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The Truth About Last Year's Xbox 360 Recall
chrplace forwards an article in which Gartner's Brian Lewis offers his perspective on what led to last year's Xbox 360 recall. Lewis says it happened because Microsoft wanted to avoid an ASIC vendor. "Microsoft designed the graphic chip on its own, cut a traditional ASIC vendor out of the process, and went straight to Taiwan Semiconductor Manufacturing Co. Ltd., he explained. But in the end, by going cheap — hoping to save tens of millions of dollars in ASIC design costs, Microsoft ended up paying more than $1 billion for its Xbox 360 recall. To fix the problem, Microsoft went back to an unnamed ASIC vendor based in the United States and redesigned the chip, Lewis added. (Based on a previous report, the ASIC vendor is most likely the former ATI Technologies, now part of AMD.)"
I am a person that designs both hardware, and software, but not chips, At the risk of talking outside of my expertise, I will have a go at answering your question.
Firstly, there are things that software people really like, but it is often better to not do them in hardware. This category contains things like Read/Write I/O registers. From a software point of view, they are nice, but they can double your gate count. They can also increase your capacitive bus loading. DAC and ADC designs can also be affected this way. A software person might use a proper ADC and expect proper ADC registered results. A hardware person might select a resistor, capacitor, a voltage comparitor, and a couple of spare I/O pins. The cheesy R/C approach may save the hardware design from a whole slew of problems including cost. A software person may opt for a synchronous logic approach with all registers clocked every clock cycle. The hardware designer may opt for a much more asynchronous approach, that minimizes the number of clocked registers. This reduces power consumption, and potentially the number of registers too. Often the hardware designer will consider thermal, cost, electrical layout issues as part of his design process. The software person will not be as familiar with how to design a good circuit board and chip design in a cost-effective manner. A good software engineer can learn all of this material with time, but the hardware engineers will do them naturally.
The second category of problems is tools. The modern chip designer is working with a fairly advanced set of tools that the software person is likely to be quite unfamiliar with. This starts with the IC design tools, which are quite specialized. It ends with the hardware engineering tools. Have you ever X-Rayed a circuit board to analyze the cracks in the Ball Grid Array where it bonds to the circuit board? Are you familiar with thermal issues, and thermal images? How about EMI test results? Modern IC package design limitations? A good team of engineers will be familiar with these tools, and know how to use them to get good results.
The third category of problems is mistakes from inexperience, or lack of experience in the correct field. I work with industrial electronics. I think from an industrial point of view. What happens when someone attaches 600 (VAC) to the ground wire of the computer? What happens to the remote sensors when the plant gets hit by lightening? In IC design, there are some known gray areas too. Does the chip reset properly on power up? Do metastable, astable, or self-oscillating states exist in the IC design? Can the chip survive with no cooling? Does the chip have an overtemp shutdown function? What happens if someone starts the chip up in sub-zero weather? Do the analog electronics have sufficient electrical separation from the digital electronics, while avoiding nasty things like ESD latchup conditions?
I've completed chip design courses before, but have never had to design a modern production gate array design. As a person that has done both software and hardware, I know that my skills are not good enough for the most modern IC design processes. My limit is FPGA work, and my preference is clever opto-isolation, power semiconductor, TTL and micro-proccessor based circuits. In analog, my expertise in analog is industrial sensing and survivability. You have to know where your field of expertise is, and what your limits are.
Anyone else think it funny that the guy that played Ballmer in that Pirates of Silicone Valley movie is the guy that does the voice for Bender?