The free "PDF reader"
A user downloads a free PDF reader from a website they found in a search. The next day, pop-ups cover the screen and the browser opens odd pages.
Where you get a program, what watches the computer and what saves your files all matter. Three utilities answer that.
Key words
| Word | What it means | Example |
|---|---|---|
| Package manager | a utility that installs, updates and removes programs from a trusted list | |
| Dependency | another program that a program needs to run | |
| Malware | software made to harm a computer or steal data | a virus |
| Antivirus | a utility that scans for known malware | |
| Firewall | a utility that allows or blocks network traffic by rules | |
| Backup | a spare copy of data kept in case the original is lost | |
| Network | computers joined together so they can share things | |
| Repository | a trusted store of programs |
The cells students fill in are left blank in this preview.
By the end of this lesson
Note
I can describe what package managers, protection software and backup software do.
Starter
Have a go
Starter
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
A package manager installs software safely
A package manager installs, updates and removes programs from a repository, a trusted store. Examples are apt on Linux, winget on Windows and the app store on a phone.
It also fetches each dependency a program needs, and it can update everything with one command. A random download has none of these checks.
Extra: Count the installed packages
dpkg -l | wc -lA command for the lesson’s lab terminal. It is shown here and not run.
Extra: Read one package record
dpkg -s coreutils | head -3A command for the lesson’s lab terminal. It is shown here and not run.
Package manager or random download
| Feature | Package manager | Random download |
|---|---|---|
| Where from | A trusted repository | Any website |
| Dependencies | Fetched for you | You must find them |
| Updates | One command updates all | Each program separately, if at all |
| Removal | Clean and complete | May leave files behind |
The cells students fill in are left blank in this preview.
Protection software watches for danger
Antivirus scans files and compares them with a list of known malware. It must be updated often, or new malware gets through. A firewall watches network traffic. It follows rules, and blocks what the rules do not allow.
Neither is perfect. Antivirus misses brand-new malware. A firewall cannot stop a user from opening a bad file.