CSCI 101 Flashcards
1
Q
Hardware?
A
-computers are the physical embodiment of computation
2
Q
Software?
A
- embodies the programs that instruct computers in the steps needed to implement applications
- unrestricted by the physical world, can direct a computer to do almost anything
3
Q
“The experience?”
A
- -together, hardware and software present a virtual world that doesn’t exist, but which we experience
- these experiences, dictated by the interaction of the virtual and physical worlds, are new and important
4
Q
What is social media?
A
Cheap-anyone with access to the internet
Accessible- the tools are easy to use
Enabling- allows almost anyone to do things that previously were only the preserve of well-resourced organizations
5
Q
Problems with social media from the old era to the new reality?
A
- no control
- fewer gatekeepers
- fragmentation (people don’t just get info from a few centralized channels)
- new web landscape(now pull communications vs push)
- new journalism
6
Q
Software?
A
- is a collective term for programs
- programs are the instructions computers perform to implement apps
- it “instructs” the comp by providing the steps needed to perform task
- the comp follows the program and carries out the instructions
7
Q
The software stack?
A
- concept used to structure and organize the software in contemp comp systems
- series of layers of programs that implement user apps
- each software layer implements operations used to build the layers above
8
Q
Recorded tech?
A
- oldest form of info tech is recording a scene, performance, event, etc.
- digital copies are approx. of reality
- w/ todays tech, in most cases the approx, is extremely accurate
9
Q
New problems with artificial worlds?
A
- new privacy concerns
- spam
- scams
- online bullying/stalking
10
Q
Sourced content?
A
- is content produced for commercial purposes or to fulfill an info dissemination obligation
- content entirely controlled by the source organization or person
- the general public can’t add new info to sourced content
11
Q
Social content?
A
- refers to info created by visitors to the site
- users generate or contribute to the content of these sites
12
Q
Algorithm?
A
- is a precise, systematic method for producing a specified result
- programmers make algorithms perfectly precise for comps by writing them in a programming language
13
Q
What is a program?
A
-algorithms that have been specialized to a specific set of conditions and assumptions, and (usually) written in a specific programming language
14
Q
Abstract?
A
- many, but not all the details, of the story are irrelevant to the concept
- the abstraction has meaning beyond the story
15
Q
Operationally attuned?
A
-the ability to apply what we know about how a device or system works to simplify its use
16
Q
mnemonic?
A
-an aid for remembering something
AAH -Aubrie Ann Hagen
17
Q
Feedback?
A
an indication that either the comp is still working or is done
18
Q
“clicking around”
A
to explore the app to see what features are available
19
Q
“blazing away”
A
trying the app in a way you haven’t done so before
20
Q
Perfect reproduction?
A
- comps enode info as a sequence of binary digits, 0’s and 1’s
- because of the use of 2 digits, we call it digital info
- using only 0’s and 1’s means that digital info can be perfectly reproduced or replicated
21
Q
Exact duplicate?
A
- a second copy is made simply by duplicating the sequence of 0’s and 1’s
- this is one way digital improves an analog info
- analog info comes from or is store on a continuously variable medium
- a copy of an image, for example, could come out too dark or too light when compared to the original
22
Q
The perfect reproduction property of digital info?
A
it doesn’t matter where the copy came from
- both the original and the copy are the same sequence of 1’s and 0’s
- every copy can be made from the last copy, and still be identical to the original
23
Q
Metaphor?
A
an icon or image used as representative or symbolic of a computation
24
Q
Why is touch a metaphor?
A
it changes how humans interact with the comp.
-hands “on” with the content
25
Synchronous Communication?
both the sender and the receiver are active at the same time (talking on the phone)
26
Asynchronous communication?
the sending and receiving occur at different times (email)
27
Broadcast communication?
single sender and many receivers
28
multicast?
many receivers, but usually a specific group (specialized topics)
29
Point-to-point communication?
one specific sender and one specific receiver (telephone)
30
What is the internet's communications properties?
- internet supports point-to-point asynchronous communication
- internet provides a general communication "fabric" linking all comps connected to it
- comps and the network become a single medium
31
Client/server structure?
