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Finding a CPU Design Bug in the Xbox 360 (2018)
- jszymborski 7mo agoWould need "(2018)" in the title.
- chasil 7mo agoIt 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 https://en.wikipedia.org/wiki/Xbox_360_technical_problems
- vondur 7mo agoI 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.
- chasil 7mo agoThe 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."
- thenthenthen 7mo agoSounds 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.
- chasil 7mo agoFunny! 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-heating-flash-memory-survives-more-than-100-million-cycles https://www.extremetech.com/science/142096-self-healing-self...
- thenthenthen 7mo agoSome macbook hacks involved disabling sleepmode, running a benchmark and putting it in a pile of blankets for a few hours
- timw4mail 7mo agoAnd there was the same problem with early PS3s, on Nvidia's GPU package...it was a fairly widespread problem at the time.
- rwmj 7mo agoAnd Apple iBook G3s too. There's a whole thing with owners reflowing the GPU: https://www.instructables.com/Fixing-the-infamous-iBook-screen-problem/ https://www.instructables.com/Fixing-the-infamous-iBook-scre...
- keyringlight 7mo agoI seem to recall baking PC nvidia GPU boards in your oven was a reasonably common out-of-warranty fix around that era.
- Moosdijk 7mo agoI 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.
- rangestransform 7mo agoIIRC this is to do with the phase in of RoHS and bad lead free solder
- hbn 7mo agoI 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.
- rustystump 7mo ago
- esaym 7mo agoWhen did the industry transition to different/lead free solders? Wonder if that was part of the issue?
- monocasa 7mo agoYeah, it was the transition to RoHS.
- cptskippy 7mo ago> 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.
- Grazester 7mo agoBy 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?
- Narishma 7mo agoYeah 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.
- sidewndr46 7mo agoyou 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
- duped 7mo ago
- hrmtst93837 7mo ago[flagged]
- brucedawson 7mo agoIt did not help that the performance of the Xbox 360 CPU (and Cell) was terrible. In-order execution without the crazy-high frequencies the CPU was designed for was a failure.
- TazeTSchnitzel 7mo agoThis article is from 2018. Previously: - https://news.ycombinator.com/item?id=16094925 https://news.ycombinator.com/item?id=16094925 - https://news.ycombinator.com/item?id=27480448 https://news.ycombinator.com/item?id=27480448
- NooneAtAll3 7mo agounrelated, but recently XBox One was hacked for the first time https://www.youtube.com/watch?v=FTFn4UZsA5U https://www.youtube.com/watch?v=FTFn4UZsA5U
- brcmthrowaway 7mo agoHow does XBox get hacked when it uses Secure Boot?
- Tuna-Fish 7mo agoVoltage 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.
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- alumno_007 7mo agoSobre calentamiento
- dev-ns8 7mo agoWow... 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?
- cumshitpiss 7mo ago[dead]
- brucedawson 7mo agoAuthor here: This is not a common problem. I think I was told that Alpha had basically the same bug but it is a bug, for sure. Speculative execution causing problematic side effects is a deal killer. Speculative execution, however, can cause less problematic side effects. For instance, a speculatively executed load or prefetch will usually actually prefetch which will pollute the cache, TLB, etc., and reveal side-band information, but that is a performance problem and perhaps a subtle security flaw, not a correctness bug like this was.
- MBCook 7mo agoI remember reading this many years ago, it was great. In the last week Raymond Chen on his The Old New Thing mentioned the concept of delay slots on some CPUs. It sounds like a similar thing, just formalized so it’s not a bug. Knowing that the instruction after a branch always executes, regardless of if the branch is taken. Do I have that right?
- brucedawson 7mo agoI think that is correct, but yes, a delay-slot instruction that is always executed is easy to reason about. Speculative execution that gets real? shudder
- MBCook 7mo ago