symbols
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Character
ASCII Code
Binary Number
(space)
$
32
36
00100000
00100100
A
B
A
65
66
97
01000001
01000010
01100001
B
?
£
®
98
129
163
217
01100010
10000001
10100011
11011001
É
233
11101001
Understanding Memory
Types of memory include the following:
1. Random access memory (RAM) –
 temporarily holds programs and data while the
computer is on and allows the computer to access
that information randomly.
 Consists of chips on cards that plug into the
motherboard.
 When the computer is off RAM is empty
2. Cache memory (RAM cache or CPU cache) –
 Special high speed memory chip on the motherboard
that stores frequently accessed and recently accessed
data and commands
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Understanding Memory
3. Virtual memory – space on the computer’s storage
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devices that simulate additional RAM.
 It is much slower than RAM
4. Read only memory (ROM) – is a chip on the
motherboard that has been prerecorded with data that
gives instructions (BIOS or basic input/output system)
used to check the computer system’s components to
make sure they are working and to activate the
essential software that controls the processing function
when the computer is turned on or booted up.
 ROM never changes and it remains intact when the
computer is turned off. It is called non-volatile or
permanent memory
Understanding Memory
4. Complimentary metal oxide semiconductor
(CMOS, pronounced “SEE-moss”) memory – chip
installed on the motherboard that is activated during
the boot process and identifies where essential
software is stored.
 A small rechargeable battery powers CMOS so its
contents are saved when the computer is turned off.
CMOS changes every time you add or remove
hardware on your computer system but does not
empty when the computer is shut off
 The date and time are stored in CMOS
 Often referred to as semi permanent memory
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Understanding Storage Media
The types of storage media are:
1. Magnetic storage devices
 Hard disk – magnetic oxide-covered metal platters
sealed inside the computer
 Tape – used to make back-up copies of data stored on
hard drives
2. Optical storage devices – polycarbonate discs coated
with a reflective metal on which data is recorded using
laser technology
 CD (Compact disc) – can store 700 MB of data
 DVD- can store between 4.7 and 15.9 GB of data
 Blu-ray discs and HD-DVD – can store between
15 and 50 GB of data
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Understanding Storage Media
3. Flash Memory
 Flash memory cards – used in digital
cameras, handheld computers and other
devices
 USB flash storage device – can store 32
MB – 16 GB of data. Popular for use as a
secondary or backup storage device for
date stored on a hard disk drive
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