Ch. 1: Defining Information Technology
– Learning the language of IT
• Acronyms: GUI, WYSIWYG, etc.
• Jargon
–“bit bucket”, “Right-click”, “hashtag”
–http://www.unc.edu/~macmw/jargon.html
• Metaphors and Virtual Worlds
–Everyday terms like “window”, “desktop” ,
“menu”, “ribbon” have special meanings.
–A metaphor is a familiar concept/item that
helps us to understand a new concept/item.
Example Acronym: WYSIWYG
• "What you see is what you get "
• Text is stored in computer memory as long
line of letters, numbers, punctuation,
control characters, etc.
• Original text editing software could not
display formatting; users had to guess
what it would look like when printed
(Similar to HTML).
• WYSIWYG process displays data as a
formatted page – “Print Preview”
Why Know The Right Word?
• There are many new terms in IT
– Terms are invented for ideas, concepts
and devices that never existed before
– Some words are redefined or have multiple
meanings
• Use the right word at the right time
whenever possible.
• Concepts – explain in own words, use
terms as you become familiar with them
Why Know The Right Word? (cont'd)
• Terminology is basic to learning a
new subject
– Words represent ideas and concepts
– Precision in word use represents precision
in understanding ideas
• Communicating with others
– To ask good questions and receive help
– email, by telephone, helpdesk, built-in and
online help facility (spelling!), in class, etc.
Computers Are Everywhere
• WWII – Computers were people!
• Many types: component/desktop, laptops,
tablets, smart phones, music players, wireless
mic’s, cars (anti-lock brakes, etc.) TV remotes,
credit card readers. Others?
• General Purpose vs. Specific and/or Locked
– Computers run software
– Commercial (COTS), Custom, In-House, Hobby
• Open Source vs. Proprietary
Hardware, Software, ‘Experience’
• Hardware: historically a term for metal items
used in construction
– Now also refers to physical parts of a
computer (and other technology)
– Functions implemented directly with wires
and transistors. Hard to change.
• Software is a term created for computers
– Means programs or instructions the
computer follows to do “almost anything”.
– Applications vs. Folders & Files (Data/Info)
Software
• Software Stack (on “top” of hardware)
– Concept used to structure and organize the
software in contemporary computer systems
– “Layers” that support user applications.
– Each layer implements functionality used by layers
above.
– Software instructs an agent to perform some
function or action by giving a step-by-step process.
– The agent is anything that can follow the
instructions or “software program”.
– For software professionals, the agent is a
7
computer. (Recall – people as computers.)
Software Stack
8
Hardware: Where's the Start Button?
• Many computers are left on most of the time
– Smart Phones? (Turn Off in class!)
– Screen savers prevent(ed) “burn-in”
– Computer is reactivated by moving or clicking
mouse, or pressing a key. (Feedback?)
– Sometimes computers may be off (labs)
– May need to boot (turn on). Careful!
Boot
• Booting: Start computer
• Rebooting: Re-start computer
• Boot instructions (special program or
initialization software) are stored in a
microchip called the boot ROM
– ROM is Read-Only Memory
• From “Pulling yourself up by your own
bootstraps AKA ‘BOOTstrapping’"
Cables
- connect components to computer and to
power. They need to be plugged in correctly! Sockets
and plugs are labeled with icons. May be color coded
Newer: Wireless (BlueTooth, WirelessUSB, etc.)
Hardware: The Monitor
• Interactive video screen (CRT, LCD, etc.)
• Displays information stored in computer memory or
special video memory
• Grid of small units called pixels
– (picture elements )
• Computer draws each pixel in the designated
color for the image or figure
• The more pixels in each row and column, the
smoother and crisper the image
• “High resolution”
• RGB
– Primary colors
of light
– Red
– Green
– Blue
– Other colors
created on
screen by
combining
different
amounts of
primary colors
Colors
Motherboard
• Printed circuit
board inside
System Unit.
• Contains most
of the circuitry:
• microprocessor
chip (or Central
Processing Unit
– CPU) and the
memory
• May be shielded
against interference
Hardware: Microprocessor
• "Smart" part of system
• Performs actual computing
• "Micro" was adopted around 1980 to
distinguish single chip circuitry from larger
mainframes of the day.
• Term is somewhat archaic. Perhaps
more correct to say “processor” or CPU.
• Latest Systems have Multi-Cores
Hardware: Memory
• Where program(s) and data are located
while programs run
• RAM: Random Access Memory
• PC’s contain millions or billions of bytes
of RAM: Megabytes (MB) / Gigabytes (GB)
• What Random Access means:
– Any item can be retrieved directly
– Unlike sequential access
– (example: Tape vs. CD or DVD)
Hardware: Hard Disk (HD/HDD)
• High-Capacity, persistent peripheral
storage device
– Stores programs and data not in immediate
use by computer
– Made from magnetized iron compound
– Information remains if PC is on or off
– Called permanent or persistent storage
– Also called secondary storage
– Newer: Solid-State Drive (SSD)
Saving from RAM to Hard Disk
• Saving moves information from RAM to
hard disk
• Successful users save frequently !!!
– Make multiple copies/backups
• Most RAM memory is volatile
– Information is lost when power turns off
– If computer fails or power-cycles, only data
on the hard disk may survive
• HD can also fail – Have
Backups !!!
Experience
• People:
– meet online and marry
– make unfortunate posts and lose their jobs
– spend hours on music, videos, games, etc.
• Most interactions w/computers are
recorded, virtual, or artificial
• Recorded technology - Oldest form of IT
– Recording a scene, performance, event, etc.
– Digital copies are approximations of reality
– With today’s technology, in most cases the
approximation is extremely accurate
Digital Information
• Transformation
– Easy to enhance or embellish digital information
– Photo editing, video editing, audio remixing, etc.
