The kernel alone is not enough to use a computer. You also need a shell, commands such as ls and cp, and the programs that start when the computer starts. The kernel and these programs together are the operating system.
App Athe till program
App Ba web shop
App Ca report
Operating systemthe kernel + bash, ls, grep, init …
HardwareCPU, memory, disks, network
| Layer | What | Examples |
|---|---|---|
| Applications | The programs that do the work you want | The till program, a web shop |
| Operating system | The kernel and the base programs | Linux, bash, ls, /sbin/init |
| Hardware | The machine | CPU, memory, disks |
What the operating system gives
- A kernel that runs processes and controls the hardware.
- A shell and commands to use the computer.
- The directory layout and the settings files in
/etc. - The programs that start the background services, such as PID 1.
Applications use what the operating system gives. The till program does not need to know how to read a disk. It asks the operating system.
uname -o writes the name of the operating system:
text
learner@tidepool:~$ uname -o
GNU/LinuxGNU is the name of a large set of base programs, such as ls, cp and bash. Linux is the kernel. Together they make the operating system.