Computer Applications for Business Chapter 1-8 (minus 6)
ASCII
(American Standard Code for Info. Interchange) 7-bit code for the characters
GIF
(Graphics Interchange Format) standard encoding for icons, cartoons, and simple art (loseless)
HTML
(Hypertext Markup Language) main language used to define how a web page should look
ISP
(Internet Service Provider) sells connection to the internet → phone companies and cable companies
LAN
(Local Area Network) when computers are close enough to be linked by a single cable or pair of wires → the interconnection is referred to as this
TCP/IP Protocol
(Transmission Control Protocol/Internet Protocol) sending process
WANs
(Wide Area Networks) networks designed to send info. between 2 locations widely separated and not directly connected
Properties of Algorithms
1) Input specified 2) Output specified 3) Definite 4) Effective 5) Finite
crawler
1st step: software that does the crawling; has a To Do List of URLs that it's given to begin with; builds an index
unicode
256 extended ASCII codes over most Western languages; represents many more characters by using up to 32 bits to code characters
query processor
2nd step: looks up the tokens (search terms) in the index and returns a hit list
tertiary sources
3 levels removed from the person with the direct knowledge of the event
Required HTML Tags for Web Pages
<!doctype html> <html> <head> </head> <body> </body> </html>
structure tags
<div> Divides HTML document into sections <span> Grouping attribute <p> Paragraph <h1> through <h6> Heading styles
definition lists
<dl></dl>; it's made up of definition terms <dt></dt> and definition data <dd></dd>
top-levels heading tags
<h1> general description of a section of a document's content
span
<span> surrounds content that we want to style in a certain way -- <span style="color:blue">Mo</span>
table
<table></table> Border around it: Table row tabs: <tr> </tr> Cells of each row <td> and </td> Captions: <caption> and </caption>
title
<title> tags enclose a short phrase describing the whole page
unordered lists
<ul> and </ul> surrounds the items of the list which are themselves enclosed in list tags <li> and </li>
Abstraction
A general concept formed by extracting common features from specific examples Determine irrelevant from relevant
Algorithm
A precise and systematic method for producing a specified result
Cache
A small amount of memory
ARM Processor
Advanced RISC Machine Reduced Instruction-Set Computer Specialized to be part of other systems
Hardware
Built out of wires, rollers, and motors Computer machinery and equipment
Box Model of CSS
CSS considers every HTML5 element to be enclosed in a "box"; can clearly visualize content, padding, border, and margin
Photolithography
Chip makers "print" the wires and all other parts onto the chip
Software
Collective term for programs "Instructs" the computer hardware by providing the steps needed to perform a task
Tim Berners-Lee
Created a "home page" where everyone could access documents, images and other resources of CERN (the agency Tim worked for) allowing rapid dissemination of information This used the famous HTTP, where a page using the HTTP protocol , your browser (the client) and the host (Web server) know exactly how to interact
Herman Hollerith
Credited with the first "production" application of digital information with his application for the U.S. Census Bureau
DNS Servers
Domain Name System translates the hierarchical, human readable names into the four number IP addresses → both people and computers to use their preferred naming
Moore's Law
Gordon Moore; a computer of a given capacity needed fewer and fewer chips as the years went by, and therefore became cheaper and cheaper So inexpensive, in fact, that everyone could afford a personal computer
domain names
Human readable symbolic names for computers that are based on a hierarchy of domains
Processor
Includes CPU, a small amount of memory usually called a cache, and is connected to some input and/or output devices
Programming
Instructing an agent to perform some function or action by giving a step-by-step process "Agent" being anything that can follow directions
Transistor
Invented by John Bardeen, Walter Brattain, and William Shockley in 1947 which had three superior properties: Low power (less heat) Extremely reliable Small in size and weight Allowed computers to become much smaller, extremely reliable, very cheap, and have much more complex CPUs
Broadcast
Involves a single sender and many receivers (radio and television)
Effective
It is within the "abilities" of the agent following the instructions
Campus or Enterprise Network
LAN → organizations' system administrators connect the computers to form a LAN
Integrated Circuits (ICs)
Monolithic blocks (chips) made of silicon and closely related elements in which both active parts like transistors and connective parts like wires are fabricated together in a multistep process
server name
Name is the server IP address given by the domain hierarchy→ computer uses this name to send a request to the server computer for the page
point-to-point
Opposite of the other two → telephone communication and text message because there is one specific sender one specific receiver
Central Processing Unit
Performs instructions stored in the computer's memory Executes commands from a computer's hardware and software; the principal computer chip that contains several processing components, which determines the computer's operating speed; the "brain" of a computer
