What an operating system is for

Explain in your own words what the operating system of a device is and write down the name of the operating system of your mobile phone or computer, along with two things that this system allows you to do.

The diagram shows the layers of a computer, from the person using it to the machine, but an intermediate layer is covered with a question mark, as shown in the diagram.

Which layer is missing from the diagram? Explain what that layer does and reason why applications do not communicate directly with the hardware.

When you drag a file to the recycle bin (or trash), who actually moves it: you, the open application or the operating system? Reason your answer thinking about who controls the device's folders.

The operating system works without you noticing. Name three tasks it performs for you in the background (managing memory, displaying battery alerts, keeping time, controlling who logs into the device...) and explain one of them in a single sentence.

You can listen to music while typing a document with your web browser open. Explain in your own words how the operating system manages to make all applications share the CPU and memory without 'clashing', and what you notice when you open too many at once.

Your phone displays the alert 'background applications have been closed' when you open many at once. Relate this alert to the RAM management carried out by the operating system and explain why the music app is usually the last one to be closed.

Explain the difference between shutting down ('apagar') and sleeping ('suspender') a computer: what the operating system does with your open documents in each case and when it is best to use each option.

When you plug in a USB flash drive, the computer recognises it almost instantly and displays its icon. Explain what the operating system does in those few seconds (detecting the device, loading its driver, displaying it to the user) and why you do not need to install anything manually.

The operating system organises files into folders. Your 'Documents' folder is a mess of schoolwork, photos and downloads. Design a folder structure to organise everything for the school year, write down the rules you followed (clear names, subfolders by subject...) and explain what advantages it will have by June.

The system asks for a password to install a new program, but not to open a text document. Reason why the operating system protects some actions and not others, and explain what could happen if installing programs did not require any permissions.

A high school student downloads a game installer and another for a free 3D design program. When trying to run them from their student account, in both cases the operating system asks for the administrator password and blocks the installation. The student protests: «The operating system should allow installing the design software because it is educational and only block the games».

1. a) Technically refute the student's argument: explain why an operating system cannot distinguish by itself whether a file is 'educational' or 'entertainment' based on the permissions system.
2. b) Design a technical or configuration solution for the classroom that allows students to test necessary software tools for class without granting them full administrator permissions on the computers.

Analyze these two incidents that occurred on a user's mobile phone:

• Incident A: While playing a game, the game screen suddenly closed and returned to the phone's home menu; the rest of the applications and calls continued to work normally.

• Incident B: The screen froze completely, the physical buttons did not respond, and after several seconds of a black screen, the phone restarted completely.

1. a) Using the layer model (Hardware, Operating System, Applications, User), diagnose at which level the fault originated in each incident and justify why in Incident B all functions stopped simultaneously.
2. b) Predict what consequences it would have for device stability if applications could communicate directly with memory and the processor without operating system supervision.