I’m a technical kinda guy, doing technical kinda stuff.

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Joined 9 months ago
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Cake day: September 27th, 2023

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  • The bug is the lack of documentation and that a simple unguarded command can erase all user’s data on the system.

    Also, the principle of least surprise would like a word.

    If I look at the command line arguments of a program called “systemd-tmpfiles” and one of them is called “purge” I will generally assume that option will purge temporary files.

    Now it turns out that someone decided that this program would be a simple way to do something with /home directories(*) so they included /home in the config file for the program, the file that the program reads by default when it is invoked.

    Who decided it would be a good idea for it to deal with /home?

    Wellllll…

    https://github.com/systemd/systemd/blob/main/tmpfiles.d/home.conf

    (*)I have no idea what this program is doing with /home in its config file. I will presume that there is a useful and mostly logical reason for it, and that this command line option was just an unfortunate footgun for those users who were not intimately familiar with systemd.




  • Assumption:

    Someone crams a 300 watt solar panel onto the roof of their EV and manages to integrate it into the charging system so that it’s pretty efficient to use that power.

    Numbers:

    One hour of good sunshine on the 300 watt panel = 300 watt-hours (Wh).

    Average EV energy usage : 200Wh per kilometre these days. Maybe a little more, maybe a little less, depends on how and where you’re driving.

    Result:

    One hour of perfect sunshine hitting the roof of your car equals 1.5 kilometres of extra range, or you can drive your car in a steady-state fashion at a 3-5 kilometres per hour because an EV is more efficient than the average usage at lower speeds.

    Conclusion:

    Probably better off increasing the storage capacity of the battery as a full day’s sunshine will get you about 10 kilometres of range.


  • I hate how bloated the kernel is. I’d like it to fit into main memory.

    Take a copy of lspci, lsusb. Use them to build a kernel from source with only the bits you need and then make the bits you might need modules. Include your filesystem driver into the kernel and you can skip the usual initramfs stage and jump straight to your root filesystem.

    Might take a few tries, but at least it doesn’t take 18 hours to compile the kernel anymore…


  • You need silicon.

    The earth’s crust is about 25 percent silicon. Sand made out of quartz like desert sand is about 50 percent silicon. Beach sand is usually mainly calcium carbonate from shells and it doesn’t contain much silicon at all. Volcanic beach sand is more likely the same as the earth’s crust so 25-50 percent.

    So as long as you refine your sand/gravel/rocks/lava so that you’re left with pretty much pure silicon, you’re good to go.








  • LIVE BLACKBIRDS???

    Sing a song of sixpence a pocket full of rye,

    Four and twenty blackbirds baked in a pie.

    When the pie was opened the birds began to sing,

    Oh wasn’t that a dainty dish to set before the king?

    The king was in his counting house counting out his money,

    The queen was in the parlour eating bread and honey

    The maid was in the garden hanging out the clothes,

    When down came a blackbird and pecked off her nose!

    Moral of the story, don’t be a minor character in an 18th century nursery rhyme.



  • Yes, I shifted to my own domain after my default ISP of 20 years decided that email was just too hard, you know? They didn’t outright say it, they just started batch processing emails so that I’d get all my daily emails at around 2 am the next day. Super handy for time limited password reset emails!

    A few hours reading a guide and setting up a $5/mo linode email server with SPF and dmarc, a few more hours transferring 20 years of IMAP mail from my old account to a folder, and a month or so of changing a few site contact emails over each day when they emailed something to my old account, and now I’ve got an email server on my own domain that is 10 times faster at sending/receiving mail than my old ISP ever was.

    And now I can have amazon@mydomain.com and career@mydomain.com and random other disposable addresses so that when they are inevitably sold off for the $$$ I can just dump them and maintain a spam free inbox.


  • You’re thinking of a firewall. NAT is just the thing that makes a connection appear to come from…

    That connection only “appears to come from” if I explicitly put a rule in my NAT table directing it to my computer behind the router doing the NAT-ing.

    Otherwise all connections through NAT are started from internal->external network requests and the state table in NAT keeps track of which internal IP is talking to which external IP and directs traffic as necessary.

    So OP is correct, it does apply a measure of security. Port scanning someone behind NAT isn’t possible, you just end up port scanning their crappy NAT router provided by their ISP unless they have specifically opened up some ports and directed them to their internal IP address.

    Compare this to IPV6 where you get a slice of the public address space to place your devices in and they are all directly addressable. In that case your crappy ISP router also is a “proper” firewall. Strangely enough it usually is a “stateful” firewall with default deny-all rules that tracks network connections and looks and performs almost exactly like the NAT version, just without address translation.



  • Flash chip cells are basically tiny electron traps, they consist of a tiny stored charge surrounded on all sides by an insulator. When writing to the cell you fill it with some electrons via (much handwaving here) a method of quantum tunneling. You can then read the cell by sensing the internal charge without disturbing it.

    When not in use eventually enough charge tunnels out of the cell via random quantum tunneling events for it to read nothing. This is worsened when things are hotter, so maybe keeping your flash chips in the freezer would help.

    Consumer flash memory, I probably wouldn’t expect more than 20 or 30 years of offline storage out of it. The older chips would last longer, because their cells are bigger, and you’re not trying to read multiple charge levels per cell like the newer stuff.

    Added edit:

    Magnetic media probably has a higher chance of surviving longer. Floppies from the 80s can still be read, for example, but they are low density media. You’d want something that separates the drive system from the actual magnetic media to stop bearing or motor failure from being an issue , so tape would be a good idea.

    The problem is, of course, that you could end up with media you can’t read as nobody makes the hardware for it. Tape drives have gone through a dozen revisions in the last 30 years as capacity has increased, but as long as you have the same physical tape cartridge you should be ok.

    M-Disc is a blueray compatible media that doesn’t use dye and should have a life of hundreds of years. But who will have a blueray reader on hand in the 24th century? I’ve got a USB M-Disc compatible writer for my backups, but in 30 years will I be able to pull it out of a drawer and plug it into a USB Gen 15 port and have it work with whatever software I have then?

    I think we’re going to have to do the manual duplication process for a while yet, until we finally settle on some universal petabyte storage crystals or something.