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Well, and IBM switched Power to little endian recently (the machines are dual endian, but all the new OSs are littl endian only). Power was the main BE architec

Well, and IBM switched Power to little endian recently (the machines are dual endian, but all the new OSs are littl endian only). Power was the main BE architecture left. Most arm machines are dual endian, and NetBSD supports both, but almost everyone uses little endian on arm. There is a bit of big endian mips around still, eg the Cavium network appliances.

aduitsis 12y ago
SPARC is also big endian.
bandrami 12y ago
IBM also for years screamed at devs that you can't rely on a PPC system being BE. Which means all oldworld MacOS software was at least theoretically written by people who couldn't tell you what byte order they were writing for. (How seriously the devs took that admonition is a different question.)
- vonmoltke 12y ago
  I was writing real-time signal processing software for POWER as recently as three years ago. I'm not even aware that was IBM's position, and they were our partners on the venture. That said, it really didn't matter because all our software had to build and run on x86-64 anyway, so all the endian-specific code was wrapped in preprocessor directives. We could have changed the endianness with a single makefile change.
  - bandrami 12y ago
    I'm not even aware that was IBM's position Yeah, I said it badly. IBM wouldn't guarantee Apple that Power would always support BE, so Apple pushed (or tried to) developers not to assume that.
    - vonmoltke 12y ago
      That makes sense. IBM knew we were focused on the POWER7 blades and that our backup plan was their Intel blades, so they probably figured the warning wouldn't be relevant to us.
- duskwuff 12y ago
  The PowerPC architecture was bi-endian, but classic Mac OS was very definitely big-endian. The only situation where the CPU would switch to little-endian would be if it was running Virtual PC. (And even then, it'd switch back for other applications.)
  - bandrami 12y ago
    Sorry, yeah, I stated that badly: Apple kept screaming at devs that IBM couldn't be guaranteed to keep the arch bi-endian, so Apple couldn't guarantee a big-endian platform and developers shouldn't assume one.
weland 12y ago
In the meantime, almost every bytestream sent over networks on planet Earth is BE, regardless of whether it's sent by or to a LE or BE machine.
- JoeAltmaier 12y ago
  Which is the great tragedy of our age. What a colossal waste
  - smorrow 12y ago
    It's the same C code doing IP, going through the same steps and the same number of steps, whether the underlying machine is little- or big-endian. So if you're saying about wasted cycles...
    - JoeAltmaier 12y ago
      The waste is every little-endian machine (almost all machines) converting every packet to big-endian for 'the wire', then converting back again when received. Its all a pointless self-flagellation.
      - smorrow 12y ago
        Any sensible code is going to have to do that stuff whether the machine's endianness matches IP's or not, though. It happens on BE boxes too. It's either that or write completely different code for different CPUs.
        JoeAltmaier 12y ago
        The OPs point was, there are essentially no more BE boxes.
        limeyx 12y ago
        Not for networking...ntohl/htonl and friends are no-ops (macros) on BE machines ... zero overhead
eliben 12y ago
PowerPCs are still 32 bit though, and fairly popular in the uController space [http://en.wikipedia.org/wiki/PowerPC http://en.wikipedia.org/wiki/PowerPC]
- vonmoltke 12y ago
  POWER != PowerPC. POWER processors through the POWER4 generally implemented the PowerPC ISA, but were not "PowerPC" chips. Also, there is a 64-bit PowerPC ISA; that is what the POWER4 implemented. It just doesn't get much use in embedded contexts because it isn't necessary and costs more.
Shivetya 12y ago
Odd, iSeries and pSeries are BigEndian, even Z is. On the iSeries it has no bearing on application programmers except when using transformation products to other platforms.
jk 12y ago
There are quite a few big endian MIPS devices. Many Chinese processor vendors (Mediatek, Rockchip, etc.) still use MIPS and have big endian configuration. Most common are TV SoCs and networking chips like WiFi SoCs.
StillBored 12y ago
And while it was probably a "good" idea, the implementation was terrible. Absolutely zero binary compatibility between SLES11 on a POWER7 and SLES12 on a POWER8 (same for RHEL). I think the official line was that compatibility comes in the form of being able to run the older OS in a VM... This is worse than the HP-UX PA to IA transition, the mac 68k to PPC, or PPC to x86, transition/etc. The least they could have done was some kind of elf loader, and some fat libraries that flips the execution mode for one generation while everyone transitions. The stated claim was to make it easier for people to transition to POWER from x86 (aka little porting effort), but what they really did was screw their existing customers by requiring them to port their software (big porting effort). I question, why if I'm going to spend the effort to port from BE POWER to LE POWER why I wouldn't just port to x86...

