LEARN Networks

Welcome!

This page discusses the Fertile Questions for the Networks chapter of “How to Learn Computer Science”.

What drove the creation of the ARPANET (which later became the internet)?

US Universities began to buy computers in the 1960s to facilitate research. They were expensive machines, but time-sharing allowed them to be shared across campus. Better still would be to allow users at other institutions to log on, and this meant computer networks between cities. Hence the ARPANET was born.

In short, it allowed costly computers to be shared between researchers in different parts of the USA.

“It seems reasonable to envision, for a time 10 or 15 years hence, a ‘thinking center’ that will incorporate the functions of present-day libraries together with anticipated advances in information storage and retrieval … The picture readily enlarges itself into a network of such centers, connected to one another by wide-band communication lines and to individual users by leased-wire services. In such a system, the speed of the computers would be balanced, and the cost of the gigantic memories and the sophisticated programs would be divided by the number of users.”

Joseph Licklider, (1960) “Man-computer Symbiosis”, IRE Transactions on Human Factors in Electronics, HFE-1, 4-11, link.httcs.online/licklider

Are protocols unique to computer science?

Protocols are rules for communication, but they predate computers by millenia:

The word “protocol” comes from the Greek prōtókollon, which literally means “the first sheet glued on to a manuscript”. This sheet would describe the contents of the document, showing readers what was to come. The word came to English via French, where in the late 19th century it meant the ceremonial etiquette observed by the French head of state. 

“How to Learn Computer Science” page 180

Consider what we do when we meet new people, make conversation, buy something in a shop, move around school or a college campus, board an aeroplane. We follow protocol: an agreed (or assumed) set of rules of conduct. Can you think of other situations where you follow a protocol?

What key idea allowed the internet to expand rapidly?

TCP/IP. Bob Kahn and VInt Cerf’s idea of a protocol stack which allowed very different hardware devices to communicate with each other.

The day the ARPANET switched to Cerf and Kahn’s internet protocol stack, 1 January 1983, is widely regarded as the birthday of the internet. By 1987 there were 10,000 nodes, mostly technology giants, universities and military institutions. But at the end of the decade, the first commercial services arrived on the internet and the number of users exploded. In 1989, for the first time, home users could connect their computers to the internet through internet service providers (ISPs) like CompuServe and MCI.

From “How to Learn Computer Science” page 181

Is bad behaviour online a modern issue?

I’ve been on the internet since the 1980s, and I can say a resounding no!

Every September, students arriving at universities across North America would discover Usenet and be drilled in “netiquette”. In September 1993, however, an ISP called America Online (AOL) gave its many home subscribers access to Usenet. Users of AOL, CompuServe and many new cheap ISPs flooded Usenet, ignoring its “netiquette” social norms. A user called Dave Fischer, writing on alt.folklore.computers in January 1994, said: “September 1993 will go down in net history as the September that never ended.”

From “How to Learn Computer Science” page 182

“Trolling” (deliberately acting in bad faith, causing offence or seeking an argument) and “flaming” (verbal abuse, disrespect and threats) are as old as the internet, sadly. Make sure you know how to block and report!

What problem did Tim Berners-Lee try to solve by inventing the browser?

In 1980, Tim Berners-Lee was working at CERN in Geneva, Switzerland, where scientists were collaborating on thousands of scientific papers at any one time and organising them was a struggle. Research meant jumping around between documents stored on lots of different servers, retrieving them one at a time using file transfer protocol (FTP). Berners-Lee had an idea: what if he could just click a word to open another document?

He didn’t invent “hypertext”, that already existed but only worked within documents on the same server or LAN. Berners-Lee created HTML to formalise hypertext, and an application-layer protocol called HTTP to send it over the internet, and a browser to read HTML documents called Enquire, later renamed WorldWideWeb.

The big idea was HTML/HTTP and a browser that spoke those languages!

I hope you enjoyed this chapter. Please leave a review on Amazon. Thanks!