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Complete list of Terms and Definitions for Internet

Terms Definitions
BPS=??? BPS=baud[log2(Levels)]
2005 YouTube is lanuched
Internet Countless networks of computers connected together across the world, allowing millions of people to share information
scrutiny surveillance; close and continuous watching or guarding.
Server A computer that stores information, such as a Web page, that can be accessed by another computer
interoptability the ability of all brands,modles,and makes of computers to communicate with each other
directories review and cataloguing services that group Web sites under particular categories (e.g Arts & Humanities, News & Media, Entertainment)
breakdown an analysis or classification of something; division into parts, categories, processes, etc.
hardware the physical machinery of the computer, monitor, keyboard, mouse, printer, etc
Cookies Electronic text files that web servers store on the hard drive of a user's computer. These files can be accessed later by the original server or another
Douglas Englebert Pictured a user-friendly tool that average people could use, obtaining information, but he never thought computers would think for humans.
firewall a form of protection from unauthorized access: a method to keep network secure
What is Nyquist's theorem? sampling rate=2 * fmax
html HyperText Markup Language: a set of standards, a variety of SGML, used to tag the elements of a hypertext document. It is the standard protocol for formatting and displaying documents on the World Wide Web.
intellectual property materials protected by copyright laws, including songs, movies, books, etc.
HTTP protocal used on the web that defines how pages are transmitted
What's an API? Application Program Interface. The API we need to know about is the socket API.
Describe half duplex transmission. Half duplex transmission allows transmission both ways, but not at the same time. Only one side can have the talking stick at a time, like in a walkie talkie.
Define frequency. The number of ocillations per unit time (usually seconds).
burst to break, break open, or fly apart with sudden violence:
predator one who stalks or uses lies, secrecy, or stealth to get close enough to another person in order to easily hurt or harm them
search query the act of conducting a keyword search using a search engine
Internet service provider (ISP) a company that provides internet access to homes and businesses for a fee
What's differential manchester encoding? Like manchester encoding, but relies on relative transitions, rather than absolute ones.
WTF is Internetworking? A set of standards to interconnect many packet switching technologies, ultimately it would become TCP/IP.
Define amplitude. The difference between the max and min signal height.
queue a file or line, esp. of people waiting their turn.
What is a decibel? It's the measure of the difference between two power levels.
What's narrowband? Up to 128 kbps. These are dialup, leased circuit using modem, fractional t1 circuit, ISDN.
Describe the network interface layer of TCP/IP (layer 2). These protocols specify communication between higher layers of protocols, usually implemented in software and the underlying network, which is implemented in hardware. These specs include network addresses, max packet size, hardware addressing.
What does a transmitter do? A transmitter encodes digital data into digital signals using manchester, differential manchester, or other line coding.
What are the characteristics of FTP? Arbitrary file contents, bidirectional transfer, support for authentication and ownership, ability to browse folders, textrual control messages, accomodates heterogeneity.
What is a communication protocol? A communication protocol specifies the details for one aspect of a computer communication, including actions to be taken when errors or unexpected situations arise. A given protocol may specify details such as voltage and signals or high level things suc
i-MENTORs club an area on the i-SAFE Web site where i-MENTORs exchange ideas, chat with other i-MENTORs, and learn Internet safety information to provide to their schools and communities
What does a client side socket call look like? socket, connect, send/receive, close
Why are sine waves even important? Because many natural phenomena produce a signal tha corresponds to a sine wave as a function of time.
What are the four major HTTP request types? GET, HEAD, POST, PUT
What are the two aspects of interaction specified by application layer protocols? Data representation and data transfer.
A communications channel is classified as one of three types. What are those types? Simplex, Full duplex, and Half duplex.
What are the characteristics of HTTP? Uses text control messages, transfers binary data files, can download or upload data, incorporates caching
What does the HTTP request HEAD do? Requests status information, server responds by sending status info, but NOT a copy of the doc.
Contrast analog and digital signals. An analog signal is a continuous mathematical function. A digital signal has a fixed set of valid levels.
What are the properties of the Stream Paradigm? Connection oriented, 1-1 communication, sequence of individual bytes, arbitrary length transfer, used by most apps, build on TCP
What are the four steps of PCM? Low Pass Filtering --> Sampling -->Quantization -->Encoding
What do we mean by synchronization error? When two things communicate, the receiver has to read all the data correctly, so it needs to start reading at the same moment the sender sends things and stop when the sender is done. It can't be early or late.
What does a server side socket call look like? socket, bind, listen, accept, send/receive, close.
What does the HTTP request GET do? Requests a document, server responds with status and a copy of the doc.
What is manchester encoding? It's a standard for line coding. It's used with Ethernet. It uses transition, rather than levels, to define bits. A 1 corresponds to a transition from 0 to positive. A zero corresponds to a transition from positive to 0.
How does the hardware implementation of CRC go? CRC hardware is a shift register with xor gates between some of the bits. The shift register operates once per bit and xors some of them and when the whole input has been shifted into the register, the value in the register is the CRC.
What are the advantages and disadvantages of a geostationary earth orbit satellite? It remains at a fixed position with respect to a location on the earth's surface, but it's farther away.
What is a composite signal? It's a signal that can be broken down into simple waves.
What is a private network? A network is private if use of the network is restricted to one group. (May include circuits leased from a provider.)
Describe the application layer of TCP/IP (Layer 5) These protocols describe how a pair of applications interact when they communicate, including format and meaning of messages as well as procedures to be followed. Specifications for email, file transfer, web browsing, phone and video teleconferences belo
What are the conceptual pieces of a data communications system? Preparing information from the source to transmit, transmitting across a physical medium, extracting information from the source and delivering it.
What does a constellation diagram show? The assignment of data bits to phase changes.
What is a low pass filter? A low-pass filter is a filter that passes low-frequency signals but attenuates (reduces the amplitude of) signals with frequencies higher than the cutoff frequency. The actual amount of attenuation for each frequency varies from filter to filter.
When does the transition occur in manchester encoding? In the middle of the time slot allocated to a bit. This allows the signal to return to the previous level in case the data contains two repeated 0s or 1s.
What does the HTTP request POST do? Sends data to a server, the server appends the data to a specified item (eg a message is appended to a list).
How does modulation with two inputs work? There's a signal and there's a carrier and the two combine to create a modulated carrier. So, the output carrier has been altered by the information.
What is the orbit of a medium earth orbit satellite and what is it used for? Elliptical, primarily used to provide communication at the poles.
What are the media that go with light energy? Optical fiber, IR, Laser. That's right, frickin' laser beams.
What's the big idea behind a browser cache? A browser can reduce download times by saving a copy of each image in a cache on the user's disk and using the cached copy.
What is the advantage of phase shift keying? The ability to represent more than one data bit at a given change.
How has the data being sent across the internet evolved? text to graphics to video clips to full motion video
What's the problem with Single Parity Checking? It's very weak. If you flip an even number of bits in error, single parity checking won't catch it.
What is the lifetime of a socket in a concurrent server? The original socket used to accept connections exists so long as the main server thread executes. a socket used for a specific connection exists only so long as the thread exists to handle that connection.
What about row and column parity? How does it work? When you add up the parity both down and across, you can zero in on the problematic bit, which can be corrected if there's only one of them. This will also catch errors in which two or three bits have changed, even if it can't correct them, opening the way to ask for re-sending.
If the maximum frequency audible to a human ear is 20kHz, at what rate must the analog signal from a mic be sampled in converting to digital? sampling rate= 2 * fmax. Our fmax is 20khz. 2*20k=40k. So sample 40,000 times per second.