Wow... A speculative branch prediction path actually get's preemptively executed despite the branch outcome? No matter if the execution has side-affects??? That's quite amazing. Are modern CPUs doing speculative execution like this and just put extra safeguards around affects or do they just prefetch / decode instructions now-a-days?
I thought the design flaws of the Xbox 360 cooling system had more to do with Microsoft than any inherent design flaw by IBM. I assumed that switching to x86 processors let Microsoft leverage their native developer tools from Windows which helped developers.
"Microsoft did not reveal the cause of the issues publicly until 2021, when a 6-part documentary on the history of Xbox was released. The Red Ring issue was caused by the cracking of solder joints inside the GPU flip chip package, connecting the GPU to the substrate interposer, as a result of thermal stress from heating up and cooling back down when the system is power cycled."
I don't have any solid numbers on me, but I believe early 360s failing wasn't just widespread; it was straight up most of them dying within the first couple years. It's honestly insane they more or less got away with that. And I guess also speaks to how much Microsoft was killing it in that era that people were willing to go through multiple console RMAs (which I heard was a terrible, slow, and unreliable process) to play 360 games. How far they've fallen.
> It is interesting that IBM dominated this generation of consoles, and was vanquished in the next.
IBM's Power was the only logical option at the time.
These consoles were being designed around 2000. Intel and AMD weren't partnering on bespoke CPUs at that time. I don't even think AMD would have been considered a viable partner. Neither had viable 64 bit options and part of console marketing at the time was the ever increasing bit depths.
Prior console generations had use MIPS which wasn't keeping up with ever increasing performance expectations and players like Toshiba and Sony were looking for a higher performance CPU architecture. IBM's Power architecture was really the only option. Sony, Toshiba, and IBM partnered to develop their a new 64 bit microarchitecture called Cell.
Microsoft's first console was basically a PC and that's how everyone saw it. The 360 was an opportunity for Microsoft to show that it could compete with the big boys. It was also an opportunity to keep a toe dipped in RISC, because it had dropped support for RISC CPUs with Windows 2000.
Yeah that part didn't make sense, not to mention that neither the PS3 nor the 360 were running 64-bit software. They didn't have enough memory for it to be worth it.
Parts of the 360 did. The hypervisor ran in 64bit mode, and use multiple simultaneous mirrors of physical address space with different security properties as part of its security model.
you don't need memory to make 64 bit software worth it. Just 64 bit mathematics requirements. Which basically no video game console uses as from what I understand 32-bit floating point continue to be state of the art in video game simulations
Fundamentally it's still a memory limitation, just in terms of memory latency/cache misses instead of capacity. If you double the size of your numbers you're doubling the space it takes up and all the problems that come with it.
No it isn't. The 64-bit capabilities of modern CPUs have almost nothing to do with memory. The address space is rarely 64 bits of physical address space anyways. A "64-bit" computer doesn't actually have the ability to deal with 64 bits of memory.
If you double the size of numbers, sure it takes up twice the space. If the total size is still less that one page it isn't likely to make a big difference anyways. What really makes a difference is trying to do 64-bit mathematics with 32-bit hardware. This implies some degree of emulation with a series of instructions, whereas a 64-bit CPU could execute that in 1 instruction. That 1 instruction very likely executes in less cycles than a series of other instructions. Otherwise no one would have bothered with it
The original 8087 implemented 80-bit operands in its stack.
It would also process binary-coded decimal integers, as well as floating point.
"The two came up with a revolutionary design with 64 bits of mantissa and 16 bits of exponent for the longest-format real number, with a stack architecture CPU and eight 80-bit stack registers, with a computationally rich instruction set."
"Bitness" of a CPU almost always refers to memory addressing.
Now you could build a weird CPU that has "more memory" than it has addressable width (the 8086 is kind of like this with segmentation and 8/16 bit) but if your CPU is 64 bit you're likely not to use anything less than 64 bit math in general (though you can get some tricks with multiple adds of 32 bit numbers packed).
But a 32 bit CPU can do all sorts of things with larger numbers, it's just that moving them around may be more time-consuming. After all, that's basically what MMX and friends are.
