By the time you finished Setting Up Python, you had already met the two layers this page names: the app you installed, and the operating system you installed it into. Every device works this way — a stack, with your apps on top and one very busy program underneath.
Apps do one job
An app — short for application — is software with a purpose you can say in a sentence. Browse the web. Edit photos. Play music. Run Python. Apps are the layer you choose: each one is on your device because somebody decided to put it there, and each can be removed without the device caring.
The operating system does everything else
The OS — Windows, macOS, iOS, Android, Linux — is the program that runs the machine itself. It decides which app gets the CPU next, parcels out memory, draws the windows, reads the keyboard, and guards the files. Apps never touch the hardware from Hardware Inside the Box directly — they ask the OS, and the OS does the touching. That is also why the “same” app on your phone and your laptop is really two apps: each was written to ask a different OS.
File systems and storage organisation
The operating system manages how data is saved to physical and cloud storage. It structures files into hierarchical folders (directories), tracks file paths, and enforces access permissions. Good file management habits — structuring directories by project, maintaining backups, and knowing whether a file lives locally or in cloud sync — are covered in Files and the Cloud.
Researching software and assessing requirements
Before adopting new software tools or recommending programs to a client (as in The Device Recommendation), systematic research is required:
- System and hardware compatibility — verify whether the software supports the user’s OS version, processor architecture, and available RAM.
- Consulting authoritative documentation — review official release notes, developer guides, and help documentation (as taught in Finding Answers Online) rather than relying on unverified forum opinions.
- Licensing, privacy, and support — evaluate whether open-source or commercial tools best suit the user’s budget and security needs.
Updates are maintenance, not nagging
All software ships with mistakes in it — all of it, always, which is why Debugging Is the Job is a discussion and not a joke. Updates are how mistakes get fixed after shipping, and some of those mistakes are security holes that Staying Secure Online would rather you not leave open.
The unglamorous truth about updates
An update notification is a repair crew offering to fix your house for free. Scheduling it for a convenient hour is sensible — overnight is fine. Postponing it forever mostly protects the bugs.
Curriculum connection
B1.3
describe the functions of various types of software they encounter in their everyday life
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B2.1
use file management techniques, including those related to local and cloud storage, to organize, edit, and share files
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B2.2
identify and use effective research practices and supports when learning to use new hardware or software
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B2.3
assess the hardware and software requirements for various users, contexts, and purposes in order to make recommendations for devices and programs
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