Your comp is the client comp and the comp with the web page is the server. the relationship is a very brief relationship, lasting from the moment the request is sent to the moment the service is received
32
Getting more connected with the internet?
- client software "slices up" the signals coming from the comps microphone and video camera into packet-size blocks
- content is transferred to the other party, whose client reassembles the sound and image for display
- process relies on a fast and reliable transmission to make it seem like a direct connection
33
IP address?
- each comp connected to the internet is given this unique address
- a series of four numbers separated by dots
- range of each of these numbers (0-255)
34
Domain names?
domain= related group of networked comps
example: spiff.cs.washington.edu
- name of comp= spiff
- which is part of the comp science and engineering dept domain (cs)
- which is part of the UW domain (washington)
- which is part of the edu domain (edu)
35
Domain Name system?
DNS-translates the hierarchical, human-readable names into the four number IP address
-every internet host knows the IP address of its nearest DNS name server
36
TLD's
Top-level domain
- .edu
- .com
- .org
- .net
- .mil
- .gov
37
TCP/IP postcard analogy?
- internet is like sending a novel in postcards
- novel broken into small units on postcards
- post cards are numbered then mailed
- receiver gets notecards but not necessarily in order
- then they are arranged in order
38
Ip packets?
hold one unit of information, the destination IP, and their sequence number (what packet they are)
-each packet is independent
39
WAN?
- wide area networks (the internet is a collection of these)
- these are networks that are not geographically close
- internet is a collection of point-to-point channels
- packets must visit a sequence of comps (or hops) before they reach their destination
40
LAN?
- local area network where comps are geographically close
- usually they can be linked by a single cable or pair of wires
- ethernet is the main tech for local area networks
41
Ethernet?
- physical setup-wire, wire pair, optical fiber, called the channel
- engineers "tap" into the channel to connect a comp
- it allows it to send a signal or an electronic pulse or light flash onto the channel
- all comps, including the sender, cant detect the signal
42
Connections by ISP?
- internet service provider
- comps that sell connection to the internet
- comp places modem at house
- modems convert the bits a comp outputs into a form that is compatible with the carrier
43
Wireless networks?
- variation of a LAN connection
- router is:
- physically connected to an ISP's modem
- connected to the internet
- capable of broadcasting and receiving signals
44
Requesting a web page? URL?
3 main parts
- protocol=tells the comps how to handle the file (http)
- server comps name(www.wwu.edu)
- page's pathname=tells the server which file(page) is requested and where to find it (decks/2284..)
45
2 advantages to storing and seeing the source rather than the image itself?
- a description file usually requires less info
| - the browser can adapt the source image to your comp more easily
46
Directory hierarchy?
- like a tree, folders are the branch points, files are the leaves
- Down in the hierarchy means into subfolders
- up in the hierarchy means into folders
47
File structure?
a / means we move into a subfolder or to the file, we go down the hierarchy
48
Web pages?
- are created, stored and sent in encoded form
- a browser converts them to what we see on the screen
- hypertext markup anguage (HTML) is the main language used to define how a web page should look
49
XHTML?
extensible hypertext markup language
| -tags MUST be lowercase
50
Singleton tags?
tags that don't have a matching ending tag
51
Required tags?
- head(like the title)
- body
- html to enclose those two
52
Firefox?
- a free open source browser
| - open source means that the program code is publicly available, and any programmer can contribute improvements to it
53
URL made from?
- a protocol specification (http)
- a domain or IP address (www.bioz.com)
- a path to the file (/bios/sci/russell.html)
54
relative pathnames?
describes how to find the referenced file relative to the file in which the anchor tag appears
55
How to go "higher" in a hierarchy?
add ../ to the beginning of the href attribute
56
Structure of the image tag?
57
GIF?
graphics interchange format- nest suited for cartoons and simple drawings
58
JPEG?
joint photographic experts group-appropriate for high resolution photographs and complex artwork
59
Attributes?
