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I worry that there's a hidden issue with maximum power draw. If the camera supplies less maximum current than the drive could potentially draw from an M.2 slot,
by LarsAlereon 4y ago
I worry that there's a hidden issue with maximum power draw. If the camera supplies less maximum current than the drive could potentially draw from an M.2 slot, you might see the card crash in certain situations. This could be the kind of very annoying thing that works fine in testing but fails in on specific scenario in real-world use.
- wtallis 4y agoIdeally, SSD manufacturers would program their SSD firmware to provide multiple active power states accurately labeled with their maximum power draw, and cameras would select only power states that are within their power delivery constraints. All of this functionality is already defined and standardized. But I'm pretty sure neither side is taking it seriously enough to be relied upon.
- londons_explore 4y agoI think the drive at least will be keeping an eye on its own power rail voltages and logging whenever they sag out of spec. Those logs will be used to rapidly deny your warranty claim when you try to return it for not working properly...
- wtallis 4y agoThe only logs of that sort that I'm aware of is the SMART counter for unexpected power loss. M.2 SSDs are not at all graceful about handling voltage droop, and I don't think I've ever seen one even attempt to automatically lower its power state (and thus peak power draw) in response to low input voltage. They just stop responding, and sometimes require a full power cycle rather than just a reboot. And since the maximum power draw information that SSDs provide to the host is unreliable, you need expensive measurement equipment to determine whether a SSD brown-out is more the fault of the host not providing enough power, or the SSD drawing more power than is reasonable.
- wmf 4y agoAre we talking about the same drives that don't implement flushing properly?