Endian wars and anti-portability: this again?

https://dalmatian.life/2026/04/03/endian-wars-and-anti-portability-this-again/

by awilfox • 4 months ago

46 67 4 months ago

In closing, let me reiterate this point so it is crystal clear. If you are a maintainer of a libre software project and you refuse a community port to another architecture, you are doing a huge disservice to your community and to your software’s overall quality. As the Linux kernel has demonstrated, you can accept new ports, and deprecate old ports, as community demands and interest waxes and wanes.

Every feature has a cost and port to a different architecture has a huge cost in ongoing maintenance and testing.

This is open source. The maintainer isn’t refusing a port. The maintainer is refusing to accept being a maintainer for that port.

A person is always free to fork the open source project and maintain the port themselves as a fork.

nine_k• 4 months ago

Hmm, if the author of the port cares, why won't the author of the port become a maintainer of that port? This should be a two-way street.

CJefferson2• 4 months ago

In my experience, as someone who has gone through this as maintainer of two decent sized projects, that simply doesn't work.

The author of the 'port' probably doesn't know your whole codebase like you, so they are going to need help to get their code polished and merged.

For endian issues, the bugs are often subtle and can occur in strange places (it's hard to grep for 'someone somewhere made an endian assumption'), so you often get dragged into debugging.

Now let's imagine we get everything working, CI set up, I make a PR which breaks the big-endian build. My options are:

1) Start fixing endian bugs myself -- I have other stuff to do!

2) Wait for my 'endian maintainer' to find and fix the bug -- might take weeks, they have other stuff to do!

3) Just disable the endian tests in CI, eventually someone will come complain, maybe a debian packager.

At the end of the day I have finite hours on this earth, and there are just so few big endian users -- I often think there are more packagers who want to make software work on their machine in a kind of 'pokemon-style gotta catch em all', than actual users.

josephg• 4 months ago

If the community is offering you a port to an architecture, whether it is 4 days old or 40 years old, that means the community actively wants to use your software on it – otherwise, nobody would put in the effort. Ports like this are hard, and authors like me already know we are fighting an uphill battle just trying to make upstream projects care.

I've had plenty of opensource contributions over the years for some feature or other I don't care about. I used to accept these pull requests. But all too often, the person who wrote the patch disappears. Then for years I receive bug reports about a feature I didn't write and I don't care about. What do I do with those reports? Ignore them? Fix the bugs myself? Bleh.

I don't publish opensource projects so I can be a volunteer maintainer, in perpetuity, for someone else's feature ideas.

If its a small change, or something I would have done myself eventually, then fine. But there is a very real maintenance burden that comes from maintaining support for weird features and rare computer architectures. As this article points out, you need to actively test on real hardware to make sure code doesn't rust. Unfortunately I don't have a pile of exotic computers around that I can use to test my software. And you need to test software constantly or there's a good chance you'll break something and not notice.

That said, is there an easy way to run software in "big endian" mode on any modern computer? I'd happily run my test suite in big endian mode if I could do so easily.

zamadatix• 4 months ago

That said, is there an easy way to run software in "big endian" mode on any modern computer?

QEMU userspace emulation is usually the easiest for most "normal" programs IMO. Once you set it up you just run the other architecture binaries like normal binaries on your test system (with no need to emulate a full system). Very much the same concept as Prism/Rosetta on Windows/macOS for running x86 apps on ARM systems except it can be any target QEMU supports.

cpeterso• 4 months ago

A post about big-endian testing with QEMU was posted on HN just a few days ago:

https://news.ycombinator.com/item?id=47626462

https://www.hanshq.net/big-endian-qemu.html

ori_b• 4 months ago

What do I do with those reports? Ignore them? Fix the bugs myself? Bleh.

"I don't have access to a test environment, but if you want to write a fix, let me know and I may be able to point you in the right direction" is a perfectly reasonable response.

jaxelr• 4 months ago

This, a hundred times. The expectation shouldn't be that you must maintain all scenarios, environments, edge cases.

It's also reasonable to say I simply do not use this software the same way you do. The individual is empowered to fork, contribute and/or collaborate.

zephen8• 4 months ago

In closing, let me reiterate this point so it is crystal clear. If you are a maintainer of a libre software project and you refuse a community port to another architecture, you are doing a huge disservice to your community and to your software’s overall quality.

