Debian GNU/Linux 12 har stöd för 9 större arkitekturer och ett flertal variationer av varje arkitektur kända som ”varianter”.

Det här dokumentet täcker in installationen för 32-bit hard-float ARMv7--arkitekturen med Linux-kärnan. Om du letar efter information om någon av de andra arkitekturerna som Debian stöder kan du se på sidorna för Debian-porteringar.

The ARM architecture has evolved over time and modern ARM processors provide features which are not available in older models. Debian therefore provides three ARM ports to give the best support for a very wide range of different machines:

Technically, all currently available ARM CPUs can be run in either endian mode (big or little), but in practice the vast majority use little-endian mode. All of Debian/arm64, Debian/armhf and Debian/armel support only little-endian systems.

ARM-system är mycket mer heterogena än de som bygger på den i386/amd64-baserade PC-arkitekturen, så supportsituationen kan vara mycket mer komplicerad.

The ARM architecture is used mainly in so-called ”system-on-chip” (SoC) designs. These SoCs are designed by many different companies with vastly varying hardware components even for the very basic functionality required to bring the system up. System firmware interfaces have been increasingly standardised over time, but especially on older hardware firmware/boot interfaces vary a great deal, so on these systems the Linux kernel has to take care of many system-specific low-level issues which would be handled by the mainboard's BIOS/UEFI in the PC world.

At the beginning of the ARM support in the Linux kernel, the hardware variety resulted in the requirement of having a separate kernel for each ARM system in contrast to the ”one-fits-all” kernel for PC systems. As this approach does not scale to a large number of different systems, work was done to allow booting with a single ARM kernel that can run on different ARM systems. Support for newer ARM systems is now implemented in a way that allows the use of such a multiplatform kernel, but for several older systems a separate specific kernel is still required. Because of this, the standard Debian distribution only supports installation on a selected number of such older ARM systems, alongside the newer systems which are supported by the ARM multiplatform kernels (called ”armmp”) in Debian/armhf.

Följande system är kända för att fungera med Debian/armhf genom att använda multiplatform (armmp): kärnan:

Generally, the ARM multiplatform support in the Linux kernel allows running debian-installer on armhf systems not explicitly listed above, as long as the kernel used by debian-installer has support for the target system's components and a device-tree file for the target is available. In these cases, the installer can usually provide a working installation, but it may not be able to automatically make the system bootable. Doing that in many cases requires device-specific information.

When using debian-installer on such systems, you may have to manually make the system bootable at the end of the installation, e.g. by running the required commands in a shell started from within debian-installer.

Multiprocessor support — also called ”symmetric multiprocessing” or SMP — is available for this architecture. The standard Debian 12 kernel image has been compiled with SMP-alternatives support. This means that the kernel will detect the number of processors (or processor cores) and will automatically deactivate SMP on uniprocessor systems.

Having multiple processors in a computer was originally only an issue for high-end server systems but has become common in recent years nearly everywhere with the introduction of so called ”multi-core” processors. These contain two or more processor units, called ”cores”, in one physical chip.

Debian's support for graphical interfaces is determined by the underlying support found in X.Org's X11 system, and the kernel. Basic framebuffer graphics is provided by the kernel, whilst desktop environments use X11. Whether advanced graphics card features such as 3D-hardware acceleration or hardware-accelerated video are available, depends on the actual graphics hardware used in the system and in some cases on the installation of additional ”firmware” blobs (see Avsnitt 2.2, ”Enheter som kräver fast programvara”).

Nearly all ARM machines have the graphics hardware built-in, rather than being on a plug-in card. Some machines do have expansion slots which will take graphics cards, but that is a rarity. Hardware designed to be headless with no graphics at all is quite common. Whilst basic framebuffer video provided by the kernel should work on all devices that have graphics, fast 3D graphics invariably needs binary drivers to work. The situation is changing quickly but at the time of the bookworm release free drivers for nouveau (Nvidia Tegra K1 SoC) and freedreno (Qualcomm Snapdragon SoCs) are available in the release. Other hardware needs non-free drivers from 3rd parties.

Detaljer om grafikhårdvaraoch pekenheter kan hittas på https://wiki.freedesktop.org/xorg/. Debian 12 skickar med X.Org version 7.7.

Nästan alla nätverkskort (NIC) som stöds av Linux-kärnan stöds även av installationssystemet; modulära drivrutiner ska vanligtvis läsas in automatiskt.

På 32-bit hard-float ARMv7 finns stöd för de flesta inbyggda Ethernet-enheter och moduler för ytterligare PCI- och USB-enheter tillhandahålls.

Linux har stöd för ett stort antal maskinvaruenheter såsom möss, skrivare, skannrar, PCMCIA/CardBus/ExpressCard och USB-enheter. Dock krävs inte de flesta av dessa enheter vid installation av systemet.