The Internet and the World Wide Web: Computer Science 0478 (Cambridge O Level / IGCSE)

A school's IT technician tells a new teacher: "If our broadband connection goes down, none of the school's web pages can be reached from here, but the pages themselves, and the servers that store them, are not affected; they are just unreachable from our building for now." The teacher replies, "So the pages themselves are what we call the internet, and the wires and routers that connect us to them are the World Wide Web?"

Which statement corrects the teacher's mistake?

A community library runs an online catalogue. Members use the exact web address "https://www.oakfield-library.org/catalogue/fiction.html" to browse the fiction section.

(a) Identify the part of this address that shows: (i) the protocol used to transfer the page [1] (ii) the domain name of the website [1] (iii) the name of the specific page being requested [1]

(b) State what it means for this address to use "https" rather than "http". [1]

(c) The library is about to add a page where members enter a password to renew their loans online. Explain why this new page should also use "https". [1]

A student at Brightwell Academy types "www.brightwell-academy.edu" into the address bar of a laptop that has never visited this website before, then presses enter.

(a) Describe, in the correct order, the steps that take place between the student pressing enter and the school's home page appearing on the screen. Your answer should refer to the domain name server (DNS), the IP address and the web server. [4]

(b) State one reason why computers communicate using IP addresses rather than domain names alone. [1]

(c) The student wants to be able to return to this website quickly tomorrow without retyping the full address. State one feature of the web browser itself that would let them do this. [1]

A customer browsing the online shop "Camptrail Outdoors" adds a tent and two camping chairs to their basket while looking through several pages of the site, then closes the web browser without buying anything. Two days later, they revisit the site on the same laptop: the basket is now empty, but the site greets them by name and has already selected their preferred tent size from before.

(a) State the type of cookie that would normally be used to keep the tent and chairs in the basket while the customer continued browsing during that first visit. [1]

(b) Explain why this type of cookie no longer has any effect once the customer returns two days later. [2]

(c) State the type of cookie responsible for the site remembering the customer's name and preferred tent size two days later. [1]

(d) Explain how this second type of cookie is able to do this across two separate visits, several days apart. [2]

(e) State one other function, used by websites generally, that this second type of cookie could also be used for at this shop. [1]

A privacy-conscious student changes the settings on their web browser so that it can no longer store any cookies at all, but every other browser feature is left switched on.

(a) State two functions of a web browser, other than storing cookies, that these settings would leave completely unaffected. [2]

(b) The student then browses the online shop "Foxglove Books", adding a novel to their basket and reading through three more pages before reaching the checkout, all within the same visit. Explain, with reference to session cookies, why the basket is now empty by the time they reach checkout, even though they never closed the browser tab. [3]

(c) The following week, the student visits Foxglove Books again on the same laptop. Explain why the site no longer displays a personalised welcome message using their name, even though it did so on previous visits before the cookie setting was changed. [2]

A student builds a small website for their school's chess club, hosted at "chessclub-brightfield.org". The website is made up of several separate pages: a home page, a "Fixtures" page and a "Members" page. On the home page, the words "Fixtures" and "Members" each appear underlined and in a different colour from the surrounding text. Clicking on either word opens the matching page.

(a) State the general term for the whole collection of related pages that make up the chess club's site (the home page, the Fixtures page and the Members page together). [1]

(b) State the general term for a single document within this site, such as the home page on its own. [1]

(c) The web server sends the browser a file written in HTML when the home page is requested. State what the browser does with this HTML file so that the student sees a formatted page, rather than the HTML code itself. [1]

(d) State the general term for the underlined, coloured word "Fixtures", which the student can click to open another page. [1]

(e) Describe what happens between the student's browser and the web server, from the moment the student clicks on "Fixtures" to the new page appearing on screen. [2]

The Ahmed family are moving into a new flat. Before anyone in the flat can use the internet, they sign a monthly contract with "Northgate Broadband", an internet service provider (ISP).

(a) State what is meant by the term "internet service provider (ISP)". [1]

(b) Identify two services, other than providing a connection to the internet, that an ISP such as Northgate Broadband might typically also provide to the family. [2]

(c) The family's laptop and router are both working correctly, but they cannot load any websites until the contract with Northgate Broadband is set up. Explain why a working laptop and router are not enough on their own. [2]

(d) State one factor, other than price, that the family could compare between different ISPs before choosing one. [1]

A student is reading a page about rainforests on the "GreenLeaf Nature" website, www.greenleafnature.org. Partway through the text, the words "Amazon Rainforest" are underlined, shown in a different colour from the rest of the text, and change the mouse pointer to a pointing hand; clicking them opens another page on the GreenLeaf Nature site itself. Elsewhere on the same page, a photograph of a toucan can also be clicked; doing so opens a page on a completely different website, www.birdwatch-global.com.

(a) State what is meant by a "hyperlink" on a web page. [1]

(b) Identify which of the two hyperlinks in this scenario, the "Amazon Rainforest" text or the toucan photograph, is an internal hyperlink and which is an external hyperlink. Justify your answer using the two web addresses given. [3]

(c) Explain one reason why it is useful for a reader to be able to tell, before clicking, whether a hyperlink is internal or external. [2]

Amir is on a video call using an app on his laptop, and the call is running smoothly with no problems. He then opens his web browser and types "ww.bramblecafe-orders.com" (missing a letter) into the address bar. The page fails to load, and the browser displays a "server not found" message.

What does this situation best indicate?

A student opens the website "HistoryHub" on a laptop for the first time, and the page's images take a few seconds to appear. Later that same day, they visit the exact same page again: this time, the same images appear almost instantly, even though the student has not saved any bookmarks and is not logged in to any account on the site.

(a) Name the web browser feature responsible for the images loading almost instantly on the second visit. [1]

(b) Explain how this feature is able to make the images load faster on the second visit. [2]

(c) Explain one way in which this feature is different from a cookie, even though both involve storing something on the student's own device. [2]

(d) State one circumstance under which this feature would no longer speed up loading the images on a later visit to HistoryHub. [1]