Layered Software Development Advantages
Programmers can use the software without ever understanding how those programs work, beyond knowing the proper way to use them. They are building on the work of thousands of other programmers, who have contributed to these layers As technology advances, more boxes will be included and more layers will be added. Over time, the stack grows, both in terms of components and layers
Advantages of Software>Hardware
Programs can be changed rapidly, simply by loading new instructions into the memory Programs can be much more complex, being limited only by the size of the memory Computations are autonomous, meaning that they can run on their own without a person attending to them
Rebooting
Restart a computer
Linear Search Algorithm
Sequentially look for a data item in a list Return -1(or null) if reaches end
Booting
Start a computer
types of communication
Synchronous (Voice, phone), Asynchronous (Email, Text), Multi Cast, Broadcast, Point to Point Unicast
Key Ideas*
The CPU and soft instructions allowed a machine to do more complex computations, and to accomplish them autonomously Integration and photolithography all but eliminated the complexity of building electronic devices Layered software developments allows programmers to build on the work of thousands of others without the need to understand the operation of their computations--only how to use them--and then others will build on their work
Finite
The agent will eventually finish the computation, giving the right answer, or stop and report that none is possible
Programs
The instructions computers perform to implement applications A collection of computer instructions that implement a function or action
le mot juste
The right word or phrase
Generalization
The statement that sums up the overall idea
Definite
The whole process is spelled out unambiguously
multicast
There are many receivers, but the intended recipients are not the whole population (ex: magazines often covering specializing topics)
Operationally Attuned
To apply what we know about how a device or system works to simplify its use
Generalize
To express an idea, concept, or process hat applies to many situations
Abstract (used "to abstract")
To remove the basic concept, idea, or process from a situation
Specifying Input & Output
To say what the computation is given as data, and what it will produce as a result
What was the "game-changing" substitute for vacuum tubes?
Transistors
URL
Universal Resource Locator
Software
Written programs or procedures or rules and associated documentation pertaining to the operation of a computer system and that are stored in read/write memory
domains
a related group of networked computers
IP (Internet Protocol) Address
a unique address each computer connected to the internet gets → series of 4 numbers (one byte each) separated by dots (0-255)
wireless networks
a variation on the LAN connection is often referred to by its protocol name 802.11
black color
absence of light (all 0's)
caching
act of saving info. for possible reuse soon
attribute
additional input specification for the tag
escape symbol
ampersand (&) followed by an abbreviation, followed by a semicolon (ex: < displays as < ; > displays as > ; & displays as &)
metaphor
an icon or image used as representative or symbolic of a computation
hyperlink
anchor text (text in the current document which is highlighted) and the hyperlink reference (address of the other webpage)
feedback
any indication that either the computer is still working or has completed the request → takes many forms, depending on what operation a user has commanded
new instance
any specific piece of info. (image, month, or document) is considered an instance; structure w/o any properties or content filled in
binary #s compared with decimal #s
binary numbers are limited to two digits 0 and 1
Styling/Format Tags
bold: <b></b> italic: <i></i> paragraph: <p></p>
navigation bar
built using an unordered list of links ul {list-style-type:none; margin:0; margin-left:140px;padding:0;}
Markup Validation Service
checks to make sure the XHTML is perfectly correct → if wrong the service tells you where the mistakes are and whats not proper
search engine
collection of computer programs that helps us find info. on the Web
MPEG
compression scheme of the Motion Picture Experts Group of ISO
root name servers
computer s that know the IP addresses for the top-level domain
Perfect Reproduction
computers encode info. as a sequence of binary digits, 0's and 1's → digital information (only use 0's and 1's means it can be perfectly reproduced)
the cascade - sources for style info.
default - comes with the browser; external - styling a file; style section - defined inside of <style> tags; inherited - properties set by enclosing tag; tagged - defined with the style attribute
relative reference
describes how to find the referenced file relative to the file in which the anchor tag appears
intensities
different amounts of light
Top-Level Domains (TLDs)
edu domain for educational institutions is one of several top level domain names → ex: commercial enterprises (.com), .edu, organizations (.org), networks (.net), military (.mil), governmental agencies (.gov)
white
full intensity of each color Binary: all 1's Decimal: (255, 255, 255) Hexadecimal: FF, FF, FF
alt attributes
gives textual description of a picture
primary source
has direct knowledge of the info.
