I was all prepared for this test (as you can see below) but got called home because my knucklehead child got in a fight at school.. sigh. I just hope that I remember all of this come test time (again!)
CSL 111 Study Sheet for Midterm
1.) Truth Tables
AND
(T and T is always T, F and F is always F, T and F and F and T is always F)
P
|
Q
| |
T
|
T
|
T
|
T
|
F
|
F
|
F
|
T
|
F
|
F
|
F
|
F
|
NAND (opposite AND) (N means NOT)
(T and T is always F, F and F is always T, T and F and F and T is always T)
P
|
Q
| |
T
|
T
|
F
|
T
|
F
|
T
|
F
|
T
|
T
|
F
|
F
|
T
|
OR
(T and T is always T, F and F is always F, T and F and F and T is always T)
P
|
Q
| |
T
|
T
|
T
|
T
|
F
|
T
|
F
|
T
|
T
|
F
|
F
|
F
|
NOR (opposite OR)
(T and T is always F, F and F is always T, T and F and F and T is always F)
P
|
Q
| |
T
|
T
|
F
|
T
|
F
|
F
|
F
|
T
|
F
|
F
|
F
|
T
|
XOR (X means exclusive)
(T and T is always F, F and F is always F, T and F and F and T is always T)
P
|
Q
| |
T
|
T
|
F
|
T
|
F
|
T
|
F
|
T
|
T
|
F
|
F
|
F
|
XNOR (opposite XOR)
(T and T is always T, F and F is always T, T and F and F and T is always F)
P
|
Q
| |
T
|
T
|
T
|
T
|
F
|
F
|
F
|
T
|
F
|
F
|
F
|
T
|
2.) Binary to Decimal and Decimal to Binary Conversions
Binary to Decimal (8 bits (columns) is a “byte”)-least “significance” number starting on right
128
|
64
|
32
|
16
|
8
|
4
|
2
|
1
|
1
|
0
|
0
|
1
|
1
|
0
|
1
|
0
|
128
|
0
|
0
|
16
|
8
|
0
|
2
|
0
|
Bottom row equals- 154
(154 is the decimal answer to the binary conversion of “10011010”)
*make up binary number
*Any column with a 1 gets the large number, any column with a 0 gets the 0
*FYI, usually a space in the middle btwn every 4 bits
Decimal to Binary Conversion
Decimal # we are converting is 154
128
|
64
|
32
|
16
|
8
|
4
|
2
|
1
|
1
|
0
|
0
|
1
|
1
|
0
|
1
|
0
|
26
|
10
|
2
|
0
|
*154 divides into 128 so 1 goes into first binary number (red)
*Subtract 154 from 128 and get 26
*26 can’t divide into 64, so it’s a 0, same with 32 it is also a 0
*26 CAN divide into 16, so it’s a 1 and 26-16=10, the next number
*10 CAN go into 8, so it get’s a 1, 10-8=2. 2 is the next number
*2 can not divide into 4, so it get’s a 0
*2 CAN divide into 2 so it get’s a 1, 2-2=0
*0 can not divide into 1, so it gets a 0
Binary Conversion Answer is 10011010
3.) Asynchronous and Synchronous Communications
Asynchronous- Information that is written at one time and read at another (sender to receiver)
-examples are post cards, text messages, emails, etc
Synchronous- both the sender and receiver are active at the same time
-examples are telephone, Skype, face to face conversations, etc
NOTE: The internet is fast enough to mimic synchronous communication due to it’s super fast speed
Examples of Asynch and Synch
Asynch
|
Movie
|
Synch
|
Chat session
|
Asynch
|
Email
|
Synch
|
Video conference
|
Asynch
|
Web page
|
Asynch
|
Book
|
Synch
|
Concert
|
Synch
|
Text Message (actively)
|
Asynch
|
Web Board (Forums)
|
Asynch
|
Blog
|
4.) Security and Privacy
Government- Because of things like 9/11, we have increased governmental surveillance of all of our communications (internet, phone, electronic banking, etc). This is due to the Patriot Act of 2001. This act allowed the government to essential snoop on everything we do. Edward Snowden who was an NSA contractor (worked for Booze Allen Hamilton contracting firm), whistleblew classified government documents that showed in detail what exactly the gov’t was looking at (things like social networking sites, google, etc etc). Americans were shocked that the government had it’s claws in every aspect of their lives but that is the world we live in now. With this information, the government can hold you accountable for acts of treason, terrorism, threat of national security, etc, etc. Basically everything you do online is looked at by the government. There is no longer any security or privacy where they are concerned so it is up to us as individuals to be very careful what we post online and who we communicate online with (even down to what sites we visit).
