Finding a CPU Design Bug in the Xbox 360 (2018)

4 days ago (randomascii.wordpress.com)

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."

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  • > 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.

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.