Packets
has space for one unit of info., a destination IP address, and sequence # → sent over the internet one at a time using whatever route is available
IP Packet
has the IP address of the comp being contacted and the return IP address (like a postcard); also has a sequence number (a few bits used for technical purposes and a payload)
hex notation
hex digits that are base 16 numbers; used to specify an RGB color or other encoding using bits → we must give the bits in order
brightness
how close to white the pixels are
URL Parameters
info. added by a client to a URL when it connects to the server (info. following the question mark)
metadata
info. describing info.
AND-query
instructs the query processor to find pages relevant to all the words; there is no index entry corresponding to a set
index
list of tokens that are associated with the page
intranet
local networks that connect to the internet by a gateway
OR-query
logical operator; hits on pages that are associated with one (at least, but possibly more) of the words
site search
looking only on their site
JPEG (Joint Photographic Experts Groups of the ISO)
lossy compression technique that exploits same kinds of "human perception" characteristics for light and color
ethernet
main technology for LAN → setting up connection on all computers in a lab or building
PandA
mnemonic for presence and absence- describes info. that is "black" or "white"
Extended ASCII
now called: ISO-8859-1; an 8-bit code; 2 to the 8th = 256 symbols; byte
bit depth
number of bits used to represent each sample
PageRank
order in which hits are returned to a query
lossy compression
original representation cannot be exactly reconstructed from the compressed form
loseless compression
original representation of 0's and 1's can be perfectly reconstructed from the compressed version
secondary source
people who interviewed primary sources
channel
physical setup for an Ethernet network is a wire, wire pair, or optical fiber
router
physically connected to an ISP modem connected which is capable of broadcasting and receiving signals such as radio frequency (RF)
absolute reference
references using a full URL
Synchronous communication
requires that both the sender and the receiver are active at the same time ex: sending or receiving simultaneously
Nyquist rule
sampling rate must be at least twice as fast as the fastest frequency
page's pathname
sequence following the IP address: /homes/Snyder/index.html → tells the server which file or page is requested and where to find it
software stack
series of layers of programs that implement user applications (user > software > hardware > device)
CSS (Cascading Style Sheets)
simplifies the task of creating beautiful yet complex page designs
contrast
size of difference between darkest and lightest portions of the image; add smaller amount for dark pixels or larger amount for light pixels
luminace
small changes in brightness
chrominance
small differences in color
cookies
small files stored on the client computer by the server, and returned to the server with each page request
pixels
small points of colored light arranged in a grid to form a computer display (RGB)
white space
spaces that have been inserted for readability (exception: preformatted → <pre></pre>
image tag
specifies a file that contains an image;<img src="filename" alt="description"/>
logic operator
specifies a logical relationship between the words it connects (ex: the word AND)
singleton tags
tags that do not have a matching ending tag beginning with a /. It is replaced by /> (ex: horizontal rule <hr/>, break <br/>
ADC (analog to digital converter)
takes the continuous wave and samples it at regular intervals (ADC-CoDec-DAC
sampling rate
the faster the rate, the more accurately the wave is recorded
User Experience (UX)
the feeling a user has when interacting with a system → how easy it is to manipulate the application in general
anchor text
the highlighted link text, which is inside <a....> tags, describes the page it links to
protocol
the http:// part, which stands for Hypertext Transfer protocol → tells the computer how to handle the file → other ways to send via the File transfer protocol (FTP)
open source
the program code is publicly available and any programmer can contribute improvements to it (ex: firefox)
client/server structure
the protocol the internet uses → client refers to any situation where one computer gets services from another computer, the server
Asynchronous Communication
the sending and receiving occur at different times ex: post cards and text messages
redundancy
the use of multiple copies of info.
User Interface (UI)
the way a user interacts with a system and how this responds to such interaction (ex: colors, contrast, button interaction, touch feedback, hover on feedback)
descriptive text
title anchor text meta top-level heading tag alt attirbutes
compression
to change the representation in order to use fewer bits to store or transmit info.
analog to digital: sampling
to digitize continuous info, we must convert the data to bits; take measurements at regular intervals
hop
transition from one router to the next
binary system
two patters (PandA encoding has 2 patterns: present and absent)
list tags
unordered lists; ordered lists; definition lists
ordered lists
uses tags <ol> and </ol>, it replaces the bullets with numbers
meta
web page creators can add a <meta name="description" content="travel photos"/> tag in the head section which is a several sentence description of the page as in
World Wide Web
web servers (files and their services) do not confuse with the internet
authoritative sources
what experts say
payload
what's being sent
tags
words or abbreviations enclosed in angle brackets < and > Start tag and end tag; ex: <title></title>
tokens
words/search terms