17.1.2 package repository
Debian 기반의 배포판은 해당 운영체제가 설치된 시스템에서 설치하여 사용할 수 있는 기본적인 프로그램 목록 정보를 관리하고 있는데, 이를 package repository라고 한다. Debian 기반의 배포판은 인터넷 상에서 package repository server를 운영하고 있으며, package repository에서 package를 검색하고, 설치하고, package를 조작할 수 있는 도구인 Advanced Packaging Tool (APT)라는 package management system을 제공해 준다.
17.1 package manager system
17.1.1 package
package란 시스템이 요구하는 형식으로 프로그램을 배포하여 설치할 수 있도록 필요한 모든 자료가 사전 정의된 방식으로 구성되어 있는 일련의 파일들의 묶음을 의미한다. package는 computer program뿐만 아니라 그 프로그램을 적용하는데 필요한 metadata를 포함하고 있다. Package metadata는 package에 대한 설명, version, 그리고 다른 package와의 dependency(먼저 설치되어야 하는 다른 package와의 관계)에 대한 정보를 함께 가지고 있다.
Chapter 17 프로그램 설치와 Upgrade
Chapter 주요 내용
여기서는 Raspberry Pi 시스템에 프로그램을 추가적으로 설치하는 절차에 대해서 설명하고자 한다. 또한 이전에 설치한 프로그램을 제거하거나 upgrade하는 방법 등에 대해서도 설명할 것이다.
다음과 같은 항목에 대한 내용을 포함하고 있다.
■ package manager system
■ package 관리도구
■ 설치 프로그램 source 확보
■ 프로그램 설치 및 재설치
■ 프로그램 설치 제거
■ 프로그램 update 및 upgrade
■ system kernel 및 firmware upgrade
17.8 Upgrade of System Kernel and Firmware
The kernel and firmware of the Raspberry Pi system are continuously being upgraded to fix errors, improve system performance, and provide additional functionality. If a certain period of time has elapsed since the installation of the Raspberry Pi system, the currently installed system may be different from the system of the latest version. Also, if a specific application is developed based on the latest version of the system, it may cause an error if the program is used on the system of the previous version. Therefore, it is sometimes necessary to upgrade the kernel and firmware.
17.7.3 “apt-get upgrade” Command- Reflect Updated Program
If a program already installed on the system is modified afterward, it is necessary to replace it with a new program. This is done using “upgrade” command in “apt-get” command.
17.7.2 “apt-get update” command – Update Local Package DB
The “update” command is used to update the program package information in the local package repositoroty installed on the system to the latest version. When this command is executed, the package information stored in the local package repository is updated to the latest version, and the latest package file for the installed program is downloaded and archived.
17.7 Update and Upgrade of Program
17.7.1 Upgarde of Program
The package managed by the package repository manages software distribution and metadata in the form of archive files. When a package is installed on a specific computer, the metadata contained in the package is stored in the local package database. In this local package database, typical information such as software dependency and version is managed. The package manager uses this local package database to prevent discrepancies between software and missing essential items.
17.6.2 Cleaning Program Package File
During the process of installing or upgrading programs, the related program package file is downloaded and stored in the local repository “/var/cache/apt/archives/”. These files are not deleted and remain intact even if the program installation is completed or the program is removed. If these files continue to accumulate, it will take up unnecessary storage space in the system, so it’s a good idea to remove any files that is no longer needed.
17.6 Uninstalling Programs and Cleaning Files
17.6.1 Uninstalling Programs
If you no longer need the installed programs, you should remove them. There are several ways to remove installed programs.
17.5 Installing and Reinstalling Program
17.5.1 Comparison of Installation by Source Distribution Method
In the Raspbian operating system, it is standard to manage and distribute programs using the package repository, but you can distribute, install, and use programs without using this method.