4.1. 安装方式

Debian系统可以从不同媒介安装，只要机器BIOS允许的话。可以从光驱，U盘，甚至是网络引导安装。

基本知识 BIOS, 硬件/软件界面

主板（连接所有外设的电子板）上的BIOS（基本输入／输出系统）在引导操作系统之前被执行。它在背后作为计算机硬件和操作系统（这里是指Linux内核）连接的接口。

4.1.1. 从CD-ROM/DVD-ROM安装

最常见的安装介质是从CD光驱（或者DVD光驱，都一样）：计算机从此处引导，然后安装程序接管。

Various CD-ROM families have different purposes: netinst (network installation) contains the installer and the base Debian system; all other programs are then downloaded. Its “image”, that is the ISO-9660 filesystem that contains the exact contents of the disk, only takes up about 150 to 280 MB (depending on architecture). On the other hand, the complete set offers all packages and allows for installation on a computer that has no Internet access; it requires around 16 DVD-ROMs (or 4 Blu-ray disks). There is no more official CD-ROMs set as they were really huge, rarely used and now most of the computers use DVD-ROMs as well as CD-ROMs. But the programs are divided among the disks according to their popularity and importance; the first disk will be sufficient for most installations, since it contains the most used software.

最后一种类型的安装镜像文件就是熟知的mini.iso, 该文件仅可作为安装器的副产品。 该镜像仅包含配置网络所需的最小需求，其它的任何东西都需要下载（包括安装器本身部分，所以新版本的安装器发布时该镜像就没有用了）。这些镜像可在常规的Debian镜像站点的dists/*release*/main/installer-*arch*/current/images/netboot/目录下找到。

技巧 多架构盘

大部分安装 CD 和 DVD 光驱只适合于特定的硬件架构。如果你希望下载完整镜像，你必须仔细选择适合你硬件架构的那种。

Some CD/DVD-ROM images can work on several architectures. We thus have a CD-ROM image combining the netinst images of the i386 and amd64 architectures.

To acquire Debian CD-ROM images, you may, of course, download them and burn them to disk. You may also purchase them, and, thus, provide the project with a little financial support. Check the website to see the list of DVD-ROM image vendors and download sites.

→ https://www.debian.org/CD/index.html

4.1.2. 从U盘引导

因为大多数计算机能够从 USB 设备启动，所以你也可以从 USB 盘（小闪存盘）安装 Debian。

安装指南说明了怎样做一个包含debian-installer的 USB 盘。安装过程很简单， 因为i386 和 amd64 架构的 ISO 镜像是混合（在一起）的， 从 USB 盘引导像从 CD 引导一样。

You must first identify the device name of the USB key (ex: /dev/sdb); the simplest means to do this is to check the messages issued by the kernel using the dmesg command. Then you must copy the previously downloaded ISO image (for example, debian-10.0.0-amd64-netinst.iso) with the command cat debian-10.0.0-amd64-netinst.iso >/dev/sdb; sync. This command requires administrator rights, since it accesses the USB key directly and blindly erases its content.

A more detailed explanation is available in the installation manual. Among other things, it describes an alternative method of preparing a USB key that is more complex, but that allows to customize the installer’s default options (those set in the kernel command line).

→ https://www.debian.org/releases/stable/amd64/ch04s03

4.1.3. 从网络引导安装

许多的 BIOS 允许从网络上下载内核和一个最小化的文件系统镜像并直接以此进行系统引导。这种方法（有几种不同的名称，比如 PXE 或者 TFTP 引导）在计算机没有光驱、或者 BIOS 无法从其它介质进行引导的时候就是最后的一条救命稻草了。

这种安装方法分两个步骤。第一步，在引导计算机时， BIOS（或者网卡）发出一个 BOOTP/DHCP 请求以自动获取 IP 地址。BOOTP 或 DHCP 服务器返回的响应将包含一个文件名以及当前网络的设定情况。在配置好网络后，客户端计算机发出一个 TFTP（简单文件传输协议）请求，所请求的文件名称由先前的响应决定。在文件获取完成后，它将作为一个引导程序被计算机执行。此后，它将会启动 Debian 安装程序，安装程序将正常运行，就好像它是从硬盘、CD-ROM 或是 U 盘引导运行而来的那样。

All the details of this method are available in the installation guide (“Preparing files for TFTP Net Booting” section).

→ https://www.debian.org/releases/stable/amd64/ch05s01#boot-tftp-x86

→ https://www.debian.org/releases/stable/amd64/ch04s05

4.1.4. 其他安装方式

When we have to deploy customized installations for a large number of computers, we generally choose an automated rather than a manual installation method. Depending on the situation and the complexity of the installations to be made, we can use FAI (Fully Automatic Installer, described in 第 12.3.1 节 “Fully Automatic Installer (FAI)”), or even a customized installation DVD with preseeding (see 第 12.3.2 节 “预设值 Debian 安装”).