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Cake day: June 18th, 2023

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  • mkwt@lemmy.worldtoTechnology@lemmy.world*Permanently Deleted*
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    2 months ago

    802.11ax, clients just… (essentially) wait for a random amount of time, listen for a break in the signal, and take a leap of faith.

    Ethernet originally worked the same way, back when it competed directly against token ring. Ethernet won by being as reliable in real world scenarios while being cheaper to build out. Gigabit Ethernet was the first standard that insisted on full duplex only.

    Half duplex mode with the collision avoidance is still actively supported for 10/100, but it is becoming very hard to find an unswitched hub. So you may have to write up your own twisted pair cables.





  • mkwt@lemmy.worldtoMemes@lemmy.mlEnd Monopoly & Restart
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    2 months ago

    Most games I’ve seen, nobody ever horse trades for color groups.

    Complex deals and negotiations, land swaps, leveraged buyouts, and free rent passes, are all supposed to be part of the game. Getting a color group solely by landing on the spaces first and buying them for list price is indeed rare, by design.

    This leads to my other pet peeve… You’re not supposed to have enough money to go around the board the first time and buy every space you land on at the list price. You’re supposed to be forced to make strategic decisions from the beginning of the game about what you go for, and what you bid in the auctions.

    Most of the made up “house rules” are really about circulating more money into the game than is supposed to be there.


  • You should also know that because of jail and various other teleports, the orange group is the most popular group on the board. It’s something like 1.8 times the average to land on those spaces, because two of them are 6 and 8 spaces from jail. Jail is a very popular space because Go To Jail also counts as Jail.

    Boardwalk has very high rents, but it’s also pretty unpopular to land on.

    The worst rent-to-popularity values are yellow and green.


  • Here’s my guess. I don’t know anything about this particular device, but I have worked with medical devices.

    A powered exo-skeleton sounds like it might be a class II medical device. Being a medical device, the OEM was required to produce a safety risk analysis per ISO 14971 in the EU and 21 CFR 820 in the US. I don’t know what all was listed, but probably one of the safety risks was thermal runaway from the (assumed) lithium ion batteries.

    Lithium ion battery packs have a well known problem with occasionally overheating and catching fire. This famously delayed the launch of the 787 Dreamliner. This is also why you can’t put your phone or laptop battery into your checked luggage.

    In the original risk analysis, there will be a number of mitigation steps identified for each hazard. For the lithium thermal runway, these probably include a mix of temperature monitoring, overheat shutdown, and passive design features in the battery pack itself to try to keep the impacts of over temperature and fire away from the patient.

    So how does the price get to 100k? It could be some kind of unique design features that are now out of production and the original tooling is not available. The 100k cost is probably something like to redesign the production tooling, particularly if you have to remake injection molds.

    You can’t just use any off the shelf battery pack, because that would invalidate the risk analysis. You’d need to redo the risk analysis, repeat at least some amount of validation testing, and possibly resubmit an application to the FDA.

    TLDR: you can get some MEs and EEs together to solve this problem, but once they’re on the case, you can blow through 100k real fast.



  • Medical devices are required to comply with 21 CFR 820 in the United States, which establishes quality management standards. This includes minimum standards for the software development lifecycle, including software verification and validation testing.

    In the EU, broadly equivalent standards include ISO 13485 and IEC 62304.

    If an OEM wants to do a software update, they at minimum need to perform and document a change impact analysis, verification testing, and regression testing. Bigger changes can involve a new FDA submission process.

    If you go around hacking new software features into your medical device, you are almost certainly not doing all of that stuff. That doesn’t mean that your software changes are low quality–maybe, maybe not. But it would be completely unfair to hold your device to the standard that the FDA holds them to–that medical devices in the United States are safe and effective treatments for diseases.

    This may be okay if you want to hack your own CPAP (usually a class II device) and never sell it to someone else. But I think we all need to acknowledge that there are some serious risks here.



  • I thought they catch fire and burn down slowly.

    Correct. Both the recent pager and radio attacks, and the 1996 cell phone attack, were performed by planting military explosives inside the devices in advance.

    There is no magical way to hack the electronics to make a lithium battery straight up explode.