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Comment by dsl | Hacker News Reader

It's 1 GB/sec of data from sensors. Likely processed, but not stored.

To get 1 GB/sec write throughput in a moving car you would need to be using some form of solid state storage, which would be pretty darn pricey over an hour test drive.

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It's likely far cheaper to store it than it would be to run the test again. This is Google, they can certainly afford it – I'd be incredibly surprised if they weren't storing it.

Having developed autonomous vehicles in a previous career, I can tell you that raw sensor data is far less useful than you think. By the time you are starting to hand over controls to the system itself you are pretty damn confident that your pipeline up to the control logic is all very solid.

Also, i'm not entirely sure what you think the costs involved in a test are? We purchased about 20 acres of land for a test track, but that was the only real expense involved in day to day development.

The true data rates (see my other posts) are most likely around 5-10 MB/s. Which is so low the benefits out weigh the costs. After all, what if their is an issue with the software? How are you going to reproduce without the logs, especially on a R&D system like Google has (yes it's still R&D, they can't even drive in the rain).

Your "true data rate" is completely wrong. You have no idea at what frequency they are converting analog to digital signals. You don't know for sure they are using off the shelf sensors. Your ignoring data sources in your calculations like OBD from the ECU or even GPS and AGPS data. etc etc.

You only need to store the data until you can upload it, which might not be that long if the car has an internet connection. Furthermore I assume not all parts of that data is equally valuable. If this is raw data coming from sensors I think it is fair to assume that a significant part is noise that can be discarded.

So I would assume that even though you are probably unable to store 1GB/s of data - today at least - you might still be able to store the interesting parts and use those.

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