Linus Torvalds disagrees. Vehemently.

https://www.phoronix.com/news/Torvalds-No-RISC-V-BE

For those who don’t know, endianness is simply how the computer stores numbers. Big endian systems store numbers the way us humans do: the largest number is written first.

Really, what's first? You're so keen on having the big end first, but when it comes to looking at memory, you look... starting at the little end of memory first??? What's up with that?

I happen to prefer big endian systems in my own development life because they are easier for me to work with, especially reading crash dumps.

It always comes back to this. But that's not a good rationale for either the inconsistency of mixed-endianness where the least significant bit is zero but the most significant byte is zero, or true big endianness, where the least significant bit of a number might be a bit numbered 7 or numbered 15, or even 31 or 63, depending on what size integer it is.

(Porting to different endianness can help catch obscure bugs.)

Yeah, I'm sure using 9 bit bytes would catch bugs, too, but nobody does that either.

userbinator4• 4 months ago

BE was a huge mistake. Arabic numerals originated in a right-to-left language too.

depending on what size integer it is

That's the worst part about BE: values that have a size-dependent term in them, in addition to a subtraction. 2^n vs. 2^(l-n) and 256^N vs 256^(L-N).

According to Linus, BE has been "effectively dead" for at least a decade: https://news.ycombinator.com/item?id=9451284

pezezin3• 4 months ago

Arabic numerals originated in India, were languages are written left to right.

lovich• 4 months ago

I don’t have an opinion either way on this authors belief around the port being accepted upstream or not.

I did however learn a lot googling some of the terms they dropped and finding out things like PowerPC architecture getting and update as recently as 2025.

Several of their references I knew from my first tech leads mentioning their own early career. I am surprised at how much still has active development.

userbinator4• 4 months ago

If you want to keep software working on systems with a 9-bit byte or other weirdness, that's entirely on you. No one else needs or wants the extra complexity. Little endian is logical and won, big endian is backwards and lost for good reason. (Look at how arbitrary precision arithmetic is implemented on a BE system; chances are it's effectively LE anyway.)

yjftsjthsd-h5• 4 months ago

Little endian is logical and won, big endian is backwards and lost for good reason.

No, BE is logical, but LE is efficient (for machines).

lowbloodsugar• 4 months ago

No, BE is intuitive for humans who write digits with the highest power on the left.

LE is logical which is also why it is more efficient and more intuitive for humans once they get past “how we write numbers with a pencil”.

adrian_b3• 4 months ago

BE is not logical in any way, it is just a tradition, like the use of decimal numbers.

The use of automatic computers has forced a transition from the use of arbitrary conventions that did not have any logical motivation to the most efficient methods of data representation, like binary numbers in little-endian format.

Little-endian is more efficient even when you compute by pen on paper, if it feels awkward that is just because you were taught differently as a child.

There are special circumstances when a big-endian representation is the right choice, e.g. when you interpret a bit string as a binary polynomial, in order to implement an error-detection code with a CRC. However, for general-purpose numbers, little-endian is the optimum choice.

pezezin3• 4 months ago

LE is not "logical", it won because the IBM PC compatible won, simple as that.

ozgrakkurt2• 4 months ago

You don't need the "Little endian is logical" part.

Most people just don't care and can't be bothered to spend time making sure code is "endian portable".

Couldn't care less if it is easier to "read in crash dumps" TBH.

I don't even write server code to be portable to anything other than x86_64 or lately just use avx512 without any fallback since it is not needed in practice.

I'm not doing anything people care about probably but I imagine it is a similar feeling for people that do.

I would rather have small software that compiles fast than to add 50 #ifdef into it and make it burn my eyes, and spend time thinking "but would this work in big endian"

smj-edison• 4 months ago

I happen to prefer big endian systems in my own development life because they are easier for me to work with, especially reading crash dumps.