– Don’t believe your lying eyes!
– Photoshop has become a verb
• Synthetic Complexity
– Creation of new digital media: info. is synthesized
– An alternate version of the world
• Examples: animations, cartoons, video games
Digital Information
• Synthetic Complexity: Advantages?
– Early animation: Each frame drawn by a
person and the music recorded “live”
– Contemporary animation: Also created one
frame at a time, but by a computer
– A “start scene,” an “ending scene,” and
directions on how to modify the start to get
to the end are processed by the computer
to create the movie. Edited/Touch-Up.
– Digital sounds are added and synchronized
to the images
Virtual Worlds
• Virtual reality: a world created by computers
to simulate the physical world
• It is not “real”, but is perceived “as if” it were
• The full VR experience is still under
development…but we see it all the time:
– Keypads on a smart phone display
– Spreadsheet software that look like
accounting paper
– GPS displays that show a map
– Familiar mixed with new/inventive
Artificial Worlds
• Systems like iTunes, Facebook, Twitter, and
Angry Birds are entirely new products of
human imagination. Or are they?
• Did/Do creators have unlimited flexibility?
• This flexibility to create (almost) anything is
one of the exciting aspects of computing
• Extended Abilities. Software can often do
difficult tasks in a more user-friendly way.
• Not the standard techniques used previously
• New “experts”. Example: video editing
Artificial Worlds
• New Phenomena: Twitter, Facebook, YouTube
– Experiences that did not exist before they were
created, at least in scale and pervasiveness.
– Some aspects, such as communication via phone
and snail/email, did exist, but much more limited.
• New (?) Problems
– New privacy concerns (also Opt-in vs. Opt-out)
– Negative issues of scale
– Spam ( junk mail )
– Scams (Nigerian Widow fraud)
– online bullying and stalking
Data and Information
• Some say ‘Data’ and ‘Information’ are
interchangeable words in computing
• Better: Information is processed Data (“value
added”). Relative comparison.
• Represented as bits (0’s and 1’s)
• Digital information is stored on Web and
Internet servers as files and databases
• Databases are everywhere
– Digital music (for example, iTunes)
– Photo databases
– Email and smart phone contacts, etc.
WWW: Sourced vs. Social Content
• Sourced content: produced for commercial
purposes or to disseminate information.
• “Newspapers”, Government, Business, etc.
• Entirely(?) controlled by 1 organization/person
• Social content: created by visitors to the site
• Social networking, media sharing, gaming,
and reference
• Users generate much of the content
• Mix? Search engines (Google)? Other?
Words for Ideas: Algorithm
• Algorithm: A Precise and systematic method
for solving a problem or producing a
specified result.
– (Discussed in more detail in later chapters!)
– We use and invent algorithms all the time :
• Arithmetic operations
• Sending a greeting card
• Searching for a number in a phonebook
• Creating and Following a Recipe
• Other
Algorithms and Programs
• Writing out the steps of an algorithm is
part of programming
– A Program is one or more algorithms,
specialized to a specific set of conditions &
assumptions, written in a specific
programming language.
• “Clueless Computers” need to be told precisely
what to do: everything must be spelled out
• People do have a clue, so many things can be
left out of an explanation when people have to
follow directions or an algorithm.
Words for Ideas: “Abstract”
• Abstract: To Extract (“Remove” ) the basic
concept, idea, or process from a situation.
(Hide irrelevant details)
• Abstraction is a more succinct and generalized
form of the original concept.
– For example: parables and fables
• the moral is abstracted from the story
– Decide which details are relevant
– Understand and apply the abstraction to other
cases or situations
"Generalize"
• Process to recognize common idea(s) in two
or more situations
• Summarize expression of an idea, concept, or
process that applies to many situations
– e.g., faucet handles usually turn left for on and
right for off
– Caps usually twist left to loosen, right to tighten
• Remember that generalizations will not apply
in every single situation - Do not be too
general!
"Operationally Attuned"
• Being aware of how a device or app works
• Apply what we know about how device or
system works to simplify use
– e.g., cap lids usually twist left to loosen, so we
are confident about which way to twist if stuck
– We know this intuitively, but knowing it explicitly
makes us operationally attuned
• THINKing about how Information
Technology (IT) works can make it simpler to
use that technology. THINK (IBM slogan)
"Mnemonic"
• Memory aid
– Often pronounceable words and phrases:
– Spring ahead; Fall back
– PILPOF - Plug in last, pull out first
• May Help simplify use of technology
– Easy memorization of infrequently
used details
– Can be overused, like Acronyms (LOL)
Analytical Thinking
• Using specific facts and comparisons
to back up statements.
• Non-analytical statement:
– World record in the mile run has improved
• How much? Compared to what?
• How does this compare to other accomplishments?
• Analytical statements:
– In 45 years, the world record in the mile improved
from 3.59.4 to 3.43.13,
a 7% improvement
– The average 20 year old can run a mile in 7.5
minutes. The world record holder is twice as fast.
Benefits of Analytical Thinking
• Learning specific facts, and comparing
them to other specific facts
• Putting things in perspective
– 7% historical improvement in mile run record
compared to 100% difference between world
record holder and average person
• Increased clarity and focus on facts
• Evidence for statements and ideas
Super Computers
• Analytical comparison of computer speeds
– UNIVAC I
• First commercial computer released in 1951
• Rate of 100,000 addition operations (adds) per second
– 2010's Computers
• Inexpensive laptop/palmtop systems
• Rates: billions of adds per second
• Factors of 10 – 100 thousand improvement over
UNIVAC
– IBM Sequoia
• As of 2012 IBM Sequoia is the fastest in the world
• Rate of 16.3 Quadrillion floating points (decimal) adds
per second
• Factor of 163 billion improvement over UNIVAC