UNIX, the origin of AT & T's Bell Labs Linux, was born. Since UNIX distributed the source code, many users were free to modify it. However, as many UNIXes were created and disorganized, AT & T signed a license agreement and began managing UNIX.
Many UNIXes had to pay a high license fee. Meanwhile, in 1991 Linus Torvalds developed Linux, an operating system very similar to UNIX. Linux was distributed as a free software license and has been developed and used by many users.
The OS can be divided into two areas, "kernel" and "userland".
It is the core system of the OS and is responsible for the core functions of directly interacting with the hardware. The kernel is responsible for absorbing hardware differences and allowing programs to run on any hardware. Hardware refers to keyboards, mice, communication lines, etc., and a program called a device driver has the role of absorbing the differences between each hardware.
It refers to software other than the kernel in the OS, such as the file system, file operation commands, and shell. Linux can be operated with commands and runs on userland.
Linux provides an interactive command input environment called the shell. The input command is accepted, executed, and the result is returned to the user.
Since Linux was very difficult to install and use as it is, the Linux distribution is a collection of programs required to use it. Typical ones are Ubuntu and Red Hut.
It provides additional functionality to Linux. When running application software on Linux, you need to download and convert the original source code. However, this takes a lot of time and effort, so the ** package ** is a compilation of the source code converted from the beginning.
In order to install application software, it may be necessary to install other application software that assists the operation. This is called a dependency, and each application software had to be stored in the correct order and location. Or if you have an updated program, you will need to remove the old version. ** Package Manager ** makes these tasks easier.