If hex editors were mirrored both left to right and right to left, would it be easier to read little endian dumps?

ronsor• 4 months ago

xxd has the `-e` option for exactly this use case:

    -e          little-endian dump (incompatible with -ps,-i,-r).

bastawhiz• 4 months ago

I think the tricky thing here is that I simply don't have the time, patience, or resources to maintain this stuff. Let's say I have a LE-only project. Someone ports it to work on BE. Now it needs ci for BE. I write a patch in the future and the BE tests fail. Now I need to fix them. Potential contributors need to get the tests to pass. Who's using BE, though? Is the original porter even still using it?

The author betrays their own point with the anecdote about 586 support: they had tests, the tests passed, but the emulator was buggy, masking the issue. Frankly, if you're the Linux kernel and nobody has the hardware to run the tests on an actual device, it says a lot. But it also shows that qemu is struggling to make it work if the emulation isn't working as it should. How is someone who runs a small project supposed to debug a BE issue when you might have to debug the emulator when a user report comes in?

For me, I'll always welcome folks engaging with my work. But I'll be hesitant to take on maintenance of anything that takes my attention away from delivering value to the overwhelming majority of my users, especially if the value of the effort disappears over time (e.g., because nobody is making those CPUs anymore).

jandrewrogers• 4 months ago

The glaring omission from that long post is the term "opportunity cost".

Ensuring a code base indefinitely supports arbitrary architectures carries a substantial code architecture cost. Furthermore, it is difficult to guarantee testing going forward or that the toolchains available for those architectures will continue to evolve with your code base. I'm old enough to have lived this reality back when it was common. It sucked hard. I've also written a lot of code that was portable to some very weird silicon so I know what that entails. It goes far beyond endian-ness, that is just one aspect of silicon portability.

The expectation that people should volunteer their time for low ROI unpleasantness that has a high risk of being unmaintainable in the near future is unreasonable. There are many other facets of the code base where that time may be better invested. That's not "anti-portable", it is recognition of the potential cost to a large base of existing users when you take it on. The Pareto Principle applies here.

Today, I explicitly only support two architectures: 64-bit x86 and ARM (little-endian). It is wonderful that we have arrived at the point where this is a completely viable proposition. In most cases the cost of supporting marginal users on rare architectures in the year 2026 is not worth it. The computing world is far, far less fragmented than it used to be.

nextaccountic3• 4 months ago

Why not wasm?

jltsiren2• 4 months ago

Wasm is in an awkward place, because Memory64 is widely but not universally supported. Which means that if you want to support Wasm, you probably have to support 32-bit environments in general. Depending on the project, that can be trivial, but it may also require you to rewrite a lot of low-level code in the project and its dependencies.

pjc50• 4 months ago

Today, I explicitly only support two architectures: 64-bit x86 and ARM (little-endian). It is wonderful that we have arrived at the point where this is a completely viable proposition. In most cases the cost of supporting marginal users on rare architectures in the year 2026 is not worth it.

This - and efforts to reintroduce BE should be resisted in the same way as people who want to drive on the other side of the road for pure whimsy.

I note that we've mostly converged on one set of floating point semantics as well, although across a range of bit widths.

lmm• 4 months ago

Ensuring a code base indefinitely supports arbitrary architectures carries a substantial code architecture cost.

I'd say just the opposite; it nudges you towards well-factored approaches and ultimately carries a code architecture benefit, just like having automated tests or using structured programming.

tacitusarc• 4 months ago

For a relatively small set of dimensions this is true. But the more abstractions the code needs to accommodate, the trickier and more prone to leaky abstractions it becomes. Removing one axis of complexity can be incredibly helpful.

chmod775• 4 months ago

Big endian systems store numbers the way us humans do: the largest number is written first.

Obviously the author was trying to just give a quick example to aid visualization, but here's some nitpicking: I can probably come up with at least IV writing systems used by humans that don't use "big endian" for numbers. Or either, really.

Examples: Tally marks, Ancient Egyptian numerals, Hebrew and Attic numerals, and obviously Roman numerals.

Also lots languages in written form order words somewhat... randomly (French, Danish, old English, ...).

pezezin3• 4 months ago

Roman numerals are big endian though. The current year is written as MMXXVI, not IVXXMM.

adrian_b3• 4 months ago

The convention that smaller number written to the left of bigger numbers should be subtracted instead of added, is a later addition to the Roman numerals.

The earlier system would write VIIII instead of IX.