You have to remember that the AMD and Intel of today are very different companies than they were 20-25 years ago. AMD split off it's fab capabilities, acquired ATI, adopted TSMC as a fab, and developed a custom silicon business.
At that time AMD wasn't in the custom CPU business, AMD64 was a new unproven ISA, and x86 based CPUs of that time were notoriously hot for a console. These were also some of the reasons why Microsoft moved away from the Pentium III it had used in the original Xbox.
The PS3 was launched in 2006 but the hardware design was decided years earlier to provide a reference platform for the software.
Voltage glitching. An outside attacker who has direct, extremely fine-grained control over the power supply to the chip can cause it to brown out for one instruction cycle, preventing a result of an instruction from being written.
With enough sophistication, physical access is more powerful than root access, no exceptions.
Wow... A speculative branch prediction path actually get's preemptively executed despite the branch outcome? No matter if the execution has side-affects??? That's quite amazing. Are modern CPUs doing speculative execution like this and just put extra safeguards around affects or do they just prefetch / decode instructions now-a-days?
It is interesting that IBM dominated this generation of consoles, and was vanquished in the next.
The high failure rates of the Xbox 360 did not help.
https://en.wikipedia.org/wiki/Xbox_360_technical_problems
I thought the design flaws of the Xbox 360 cooling system had more to do with Microsoft than any inherent design flaw by IBM. I assumed that switching to x86 processors let Microsoft leverage their native developer tools from Windows which helped developers.
The main issue was revealed to be solder.
"Microsoft did not reveal the cause of the issues publicly until 2021, when a 6-part documentary on the history of Xbox was released. The Red Ring issue was caused by the cracking of solder joints inside the GPU flip chip package, connecting the GPU to the substrate interposer, as a result of thermal stress from heating up and cooling back down when the system is power cycled."
And there was the same problem with early PS3s, on Nvidia's GPU package...it was a fairly widespread problem at the time.
And Apple iBook G3s too. There's a whole thing with owners reflowing the GPU: https://www.instructables.com/Fixing-the-infamous-iBook-scre...
I seem to recall baking PC nvidia GPU boards in your oven was a reasonably common out-of-warranty fix around that era.
I had to do this with my MacBook Pro models early 2015 and late 2017.
It seems like there was a period in time when solder just wasn’t done well, it seems like.
IIRC this is to do with the phase in of RoHS and bad lead free solder
I don't have any solid numbers on me, but I believe early 360s failing wasn't just widespread; it was straight up most of them dying within the first couple years. It's honestly insane they more or less got away with that. And I guess also speaks to how much Microsoft was killing it in that era that people were willing to go through multiple console RMAs (which I heard was a terrible, slow, and unreliable process) to play 360 games. How far they've fallen.
Simple answer: Halo 3.
It was something like 25% - 50% of all first version 360s died.
Microsoft spent over a billion dollars replacing and repairing consoles to maintain the good brand name of Xbox.
https://en.wikipedia.org/wiki/Xbox_360_technical_problems
Family got first gen 360. Still works to this day. We hit the jackpot with that console. It out lasted 2 wiis and a ps2
Whenever we lost a 360 we got a pre owned 360 from gamestop. I think they went for like $70 for one without any hdd.
That was the real story, by the time they started dying you could just grab a working one for "decently cheap" if you still cared.
However, I wonder how many people got "burned" by it and swore off Xbox consoles going forward.
I know that era we got a lot more use out of the Xbox (original) and the Wii.
Sounds like the 2012(?) Macbook Pro after the switch to leadless solder (?). I had to cook my motherboard 3 times in the oven to revive it.
Funny!
I've heard that flash memory can also be revived with heat, either long duration or high intensity.
https://www.extremetech.com/science/142096-self-healing-self...
Some macbook hacks involved disabling sleepmode, running a benchmark and putting it in a pile of blankets for a few hours
When did the industry transition to different/lead free solders? Wonder if that was part of the issue?
Yeah, it was the transition to RoHS.
> It is interesting that IBM dominated this generation of consoles, and was vanquished in the next.
IBM's Power was the only logical option at the time.
These consoles were being designed around 2000. Intel and AMD weren't partnering on bespoke CPUs at that time. I don't even think AMD would have been considered a viable partner. Neither had viable 64 bit options and part of console marketing at the time was the ever increasing bit depths.