Businesses- Businesses are very good at figuring out what your buying preferences are and once you have bought from a certain business, these companies will keep track of your purchase information to send you more advertisements or even reminders that you are running out of your last order of cat medicine (for example), so it is time to order more. They spam your email and put you in telemarketing surveys/sales call rings in order to gain more business from you. Before 9/11 and the Patriot Act, the United States was part of the OECD (Organization for Economic Cooperation and Development-1980), which allowed for fair information practices in 34 countries and had an 8-point list of privacy principles that included: limited collection, security, use limitation, participation, and accountability to name a few. Basically, the business has to have your permission to do anything regarding your information. This does not happen in the US. When the EU adopted the OECD standards in 1995, they added that EU citizens be protected first and foremost, the US applied for this but was denied (Switzerland was accepted, a non EU country). Here in the US, we are more capitalistic than humanistic and corporations have the lay of the land as it were. Often times our information is sold to other companies for further invasion into our lives with the hope of us buying more and more of what they sell and what we do not need. We have a sectoral hit or miss privacy protection approach in the US, which means that things like our medical record information is protected by HIPAA but or social media information is not which is why you can go on amazon and buy shoes and find an advertisement for the same shoes you bought in your facebook feed.
-Opt in- to the change, allows the purpose to be changed (EU)
-Opt out- the purpose can be changed unless you disapprove to the new use (US)
5.) CSL Terms
State what the following acronyms stand for, and briefly explain each.
a. TCP/IP- Transmission Control Protocol/Internet Protocol- set of rules that allows computers to use data transmitted on the internet
b. LAN: Local Area network- group of computers physically near each other that are connected in a network.
c. WAN: Wide area network- can either be a larger LAN (say cover the size of a city) or reference the Internet as a whole
d. DSL: Digital subscriber line- internet connection that connects through traditional phone lines
e. WWW: World wide web- a world wide network that connects computers together
f. URL: Universal Resource Locator- web address
g. HTML: Hypertext Markup Language- the fundamental coding scheme that is used to encode web-pages
h. ISP: Internet Service Provider- company that provides internet to customers (there are many companies)
I. DNS: Domain Name System- Hierarchal structure we use to name computers replacing the IP addresses (ex 128.208.3.136). It translates domain names into IP Addresses, involving millions of computers making it decentralized (when machines fail, some of the internet is temporarily unavailable but the rest of it works)
The Four Components of a URL Web Address (ex. http://www.google.com)
http://: Hypertext Transfer Protocol- tells the computer how to handle the file
www.: World Wide Web- world wide network that connects computers together
Domain Name: (ex Google) It’s a part of identifying different web pages instead of using numbers (IP Addresses that are translated by DNS)
Top level Domain: (ex .com) Highest level of the hierarchical domain system
6.) Fragmentation-Postcard analogy by Vinton Cerf
Sending information over the internet is like sending your novel from Hawaii to your publisher in Maine using only postcards. Each numbered postcard (for correct sequencing) can take different routes, different post offices, different air/ground travel, different personal handling each card, but ultimately they all arrive at the same destination where they are put together. If anything is missing, the missing pieces can be recent.