With the original Roman numerals, the order of writing was completely irrelevant, because all parts were added and addition is comutative, so VIIII is the same as IIIIV or IIIVI.

Even in the later variant of Roman numerals, you can change the order of many symbols without changing the value.

tjwebbnorfolk• 4 months ago

and you refuse a community port to another architecture, you are doing a huge disservice to your community

Someone who has a computer that my software can't run on isn't in my community. If they really want to use the software, they have the option of: 1) get a different computer, or 2) maintain their own custom-special port of my software forever.

In other words, they have to JOIN the community if the want the BENEFITS of the community. It's not my job to extend my community to encompass every possible use case and hardware platform.

dataflow3• 4 months ago

The whole thing rests on these assertions:

It is usually easy to write code that is endian-safe. Any code that is not endian-safe is poorly written and harder to maintain at best, and possibly obscuring security bugs at worst. Any project maintainer should be jumping for joy when they receive a patch adding a big-endian port of their project, especially if it includes reports that tests pass and the software works. That is the sign of a codebase that has a level of sanity that should not be noteworthy, yet is.

And every single sentence is false.

The tower collapses once you remove any of the bases, let alone all of them.

ozgrakkurt2• 4 months ago

Main issue I have with it is access to testing. It is extra work to be able to test big endian. I don’t want to think about big endian while writing code but it would be ok to do it if I could easily run tests in big endian.

burnt-resistor• 4 months ago

I'm glad I did my undergrad at UC Davis in the mid '00s that valued portability and well-defined behavior rather than proprietary or implementation-specific, non-portable assumptions. The lazy, rationalizing throwing out the baby with the bathwater folks are disappointments to engineering excellence.

CJefferson2• 4 months ago

It's very hard in most language to portably handle endian-ness -- almost by definition, if your code has an issue where endian-ness effects behavior, it's not-portable.

I tend to take another view point (while I understand yours) -- if it's not tested, it doesn't work. And nowadays it's really hard to test big-endian code. I don't have one, I find running different-endian software in QEMU really annoying and difficult.

sparkie• 4 months ago

Reminder that the computer's endianness shouldn't matter. You should only care about the endianness of the streams your reading from and writing to.

https://commandcenter.blogspot.com/2012/04/byte-order-fallac...

rcxdude• 4 months ago

This. In the specific case of endianness, if you have bugs with it you're probably already doing something wrong. But in general, supporting weird architectures is not something that should be expected to be foisted on any arbitrary projects, especially if the person who does the initial port just disappears again.

adrian_b3• 4 months ago

That should have been true, but unfortunately the most popular programming languages do not have distinct data types for bit strings, non-negative numbers, integer residues a.k.a. modular numbers, binary polynomials and binary polynomial residues.

So in C and the like one uses "unsigned" regardless if bit strings or non-negative numbers are needed.

Because no explicit conversions between bit strings and numeric types are used, it is frequent to have expressions where a certain endianness of the numbers is assumed implicitly.

This is the most frequent source of bugs that manifest when a program is run on a machine with an opposite endianness than assumed in the program.

nananana9• 4 months ago

The more portable and general your code is, the less use you can make of the hardware.

The article touches on the 32/64 bit split. A lot of the code I write nowadays doesn't run on 32 bit systems, not because it uses a lot of RAM, but because having an actually usable 64-bit address range enables you to write programs that you couldn't on 32 bit.

If you want to write code that works on big endian systems, systems where pointers aren't integers or bytes aren't 8 bits, all the power to you. I'm happy to pretend big endian is not a thing and focus my limited manpower on the hardware that my program will run on.

Joker_vD3• 4 months ago

If someone has managed to make your software work on 32-bit, you should accept that port as it will help ensure your software remains efficient even on 64-bit systems. After all, if every program is required to fit in 4 GB, that means the 32 GB RAM workstation you are spoiled with can run a full 8 programs on it!

This is just so fundamentally wrong that it makes the whole rest of TFA highly suspect (and yes, most of the rest of it is also pretty wrong).

Cold_Miserable• 4 months ago

Small indian. Starting at zero and extending is logical. Big indian is dumb and confusing.

Endian wars and anti-portability: this again?

Related Stories