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Comment by Jonnax | Hacker News Reader

So I don't know much about kernel development.

How many other languages ========================= Language Files ========================= ASN.1 11 Assembly GNU Style Assembly 1296 Autoconf 6 Automake 3 BASH 54 C C Header 21110 C++ C++ Header 2 CSS 1 Device Tree 3351 Gherkin (Cucumber) 1 Happy HEX 1 INI 1 JSON LD Script 15 Makefile 2587 Module-Definition 2 Perl Python 118 ReStructuredText 2621 Ruby 1 Shell 556 SVG Plain Text 3230 Unreal Script 5 Vim script 1 XSL 15 YAML 921 ========================= Total ========================= apart from C are there in the kernel?

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Depends how you define "in the kernel". In terms of what is compiled into the kernel image, it's C plus small pieces of assembler (both inline and in separate files). This proposal (if it ever happens) would be about adding Rust to that. If you mean the tree used to build the kernel, you could say it includes shell script, Makefiles, the Kconfig descriptions, and more. If you mean all the bits you need to have a very minimally working system which boots, you'd want to include all the languages used for the necessary userspace tools like the init system and udev (although the vast majority of that is also C and shell scripts).

I'm a bit uninformed as well. Obviously it must use assembly in some places, it has makefiles for building and some scripts in perl. Here's what a cloc clone has to say.

    tokei ====================================================== Lines         Code     Comments       Blanks ====================================================== 484          343           33          108 3         2751         2450            0          301 370153       270691        56418        43044 347          303           20           24 31           23            3            5 1991         1438          321          232 28971     19846129     14634535      2351170      2860424 6056898      4465297      1010398       581203 8         2313         2016           68          229 125           59           55           11 137           80           29           28 900862       735380        54238       111244 252          174           50           28 9         5750         5061            0          689 86           86            0            0 7            3            3            1 328       174872       174872            0            0 412          317           48           47 64666        43896        10957         9813 124          109            0           15 53        40583        31126         3931         5526 36932        29072         2980         4880 548840       417105            0       131735 29           25            0            4 85666        59725        10972        14969 59        39038        37555         1405           78 239573            0       197373        42200 716          446          162          108 42           33            6            3 300          183           78           39 91167        72962         3985        14220 ====================================================== 65340     28511276     20985365      3704703      3821208 ======================================================

The Unreal Script is for the new 3D menuconfig ;)

Someone should replace that with GDscript.

I was surprised to see C++ in there, but I understand it is simply some of the user-space tooling (in particular, some small parts of the perf tool are written in C++, in order to embed clang/LLVM.)

Likewise, Perl/Python/Ruby are just scripts included for various purposes (such as building documentation).

Interestingly, some of the assembler code included in the kernel is generated by Perl scripts (crypto code for ARM and MIPS). Perl is also used to compile "SCSI SCRIPTS" which are used by the NCR 53c810 SCSI driver.

Assembler. Although there is a movement to port assembler to c.

Which is impossible with ISO C alone, so it will either stay Assembly, just written inline, or replaced by CPU compiler specific intrinsics, yet another GCC C feature.

It's true that some of it will remain assembly forever, but there are large chunks of existing assembly in the kernel that can be ported to regular C and where the current code paths are getting too long to be effectively maintainable in assembly - you can split out the parts that specifically touch magic registers, etc etc and keep those in asm while moving more complex logic into C.

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