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posted by martyb on Sunday August 30 2020, @01:32PM   Printer-friendly
from the of-course-it-is-impossible-to-get-online-using-a-desktop dept.

US Laptop Shortage Could Derail Remote Learning:

As students and teachers prepare for a return to in-person learning for at least some of the time this fall, many of the nation's schools are facing shortages and delays for laptops and tablets needed for online learning, an Associated Press investigation revealed.

Lenovo, HP and Dell, the nation's largest computer companies, have informed school districts that they are short nearly five million laptops.

[...] Last month, at the request of President Donald Trump, the U.S. Department of Commerce imposed sanctions on 11 Chinese companies, including Lenovo, AP reported. School administrators have asked the Trump administration to devise a solution because remote learning without laptops is impossible.

Lenovo has informed school districts of the supply chain delays and the trade controls set by the Commerce Department, which would cause another slowdown. Lenovo declined to respond to an inquiry from AP.

Have any Soylentils run into this?


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  • (Score: 2) by RS3 on Monday August 31 2020, @05:22AM (4 children)

    by RS3 (6367) on Monday August 31 2020, @05:22AM (#1044489)

    Okay, here's my solution for you. Are you ready? :) Besides lots of ground rods and well-connected surge suppressors, cut the coax cable far from the house. Build a small doghouse to house the cable modem (gateway) in the box. At the Ethernet (LAN) jack attach a fiber media converter, and run fiber to the house.

    To power the cable modem and media converter- either solar panels and batteries, or a long flexible fiberglass shaft in a plastic (PVC) sheath and a motor-generator pair. It's only maybe 10-20 watts load so it's not too much. Or instead of the flexible shaft you could use pulleys and a long rope.

    Okay, I admit I'm cracking myself up but it could work.

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  • (Score: 2) by JoeMerchant on Monday August 31 2020, @12:05PM (3 children)

    by JoeMerchant (3937) on Monday August 31 2020, @12:05PM (#1044549)

    What you're suggesting might work, and then the lightning might decide to enter via some other route. We have friends who know someone who had lightning boil the water in their pipes, bursting them all over the house. I'm wondering if our metal roof might become a giant capacitor plate and couple energy into all kinds of other metal objects in the house even if they are air-gaped. It's kind of a classic adversarial problem: the common entry point used to be mains powerlines, but mitigations on the mains have finally reached a point where it's something else - not surprising that something else is the cable company TBH.

    I've got 12 gauge landscape lighting around the yard, so that's a mesh of conductors ready to channel energy back into the garage - it seems that the AC-DC converter survived the hit, but the GFCI outlet that supplied it was destroyed - not once, but twice. I replaced it and that second strike took out the garage GFCI again, and instead of just tripping the in-house GFCI, it was also permanently damaged by the 2nd strike. Could be the landscape lighting, or - more likely I think - it could have been the robot lawnmower's perimeter wire. Luckily, I suppose, I did not get the mower repair parts until after the 2nd strike hit, so I didn't end up having to repair the mower twice. Just the thought of a ring of copper around the entire yard gives me shivers when I think about lightning striking _inside_ that loop. Not sure how the timeline went, but my final mower repair (after replacing the burnt-out loopwire sensor board) was in the loop wire itself - it just physically snapped, no burn marks or anything, just broke like someone cut it underground.

    --
    🌻🌻 [google.com]
    • (Score: 2) by RS3 on Tuesday September 01 2020, @12:49AM (2 children)

      by RS3 (6367) on Tuesday September 01 2020, @12:49AM (#1044778)

      I ASSume your metal roof is well grounded??? Actually it should give you a lot of protection by being a capacitor plate- it would greatly dampen out the peak voltage. But if it's properly grounded at many points to good ground rods, you should be quite well protected.

      And you have some really good lightening rods?????

      The theory is that the lightening rod shorts out atmospheric "static" charges that can develop on and around houses and trees and "attract" lightening. If you've ever played with high voltage stuff (and who hasn't) you'll know about "corona discharge" and how sharp points seem to be a better conductor (inducer?) of charge into and out of atmosphere. So get some pointy rods up there if you haven't already. And they really need to be grounded- a lot! You may need 10 ground rods. Can one really have too many? The copper-clad ones are better than galvanized. One would get rid of any accumulating charge, but would not absorb much of a direct strike. I know you said you have at least 1 ground rod.

      You probably know that depending on soil and grounding requirements, in some (many) installations standard ground rods are ineffective and we go to much larger diameter (and maybe length) rods. In the really serious situations a borehole is drilled, very long rod dropped in, and then conductive "stuff" poured in. It's all about conductive surface area in contact with earth (unconsolidated overburden. :) My dad used to talk about "watering" ground rods. Don't know for sure but I'd imagine in some locations an irrigation system might be called for.

