Introduction to Computer Information Systems/Computer Networks and the Internet

The History of the Internet
The history of the internet begins in 1962 with J.C.R. Licklider’s memos about an Intergalactic Network idea, in which users around the world are connected and can access programs and data. With colleagues, he forms a research program called Information Processing Techniques Office (IPTO). After an experiment with an air travel reservation system, the first communication satellite is launched that can allow machines to exchange data. Soon, IBM introduces System 360 computers into the market which becomes remarkably popular. American Airlines debuts IBM’s SABRE air travel reservation system to process on-line transactions, which links over 50 cities through telephone lines (1964). By 1965 the first wide-area network connection is established by Larry Roberts and Thomas Marill. Over the next four years, the Network Working Group works diligently, creating a router, a modem, and even experimenting with monitors. On October 29, 1969 the first host-to-host connection was made! Then, over 3 years, memory, speed, processing, and communication capabilities are tested and refined and protocols are made. By 1973, 30 institutions are connected to the network called ARPANET. In 1977 Steve Jobs and Steve Wozniak announced the Apple II computer, opening the consumer and small business market for computers. This led to the creation of more modems for dial up services. A computer science research network called USENET sets up a server where newsgroups can post to, in 1979. A year later an email only service opens. Less than a decade later, 30,000 networks are on the internet due to the advances with computers, including the new Macintosh computer and the use of Ethernet. Within 2 years the number of hosts jumps to over 160,000! By 1991 over 600,000 hosts are connected in over 100 countries! In just 30 years the hypothetical concept J.C.R. Licklider once toyed with has become a part of everyday life! A lot of experimenting and funding went into the creation of this remarkable "cyberspace."

From ISP to URL
Now that you know the history of how the internet came to be, it's time to start exploring. You double-click your browser of choice, the screen opens up... and you start drawing blanks. 'Where do I go from here?' you might start asking yourself. Just take a deep breath; using the internet isn't as complicated as you might think. The most important thing to understand before you start browsing through the cornucopia of online resources is the URL, (Uniform Resource Locator.) The URL uniquely identifies a specific Web page. The URL is composed of a communication protocol, (typically HTTP or HTTPS,) a domain, and a page. If you want to have your own website, you have to buy the domain name and then build upon your address. The most interesting tidbit about domain names is that, just like fingerprints, no two can ever be the same. Unfortunately, this means you can't ever own the domain name www.apetit.com.

Internet Communication
In today's technologically booming society, there are hundreds of ways we are connected to computers and the Internet every day. We use computer networks (collections of computers and other devices that are connected together to enable users to share multiple forms of information) on a daily basis. While it is not always free to do so, such as having to pay an Internet service provider (ISP), there are many places that offer free wifi to people in their area. Today, we mostly use networks for social media, communication, and spreading of information. Think of the networks in your life. I'm guessing something like Facebook, Twitter, Instagram, or LinkedIn came to mind along with many others. These are all networks that allow us to share information whether it be personal, images, news stories, surveys, information on new products, etc., these networks have become engrained into our daily lives and most people see them as helpful devices for distance communication and spreading of ideas. Another way we use the Internet for communication is through email. Most people today have an email address because they are required for registration for many different things we use on a daily basis (such as the networks previously listed). Usernames for e-mails have to be unique to ensure that every person in the world that wants to be on the Internet can have e-mail. E-mails consist of a username (something to identify it specifically), followed by the @ symbol, and finally a domain name like “yahoo”, “gmail”, and many others. Many usernames just incorporate a person’s name, but you can also use periods, underscores, numbers and other symbols to make it unique. In the past, blank spaces were not allowed in a username but some companies do allow it now. One symbol that is still not allowed in a username is the @ symbol, because it could be confused with the same symbol that separates the username and domain name. An example of this is Drupal. It is each company’s responsibility to make sure that each username attached to their domain name is unique. Today's evolving technology is making it easier to access things like networks and email through all of the mobile devices available and the use of apps or condensed mobile versions of the full desktop websites. Besides the obvious social uses of e-mail communication, they are now being used to help college campuses communicate with their students to help alert the students of an emergency like a tornado, dangerous lightning storm, flood warning, or if an intruder is on the campus. All in all, the Internet and computer have changed our world in forms of communication.

Searching the Internet
Searching the internet for a specific page or phrase has become easier than ever through the help of online search engines. Certain webpages, most popularly Google, have specific programs and algorithms that sort through the vast expanse of information available on the web. These websites work by processing keywords that are typed into the search bar and displaying a large list of webpages matching the keywords. Even in the early days of the internet there were programs such as “Gopher” that could help search the net, although the scale of these searches has risen exponentially since then. Using special programs called “spiders”, the search engine compiles a list of results by crawling through the internet starting with the most popular websites and servers for the keywords searched. Through these processes an index is created by the spiders that is constantly being updated regarding the most popular and relevant results of all searches being completed, which on Google is over 3.5 billion per day and 1.2 trillion per year. The more that people use these search engines, the faster and more efficient they become. Other websites may search for more specific information on webpages such as phone numbers, addresses, and maps. The websites where this information is kept are called reference pages.

TCP/IP


TCP/IP - Transmission Control Protocol/Internet Protocol –the most prevalent protocol stack used to connect hosts to the network and networks to each other. The suite of communication protocols has been developed due the request of the Department of Defense as a protocol of an interconnection the experimental “ARPANET” and diverse computing networks. A great contribution to the development of TCP / IP stack has made by the University of Berkeley, implementing protocols stack in its version of OS UNIX which has led to widespread IP protocol. Moreover, the Internet, the biggest global information network, runs on TCP/IP suite and Internet Engineering Task Force (IETF) is a major contributor to the improvement of the standards of the stack, published in the form of specification RFC. Since the TCP / IP stack was designed before the OSI – Open System Interconnection, his 4 layered structure also corresponds to 7 layered OSI model is rather arbitrary. The lowest (level 4) corresponds to the physical and data link layer model OSI. This level in the TCP / IP protocols is not regulated, but it supports all popular standards of physical and data link layer both LAN (Ethernet, Token Ring, FDDI, Fast Ethernet, 100VG-AnyLAN0 and WAN - communication protocols, ("Point to Point" SLIP, PPP X.25, Frame Relay). The next level (level 3) - is the level of interconnection, which is engaged in the transmission of packets using a variety of transport technologies of local networks, regional networks, special communication lines, and so on. As the main network layer protocol (in terms of the model OSI) IP, which was originally designed to transmit packets through the many numbers of networks, combined both local and global protocols. Therefore, the IP protocol works well in networks with complex topologies using rationally presence of subsystems and economically consuming bandwidth low-speed communication lines. The IP protocol is a datagram protocol, which means it does not guarantee delivery of packets to the destination node, but trying to do it. Besides the IP protocol, internet layer is represented by some other protocols such as RIP (Routing Internet Protocol), OSPF (Open Shortest Path First) and ICMP (Internet Control Message Protocol). The last protocol is designed to share information about errors between routers and network node. Level 2 is called the primary. This level is a field of a functioning TCP (Transmission Control Protocol) and UDP (User Datagram Protocol). TCP provides the guaranteed delivering of the information and usually is being used by applications if data integrity and accuracy are critical. The UDP is being used for a non-guaranteed transmitting. The upper level 1 is the application level. Over the years, TCP / IP stack has accumulated a large number of protocols and application-level services. These include such widely used protocols as protocol to copy files FTP, TFTP, telnet, SMTP, HTTP, DNS and etc.