4 ms·

Yeah, my first thought was "this board looks great for testing big-endian". Would be nice to see comparisons to e.g. the G5.

faragon 9y ago
Sure. I bought back in the day a G4 Mac Mini just for that purpose (running both Linux and OSX) :-)
- grav 9y ago
  In which case do you need to test big endian? Compiler or low-level library development?
  - faragon 9y ago
    Mainly for networking or disk storage, and in general for anything involving storing integer data into raw packets that will reach different CPU architectures (e.g. load or store an integer from/to a memory buffer into/from a CPU register).
  - nullc 9y ago
    TD-linux develops codec libraries. I develop crypto code. Testing on BE is nice, not just because of endian neutral code but testing on something 'weird' can turn rare faults into common ones. Beyond endianness I've found interesting bugs by running code on HP-PA (stack grows in the reverse direction) and on Itanium (misalignment causes a trap to the kernel)... I wish there were a qemu supported fake architecture that made every optional decision differently (or at least every one that works with most code...).
hsivonen 9y ago
At what point will all big-endian usage be just developers testing big-endian with no users to use the results, and at what point shall we stop even testing? (Yesterday, I finally got around to making encoding_rs work on 64-bit big-endian systems by testing PPC64 in qemu. Then I timed out trying to get a 32-bit big-endian system with recent enough glibc to run Rust up and running in qemu, so I still haven't tested the 32-bit case... Unclear if anyone even cares.)
- gsnedders 9y ago
  With IBM's huge investment in better support for little-endian PPC (in hardware, in software development toolchains, and in software itself) it seems likely that many PPC users are going to slowly move away from little-endian. I can imagine some embedded uses, e.g. in network hardware, may well stick with big-endian because it fundamentally makes sense there, but I imagine it's going to become increasingly obscure.
  - gsnedders 9y ago
    My above comment is of course wrong, they're going to move away from big-endian to little-endian. Pretty sure I changed what I was saying half-way through. :)
- TD-Linux 9y ago
  MIPS is the other large big-endian case that's still in wide use (especially in home routers), however the machines are even more painfully slow to test on.
  - faragon 9y ago
    Most MIPS CPUs can run both BE and LE (MIPS-LE), although is usually tied to the kind of applications (e.g. most MIPS routers run in big endian mode)

faragon 9y ago

Sure. I bought back in the day a G4 Mac Mini just for that purpose (running both Linux and OSX) :-)

grav 9y ago
In which case do you need to test big endian? Compiler or low-level library development?
- faragon 9y ago
  Mainly for networking or disk storage, and in general for anything involving storing integer data into raw packets that will reach different CPU architectures (e.g. load or store an integer from/to a memory buffer into/from a CPU register).
- nullc 9y ago
  TD-linux develops codec libraries. I develop crypto code. Testing on BE is nice, not just because of endian neutral code but testing on something 'weird' can turn rare faults into common ones. Beyond endianness I've found interesting bugs by running code on HP-PA (stack grows in the reverse direction) and on Itanium (misalignment causes a trap to the kernel)... I wish there were a qemu supported fake architecture that made every optional decision differently (or at least every one that works with most code...).

hsivonen 9y ago

At what point will all big-endian usage be just developers testing big-endian with no users to use the results, and at what point shall we stop even testing? (Yesterday, I finally got around to making encoding_rs work on 64-bit big-endian systems by testing PPC64 in qemu. Then I timed out trying to get a 32-bit big-endian system with recent enough glibc to run Rust up and running in qemu, so I still haven't tested the 32-bit case... Unclear if anyone even cares.)

gsnedders 9y ago
With IBM's huge investment in better support for little-endian PPC (in hardware, in software development toolchains, and in software itself) it seems likely that many PPC users are going to slowly move away from little-endian. I can imagine some embedded uses, e.g. in network hardware, may well stick with big-endian because it fundamentally makes sense there, but I imagine it's going to become increasingly obscure.
- gsnedders 9y ago
  My above comment is of course wrong, they're going to move away from big-endian to little-endian. Pretty sure I changed what I was saying half-way through. :)
TD-Linux 9y ago
MIPS is the other large big-endian case that's still in wide use (especially in home routers), however the machines are even more painfully slow to test on.
- faragon 9y ago
  Most MIPS CPUs can run both BE and LE (MIPS-LE), although is usually tied to the kind of applications (e.g. most MIPS routers run in big endian mode)