Prior console generations had use MIPS which wasn't keeping up with ever increasing performance expectations and players like Toshiba and Sony were looking for a higher performance CPU architecture. IBM's Power architecture was really the only option. Sony, Toshiba, and IBM partnered to develop their a new 64 bit microarchitecture called Cell.
Microsoft's first console was basically a PC and that's how everyone saw it. The 360 was an opportunity for Microsoft to show that it could compete with the big boys. It was also an opportunity to keep a toe dipped in RISC, because it had dropped support for RISC CPUs with Windows 2000.
By the way, the AMD athlon 64-bit launched 2003. The PS3 launched in 2006. I had an AMD64 bit process in my laptop in 2005.
What wasn't viable?
Yeah that part didn't make sense, not to mention that neither the PS3 nor the 360 were running 64-bit software. They didn't have enough memory for it to be worth it.
Parts of the 360 did. The hypervisor ran in 64bit mode, and use multiple simultaneous mirrors of physical address space with different security properties as part of its security model.
you don't need memory to make 64 bit software worth it. Just 64 bit mathematics requirements. Which basically no video game console uses as from what I understand 32-bit floating point continue to be state of the art in video game simulations
Fundamentally it's still a memory limitation, just in terms of memory latency/cache misses instead of capacity. If you double the size of your numbers you're doubling the space it takes up and all the problems that come with it.
No it isn't. The 64-bit capabilities of modern CPUs have almost nothing to do with memory. The address space is rarely 64 bits of physical address space anyways. A "64-bit" computer doesn't actually have the ability to deal with 64 bits of memory.
If you double the size of numbers, sure it takes up twice the space. If the total size is still less that one page it isn't likely to make a big difference anyways. What really makes a difference is trying to do 64-bit mathematics with 32-bit hardware. This implies some degree of emulation with a series of instructions, whereas a 64-bit CPU could execute that in 1 instruction. That 1 instruction very likely executes in less cycles than a series of other instructions. Otherwise no one would have bothered with it
The original 8087 implemented 80-bit operands in its stack.
It would also process binary-coded decimal integers, as well as floating point.
"The two came up with a revolutionary design with 64 bits of mantissa and 16 bits of exponent for the longest-format real number, with a stack architecture CPU and eight 80-bit stack registers, with a computationally rich instruction set."
https://en.wikipedia.org/wiki/Intel_8087
"Bitness" of a CPU almost always refers to memory addressing.
Now you could build a weird CPU that has "more memory" than it has addressable width (the 8086 is kind of like this with segmentation and 8/16 bit) but if your CPU is 64 bit you're likely not to use anything less than 64 bit math in general (though you can get some tricks with multiple adds of 32 bit numbers packed).
But a 32 bit CPU can do all sorts of things with larger numbers, it's just that moving them around may be more time-consuming. After all, that's basically what MMX and friends are.
I have some confidence that AMD's acquisition of ATI had a huge impact.
That allowed both a CPU and an advanced GPU to be on the same die.
They also wisely sold Global Foundries, and were able to scale with TSMC.
You have to remember that the AMD and Intel of today are very different companies than they were 20-25 years ago. AMD split off it's fab capabilities, acquired ATI, adopted TSMC as a fab, and developed a custom silicon business.
At that time AMD wasn't in the custom CPU business, AMD64 was a new unproven ISA, and x86 based CPUs of that time were notoriously hot for a console. These were also some of the reasons why Microsoft moved away from the Pentium III it had used in the original Xbox.
The PS3 was launched in 2006 but the hardware design was decided years earlier to provide a reference platform for the software.
This article is from 2018.
Previously:
- https://news.ycombinator.com/item?id=16094925
- https://news.ycombinator.com/item?id=27480448
Would need "(2018)" in the title.
unrelated, but recently XBox One was hacked for the first time
https://www.youtube.com/watch?v=FTFn4UZsA5U
How does XBox get hacked when it uses Secure Boot?
Voltage glitching. An outside attacker who has direct, extremely fine-grained control over the power supply to the chip can cause it to brown out for one instruction cycle, preventing a result of an instruction from being written.
With enough sophistication, physical access is more powerful than root access, no exceptions.
Sobre calentamiento