Lecture01_Introx - Computer Science @ Millersville University

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Dec 13, 2013 (4 years and 19 days ago)

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Lecture
1

Defining Information Technology

Computers


What is a computer?



General purpose device that is programmable



Electronic



Transform data



Data


Stored as bytes (B)


1 B can represent one character (usu.)


Kilobyte (KB) ~= 1e3 B


Megabyte (MB) ~= 1e6 B


Gigabyte (GB) ~= 1e9 B


Terabyte (TB) ~= 1e12 B


Petabyte (PB) ~= 1e15 B


Exabyte (EB) ~= 1e18 B

Hardware

and Software


Computing concerns data and



Hardware



Software


Hardware


Input/Output

devices



Processor (CPU)


Control Unit


Arithmetic and Logic Unit



Memory (RAM)


Capacities?

Hardware


Storage


Hard Disk Drive



Solid State Drive (Flash)



Capacities
?



Software


Software



P
rograms that instruct computers in the steps
needed to implement applications



Intangible


Software


Hardware and software present a
virtual

world that we experience


Synthetic, intangible



Facebook


Bejeweled Blitz


Wikipedia


Call of Duty Black Ops




Computers Are Everywhere


In laptops
, tablets, smart
phones, music
players,
wireless
mics, anti
-
lock brakes,
TV remotes, credit card readers,
etc.



Through
2010, 24.1 billion ARM processor
chips have been
shipped



It
means that every consumer in the
developed world owns
more than a
dozen

Computers Are Everywhere


Head
-
to
-
Head Comparisons


Inside a Smartphone

Figure 1.2 Top side of the main printed circuit board in the iPhone 3GS; for
orientation, the USB port is at
left. CPU by Samsung. Flash by
Toshiba.

Inside a Smartphone



iFixit


http
://
www.ifixit.com/Teardown/iPhone+5+Tea
rdown/10525/1



Software


Software is a collective term for programs



Programs consist of instructions



Programs “instruct” the computer
(hardware)

Software


Software Stack


Concept used to structure and organize the
software in computer systems



Series of layers of programs that implement
user applications



Each layer implements operations used to
build the layers above

Software

Software


Referring to figure on the previous slide:


To
check out
a video on YouTube video using
a
smart phone, you
would:


use
the
browser

application
to
get
to
YouTube


the
browser

app uses the
window manager
, and
several
other frameworks


the
window manager
uses
media manager
, and
several other libraries


the
media manager
uses the
display

drivers
, and several other
kernel operations

Software


Writing software is challenging



Word


Photoshop


Windows 7

The Data


Data and Information are (usu.)
interchangeable words


Physical Form


Information is everywhere in the physical
world


Much of it can be captured and digitized


It is always represented as bits

(0’s and 1’s), 8 of which form a byte

The Files and Databases


D
igital information we access through
WWW is stored on Web servers around
the world as files and databases.



Database examples


iTunes library


Phone contact list


Note SQLite library in software stack

Terms of Endearment


To learn a new subject, we must learn its
terminology



Helps when you search or call tech
support too!

Algorithms


Computer Science


Study of
algorithms


P
recise, systematic method for producing a
specified result


Important points about algorithms


We use and invent algorithms all the time to
solve our problems (examples?)


Often the agent that “runs” the algorithm is a
person, NOT a computer

Algorithms (cont’d)


Computers are clueless



Everything
needs to be spelled out



Programmers make algorithms precise by
writing them in a programming language

Algorithms (cont’d)


People
do
have a clue, so many things
can be left out of an explanation when
people

have to follow directions



E.g., directions to the lab


Algorithm Versus Program


Programs


C
onsist of many algorithms



Written in a specific programming language



Often use terms interchangeably

Key Concept Terms


Abstract

and
Generalize


Abstract


Remove the essential from the nonessential


Way no manage complexity



Fables require
a
bstraction


Abstract essential point to learn from it


“Tortoise and the Hare” fable


Key Concept Terms


Generalize


Process to recognize the common idea in two
or more situations



E.g.


F
aucet handles usually turn left for on, right for off


Caps are same way


Leads to “Lefty
loosey
, righty
tighty