aduitsis 12y ago

SPARC is also big endian.

bandrami 12y ago

IBM also for years screamed at devs that you can't rely on a PPC system being BE. Which means all oldworld MacOS software was at least theoretically written by people who couldn't tell you what byte order they were writing for. (How seriously the devs took that admonition is a different question.)

vonmoltke 12y ago
I was writing real-time signal processing software for POWER as recently as three years ago. I'm not even aware that was IBM's position, and they were our partners on the venture. That said, it really didn't matter because all our software had to build and run on x86-64 anyway, so all the endian-specific code was wrapped in preprocessor directives. We could have changed the endianness with a single makefile change.
- bandrami 12y ago
  I'm not even aware that was IBM's position Yeah, I said it badly. IBM wouldn't guarantee Apple that Power would always support BE, so Apple pushed (or tried to) developers not to assume that.
  - vonmoltke 12y ago
    That makes sense. IBM knew we were focused on the POWER7 blades and that our backup plan was their Intel blades, so they probably figured the warning wouldn't be relevant to us.
duskwuff 12y ago
The PowerPC architecture was bi-endian, but classic Mac OS was very definitely big-endian. The only situation where the CPU would switch to little-endian would be if it was running Virtual PC. (And even then, it'd switch back for other applications.)
- bandrami 12y ago
  Sorry, yeah, I stated that badly: Apple kept screaming at devs that IBM couldn't be guaranteed to keep the arch bi-endian, so Apple couldn't guarantee a big-endian platform and developers shouldn't assume one.

weland 12y ago

In the meantime, almost every bytestream sent over networks on planet Earth is BE, regardless of whether it's sent by or to a LE or BE machine.

JoeAltmaier 12y ago
Which is the great tragedy of our age. What a colossal waste
- smorrow 12y ago
  It's the same C code doing IP, going through the same steps and the same number of steps, whether the underlying machine is little- or big-endian. So if you're saying about wasted cycles...
  - JoeAltmaier 12y ago
    The waste is every little-endian machine (almost all machines) converting every packet to big-endian for 'the wire', then converting back again when received. Its all a pointless self-flagellation.
    - smorrow 12y ago
      Any sensible code is going to have to do that stuff whether the machine's endianness matches IP's or not, though. It happens on BE boxes too. It's either that or write completely different code for different CPUs.
      - JoeAltmaier 12y ago
        The OPs point was, there are essentially no more BE boxes.
      - limeyx 12y ago
        Not for networking...ntohl/htonl and friends are no-ops (macros) on BE machines ... zero overhead

eliben 12y ago

PowerPCs are still 32 bit though, and fairly popular in the uController space [http://en.wikipedia.org/wiki/PowerPC http://en.wikipedia.org/wiki/PowerPC]

vonmoltke 12y ago
POWER != PowerPC. POWER processors through the POWER4 generally implemented the PowerPC ISA, but were not "PowerPC" chips. Also, there is a 64-bit PowerPC ISA; that is what the POWER4 implemented. It just doesn't get much use in embedded contexts because it isn't necessary and costs more.

Shivetya 12y ago

Odd, iSeries and pSeries are BigEndian, even Z is. On the iSeries it has no bearing on application programmers except when using transformation products to other platforms.

jk 12y ago

There are quite a few big endian MIPS devices. Many Chinese processor vendors (Mediatek, Rockchip, etc.) still use MIPS and have big endian configuration. Most common are TV SoCs and networking chips like WiFi SoCs.

StillBored 12y ago

And while it was probably a "good" idea, the implementation was terrible. Absolutely zero binary compatibility between SLES11 on a POWER7 and SLES12 on a POWER8 (same for RHEL). I think the official line was that compatibility comes in the form of being able to run the older OS in a VM... This is worse than the HP-UX PA to IA transition, the mac 68k to PPC, or PPC to x86, transition/etc. The least they could have done was some kind of elf loader, and some fat libraries that flips the execution mode for one generation while everyone transitions. The stated claim was to make it easier for people to transition to POWER from x86 (aka little porting effort), but what they really did was screw their existing customers by requiring them to port their software (big porting effort). I question, why if I'm going to spend the effort to port from BE POWER to LE POWER why I wouldn't just port to x86...