history of the internet and networks the start of our digital world!
TRANSCRIPT
History of the Internet and Networks
The start of our digital world!
The Internet’s Origin
• The ideas behind the internet started back in the 1850’s and 1860’s with the idea of a Trans-Atlantic Telegraph Cable.
• This technology could allow 2 nations, separated by an ocean much faster communication that would otherwise be available.
Issues at Sea
• The first cables that were laid across the ocean floor in 1858 were made of generic materials that may have been substandard and failed within weeks.
• Later cables from 1866 made of more quality materials lasted longer, but issues arose about how best to send and receive signals.
Atlantic Cables
• The cables that were used in the successful 1866 trials could only send 8 words each minute.
• This second cable was a vast improvement over the original 1858 cables that took over 16 hours to send a message of 98 words.
• It wasn’t until the 20th century that the Transatlantic Cable could send more than 100 words each minute.
Trans-Atlantic Cable
The transatlantic cable was composed of several layers of cables and insulators to keep the signal from degrading to the point where it could no longer be read or understood.
Morse Code.• Technological innovations created to solve the
problems from those days are still a driving force in solving todays issues.
• Morse code was one of the methods used to transmit data on those long land/water cables.
• This “code” system was invented in the 1830’s and used throughout the America’s and later in Europe. It is still used today.
Morse Code• Morse code is a method of transmitting
text/word information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment.
• For example the international signal for distress is “SOS” which looks like:
The Beginning of Morse Code
• In 1836, the American artist/inventor Samuel F. B. Morse, the American physicist Joseph Henry, and Alfred Vail developed an electrical telegraph system.
• This system sent pulses of electric current along wires which controlled an electromagnet that was located at the receiving end of the telegraph system.
Transmission
• A code was needed to transmit using only a few wires or one type of signal medium.
• What these inventors came up with was a code that used pulses, and the silence between them to transmit the text.
• Every letter was given a set number of Dots and Dashes.
Dots and Dashes.
• Dots represented one press or interruption of the sending device. Dot = 1 time unit
• A dash on the other hand is made when the press or instruction is lengthened to three times that of a dot. Dash = 3 time units.
Example of Morse Code chart
Understanding Morse
• For our purposes when you write Morse code place a vertical “|” line between letters.
• For example, the word rat has three letters, if you wrote this in Morse Code it would look like:
RAT = R A T
| ● – ● | ● – | – |
Morse Code
• When Morse Code was more widely used, it was required that the operators be able to send and decode around 16-20 words each minute.
• This means that sending a long document could take a very long time. For example during the world wars how fast your operator could send your message could mean the difference in life or death.
Transmission DevicesIn a straight key transmission devices, the signal is "on" when the knob is pressed, and "off" when it is released. Length and timing of the dots and dashes are entirely controlled by the operator
Morse Code, old news.
• While the usage of Morse code has decreased in recent years thanks to the digital revolution, it laid the fundamentals of what long distance information sharing is all about.
Next Big Thing!
• The next technological milestone that helped bring about the Internet as we know it was due in large part to the Soviet Union.
• In October 1957, during the Cold War, the Soviets stunned the world by launching into a low earth orbit the first manmade space satellite, Sputnik 1
Soviet Union
• Sputnik 1 was a roundmetal sphere that orbitedaround the earth pulsingradio waves.
• This satellite was seen byeveryone and its radiopulses could be picked upby most receivers.
There goes the Neighborhood!
• This scared the US, since we were locked in a ideological, economic, and technological cold war with the Soviets and they seemed to be doing better than we were.
• In response the current US president Dwight D. Eisenhower created a governmental division called the “Advanced Research Projects Agency” or ARPA for short.
ARPA or DARPA
• ARPA was created as a “Think-Tank” to research and develop projects to expand the frontiers of US technology and science.
• The goal, ultimately was to ensure U.S. military technology be more sophisticated than that of the nation's potential enemies, meaning the Soviets and other communist nations.
• Later on ARPA was renamed DARPA to denote the Defense aspect of their work, The D is for Defense
1+2+3+? = Internet?
• We have a Think-Tank at DARPA but nothing really solid to focus on or think about, no real concepts to discuss yet
• The concepts that were to become the foundation of the internet was thought up in a series of memos and papers by J.C.R. Licklider at the Massachusetts Institute of Technology (MIT)
J.C.R. Licklider
• In an August 1962 paper discussing his "Galactic Network" concept, He envisioned a globally interconnected set of computers through which everyone could quickly access data and programs from any site.