      As you probably know, if lightning strikes one of your trees, there will be a large voltage gradient in the ground for a large distance around the tree. So your landscape wires and mower perimeter (robot mower- very cool!!) wire are just big energy gatherers. And these energy spikes are unpredictable- they propagate like RF energy and it's very difficult to predict their paths. No surprise at all that your GFCIs are getting hammered.

      I have to do some thinking about some solutions, like wireless direction system for the mower (maybe GPS or 2 WiFi antennas and some interesting triangulation algorithm). And if your landscape lights are LED, you could probably run them from a battery that could have solar charging, and easily swapped for a battery being charged in the house. Anything to get away from having wires coming into your house, other than AC mains. And as I mentioned above, you could get a big isolation transformer for more protection. Or not a huge one, but just isolate some circuits like computer, TV, etc. And real surge suppressors- big ones. I'll design you one- point is one with several big MOVs, fast-acting fuses, maybe some low-value series resistors to limit spikes. Think of a ladder using resistors for the sides and MOVs as the rungs. That way if the first MOV blows up, you'll have 2nd, 3rd, etc. Maybe such things are on the market- haven't searched.

      If you know anything about RF and antennas, you'll know those conductive rods can have 0 volts at one end, and theoretical huge voltage at the other end, if they're in proper resonance / tuning. Your perimeter wire just happened to have a resonance peak where the wire popped- huge current at that point. Would've been cool to see some kind of waveform of the whole event, along the wire. Not willing to sacrifice my precious oscilloscopes to try it though!

      • (Score: 3, Interesting) by JoeMerchant on Tuesday September 01 2020, @01:28AM (1 child)

        by JoeMerchant (3937) on Tuesday September 01 2020, @01:28AM (#1044788)

        And you have some really good lightening rods?????

        Apparently, that would be the trees. There's about a dozen left in the vicinity that should shield the house as well as the last one did.

        I ASSume your metal roof is well grounded???

        Not really, if it were it might become the strike point instead of the trees - I'm pretty sure I don't want to draw lightning toward a 60 year old wooden structure. In that same storm that fragged my tree, a neighbor's pickup truck was struck, caught on fire on the inside - burned to a crisp.

        I've wanted to engineer my own robot mower forever, I have the skills to do it a dozen different ways, I even have sufficient capital to build prototypes and maybe start small scale production if I can market it, what I lack is the time - damn day job with fat salary and benefits, making us all wage slaves aren't they? In the meantime, the perimeter wire solution is actually very practical from a safety and cost standpoint - even if I did engineer my own mower with some optical flow guidance, I'd probably end up using the perimeter wire for series production (liability concerns about runaway cutting equipment), and also to cut the cost and maintenance in half by dropping the video processing bits.

        No surprise at all that your GFCIs are getting hammered.

        I said "zero damage" for the second strike, but that doesn't count the $70 worth of GFCIs that I had to replace after it.

        Would've been cool to see some kind of waveform of the whole event, along the wire. Not willing to sacrifice my precious oscilloscopes to try it though!

        Was kind of interesting learning to use the wire break tracer tool - it only had about 500' of effective break-finding range, but I've got about 3000' of perimeter wire, so after I decided that there was no break within 500' in either direction of the base station I basically moved 800' down one leg, cut the wire there, and traced from that point - 500' further: nothing, 40' back I found the break, so just ran a replacement wire 40' from the break to the cut that I made, which happened to be the 40' closest to the lightning strike tree also... still didn't find any burn marks on the insulation, kind of a letdown after the scorching on the ethernet sockets.

        --
        🌻🌻 [google.com]
        • (Score: 2) by RS3 on Tuesday September 01 2020, @07:41PM

          by RS3 (6367) on Tuesday September 01 2020, @07:41PM (#1045052)

          I didn't think about the wire being that long but it makes sense. TDR? (Time-Domain Reflectometer)

          I'm not so sure about your ungrounded metal roof philosophy... Have you studied, and consulted experts? Again, the theory is a charge develops around objects and attracts the lightning discharge. The pointed rods drain off that charge and the lightning hits somewhere else. People have put lightning rods in trees too.

          I said "zero damage" for the second strike, ...

          Yeah, I got that. There's almost nothing predictable nor deterministic about surges, lightning strikes, and the resulting damages. We just do our best to mitigate and hope...

          I'd have to look into getting rid of the copper surge collectors (various wires).

          Regardless, your story inspires me to count my blessings. The old "I complained because my foot hurt, then I met a man without a foot."