Exercises: Common operating systems

Match each device to the operating system it usually runs: (a) most desktop and laptop computers, (b) the iPhone, (c) most mobile phones from other brands, (d) Mac computers, (e) many servers and school devices. Systems: Windows, iOS, Android, macOS, GNU/Linux.

Which operating system does your home or classroom computer use? Describe it: name, what its desktop or home screen looks like and two applications you use on it. How is it similar to and different from your mobile phone's system?

Explain in your own words the difference between free/open-source software and proprietary software, and give an example of each type of program that you know or use.

Make a list of four real devices around you (your mobile phone, your home computer, a games console, a family member's phone...) and write down which operating system each one uses. Which one surprises you the most and why?

True or false? Justify each answer: (a) free software is always free of charge; (b) proprietary software can be copied and modified freely; (c) GNU/Linux is free/open-source software; (d) Windows is proprietary software.

Explain in your own words what a software licence is and reason why installing a program purchased for a single computer onto twenty computers could be illegal.

Which operating system is the most widely used on mobile phones? What about personal computers? Try to explain in your own words why each one dominates in its field (cost, applications, familiarity...).

GNU/Linux has a mascot, a penguin named Tux, and many people draw and share their own logos for the system. Reason why a system that does not belong to a company can have a mascot and symbols known all over the world.

The diagram shows two empty columns, one for free/open-source software and another for proprietary software, and six cards with programs and systems to classify, as shown in the diagram.

Place each card in the correct column and explain the criteria you used to decide. Then create a new card for each column.

Many local councils and public administrations use GNU/Linux on their computers. Compare Windows and GNU/Linux for use in a school, considering licence costs, who can study and improve the code, and available applications, and draw a conclusion.

Your family wants a photo editing program and is choosing between a free, open-source one and a paid, proprietary one. Compare both options according to three criteria: price, who can view and improve the code, and who decides on changes to the program. End by giving your reasoned recommendation.

In the technology classroom there are computers with Windows and others with GNU/Linux. Describe two differences you would notice when switching from one to the other (desktop appearance, way of installing applications, menus) and one thing you would do in exactly the same way on both, explaining why.

A video game company launches its new title exclusively for Windows. Analyse what reasons it might have (how many people use each system, how much it costs to port the game) and explain what options people using macOS or GNU/Linux have to play it.

If a free/open-source program is free of charge, who pays for the work to improve it? Explain two ways these projects sustain themselves (donations, companies selling technical support, volunteers) and give a real or reasonable example of each.

Compare installing an application from the official mobile app store with downloading it from any random website: what checks the app store carries out (security review, list of permissions) and what risks you run when bypassing those checks.

A designer states that he uses macOS 'because everyone in the industry uses it'. Analyse how group habits ('everyone uses X') influence the choice of systems and programs, what advantages and dangers that criterion has, and whether you would use it to choose your next computer.

The City Council of a municipality with 50 computers is considering migrating its entire system to open-source software. The Councillor for the Treasury states that the savings will be total and immediate because "open-source software costs nothing", but the head of IT warns that in the first year, the migration could cost more money than staying as they are. Justify why the technician is right by explaining two real indirect costs that the change will entail, and design a two-phase transition plan so that public services are not disrupted during staff adaptation.

The core of Android is open-source software, but many phones come with factory-installed proprietary applications that cannot be deleted. Analyse who truly controls the device in that case (the user, the manufacturer, the app company) and propose two things that, in your opinion, the person buying the phone should always be allowed to decide.

An NGO with no budget needs to set up ten old donated computers for a rural classroom: they need to write documents, browse the internet and use email. Choose the operating system and applications you would install (all free/open-source), calculate the total cost in licences and point out two limitations they might encounter and how you would solve them.

An autonomous community approves that all secondary schools use only open-source software in their classrooms. A group of families protests, claiming that their children "will be at an educational disadvantage compared to those who learn with commercial software from big tech companies". Refute this statement with two well-founded arguments regarding educational value and technological independence, and design two practical measures to help teachers and students adapt to the change without lowering the standard of the lessons.

A critical security vulnerability is discovered that affects both Android phones and iPhones. Apple sends out an update that reaches almost all of its devices within 24 hours; in contrast, on Android, most users take months to receive the patch from their manufacturer, and for many older models, it will never arrive. Justify why Android's open-source code and its "custom skins" cause this delay compared to Apple's closed system, and predict what risks a user assumes when buying a mobile phone from a brand that stops updating its operating system.

A programmer discovers a serious security flaw in a free/open-source program and in a proprietary program. Compare who can examine the flaw and who can fix it in each case, and reason what advantage (and what potential risk) open code has when it comes to security.

A secondary school has a budget of $2500\ \text{€}$ to set up a classroom with 25 new computers. If it installs commercial proprietary software, the licenses for the operating system, office suite, and image editing software would cost $130\ \text{€}$ per computer. Prove numerically whether the budget is sufficient to pay for these proprietary licenses and calculate how much money the school would save if it opts for a complete open-source software solution. In addition, design the package of open-source programs you would install and explain how you would solve the issue of students saving files in formats that are incompatible with their home computers.

An advertisement states: 'Our program is paid; that's why it is better than free ones.' Analyse whether the price guarantees the quality of a program: give two arguments in favour of the statement, two against, and finish with your reasoned conclusion, citing examples you know.