• This was revolutionary!
Time at DARPA • Licklider was the first head of the computer
research program at DARPA, where they worked to beat the Soviets during the month of October 1962
• During this time he many others of his coworkers and fellow academics of the massive importance of these networking concepts.
DARPA, Licklider Concepts and…..
• There was a catch to all these networking concepts. There was no reliable way to send data efficiently to each of the computers that were connected to the same network.
• Not just that, all these networks couldn’t really talk to each other, this issue would plague networks for years to come.
Room of computers.
• If you went to talk to the technology department at MIT you would use one network, to talk to a different university, you would have to use a different network and so on.
• A network user would literally have 4 or 5 computers they would have to switch between.
Packets• Leonard Kleinrock at MIT started working on a
concept, this concept was called Packet Switching.
• This theory basically set up how we use the internet today, instead of a direct 1 to 1 connection like a telephone
• Using the Theory, networks would instead broadcast many parts, or packets of the information, this allows the network to be used by others for other reasons simultaneously.
One at a time…
• Network use could be shared since mixing packets was fine due to a system to reorder them
• Imagine that you could only look up one webpage at a time, regardless of how many computers you had connected.
• That is how networks were before packets and packet switching.
Packets 2• Thanks to packets, information could be sent
between computers on the same network in a much more seamless and speedy way.
• With data being broken into sections or packets, data transmission speeds were increased to 25x their original speed.
• The receiving computer would take the packets of information then reorder them for use.
Networks.• With the advances in packets and the increasing
amount of computers, many different networks sprang up.
• Some connecting colleges and universities others to connect Government and military installations.
• Each network consisted of several computers, each transmitting data back and forth, but only to other computers in their unique small network.
Alone in a crowd.
• During this timeframe in the 1970’s, the networks being used like ARPANET, National Science Foundation’s NSFNET networks, and various other academic and military networks found a need to come together and share resources.
• What these networks needed was a way to communicate with each other.
“Do you understand the words that are coming out of my mouth?”
• The last major issue that was holding back the early networks revolved around computer language, how the computer handled data.
• Each small group of connected computers talked to each other in their own unique language. Other groups used a different unique language. If you tried to get different groups together, it was chaos and no one could understand each other.
Easy Language Example
• Imagine you and 4 of your close friends trying to explain what Ice-cream tasted like to 5 people from Russia who spoke only Russian.
• Then have those 5 Russians take what you told them, then retell it to 5 Chinese people.
• Without a common language it wouldn’t work.
TCP/IP
• TCP/IP stands for Transmission Control Protocol (TCP) and Internet Protocol (IP)
• This was the standard that told all the computers on a network what to do.
• It dealt with how data should be formatted, addressed, transmitted, routed and received at the destination
Not for everyone.
• Thanks to TCP/IP many of these scientific and military networks gained the ability to talk to one another. It formed a base language.
• Due to their nature as academic and military networks, they had certain restrictions as to what content could be supplied and accessed.
Restrictions
• Some restrictions would include: – Information for academic use only– Military records• Private Records• General records
– College library data on available resources– Government data like Census information
Beginning of a new age.
• The ARPANET was decommissioned in 1990. Thus removing any restrictions they placed on the flow of data
• The NSFNET network was decommissioned in 1995. Likewise removing restrictions on data.
• With the last academic/military networks offline, the Internet was free to be commercialized for business and leisure.
ISPs
• Commercial Internet service providers (ISPs) began to emerge in the 1990’s to assist regular users to “Log on” to the internet.
• Internet usage in those days were limited due to limited numbers of home computers.
Friends with Benefits
• In those days it was rare to have more than 2 or 3 friends that had access to a computer.
• Even more rare if they had a Telephone Dialup modem that could connect to the internet.
Speeds.
• Dial up speeds were very slow by todays standards.
• Once you connected a computer to the internet, you couldn’t use the phone or connect other computers.
• Downloading a standard 3 minute song on Dialup would take around 15 minutes. Today that same song would take less than 15 seconds.
Its your Turn to tell me.
• Work in Pairs or solo• Research the History Of The Internet• Type your history in Microsoft Word• Must be at least 1 page, no more than 2. • You MUST tell me where you get your
information. – “From the website… or According to….”