- an additional specification included inside a tag
- the abb. href, src, and alt are attributes
- attributes have the form name="value"
60
CSS
cascading style sheets-are responsible for much of the design of web pages
-it is a general styling system for documents that simplifies the task of creating complex page designs
61
Adding class to style?
- a class is a family of styling specifications with a common name.
- the class is given in 2 places
1. in the style definition inside the style tags in the
2. at the site in the HTML code when the code is used
62
5 levels of styling info?
1. default, given by browser settings
2. external, given in a file
3. global, given in the section
4. range, given in an enclosing tag
5. site, given by the style attribute
63
Pseudo classes?
- link: the style for an unvisited link
- hover: the style for when the cursor hovers over a link
- visited: the style for links that have been visited
64
How a search engine works? Step 1.
-crawling, visits every web page that it can find
- web pages are found by:
-the crawler has a to do list that is loaded with a set of pages to start
-when a URL is found while crawling a page, it adds that URL to the to do list
>the main work of the crawler is to build an index
65
How a search engine works? Token?
- the index is a list of tokens (or words) that are associated with the page
- the token might be part of the page's title
- there are other ways for a token to be associated with a page
- for each token, the crawler creates a list of the URLs associated with that token
66
How a search engine works? step 2.
- query processing
- the user persons tokens to the query processor
- the search engine then looks up the word in the index and returns to you a hit list
- by creating the index ahead of time, search engines are able to answer user queries very quickly
67
Intersecting queries?
- for multiple words, the query processor fetches the index lists for each of the terms
- URLs that are in all of the lists are looked at and compared
- the query processor intersects the lists
- the URL lists are alphabetized to speed up the processing…it is easier to notice when the same URL is on multiple lists
68
Rules for intersecting alphabetized lists
1. put a marker (arrow) at the start of each token's index list
2. if all markers point to the same URL, save it, because all tokens are associated with the page
3. move the marker(s) to the next position for whichever UrL is earliest in the alphabet
4. repeat steps 2-3 until some marker reaches the end of the list
69
Power of an indexed search?
the comp:
- takes the time to crawl the data
- build an index first
- find the index entries for each word
- intersect the lists to find the info for an AND-query
70
What does it mean when there is a "hit"?
the search term is associated with the page. this doesn't mean the word is on the page
71
Descriptive text: title?
the encloses a short phrase describing the whole page
72
Descriptive text: anchor text?
the highlighted link text, inside tags, describes the page it links to
73
Descriptive text: meta?
a tag in the head section can hold a several sentence description of the page
74
Descriptive text: alt?
alt attributes- the tag has an alt attribute that gives a textual description
75
Collating sequence?
placing info in order by using non-digit symbols, you need to agree on an ordering for the basic symbols
76
PandA representation?
the name used for two fundamental patterns of digital info.
- presence
- absence
77
Discrete?
means distinct or separable. it is not possible to transform one value into another by tiny gradations
78
Bit?
a contraction for binary digit. bit sequences can be interpreted as binary numbers. groups of bits form symbols
79
Hexadecimal digits?
```
16 digits.
-0-9, a, b, c, d, e, f
0000=hex 0
0001= hex 1
1111= hex F
```
80
Binary numbers vx digital numbers?
```
binary=0 and 1
-1010 (base 10)
(0x1) +(1x10)+(0x100)+(1x1000)
digital=0-9
1, 2, 4, 8, 16, ...
```
81
Digitizing text?
- the number of bits determines the number of symbols available for representing values:
- n bits in sequence yield 2n symbols
- the more characters you want encoded, the more symbols you need
82
Assigning symbols?
- to represent 95 distinct symbols, we need 7 bits
- 6 bits gives only 2^6= 64 symbols
- 7 bits give 2^7= 128 symbols
83
ASCII
-American Standard Code for Info Interchange
-ascii is a widely used 7-bit code
The advantages of a "standard" are many:
-comp parts built by different manufacturers can be connected
-programs can create data and store it so that other programs can process it later, and so forth
84
Byte?
- extended ASCII: an 8 bit code which IBM gave the name of byte
- it is a standard unit for comp memory
