I once met a person that never drank water, only soft drinks. It’s not the unhealthiness of this that disturbed me, but the fact they did it without the requisite paperwork.

Unlike those disorganised people I have a formal waiver. I primarily drink steam and crushed glaciers.

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Cake day: June 14th, 2023

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  • Lawful good: Please don’t use 8P8C for anything other than 10/100/1000BASE* compatible protocols, especially on network devices. It’s confusing.
    Chaotic good: Please don’t use ethernet cable for anything other than ethernet compatible protocols, especially on ethernet devices.
    Lawful evil: That’s a valid use of Cat5 cable.
    Chaotic evil: Let’s talk about RS-485

    True neutral: Wires are just wires and standards are just standards. In a parallel dimensions, somewhere, cat5 is used for 8-phase delta mains power.


  • WaterWaiver@aussie.zoneto3DPrinting@lemmy.worldLines in prints
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    9 months ago

    Sorry for the late reply, tied up. Thankyou for the photos.

    The Z-axis leadscrews look OK in the photos (nothing obviously wrong). That’s a very clean and new printer.

    Q1. Is there any grease on those Z-axis leadscrews (tall metal spiral rods) or are they completely dry?

    Q2. If you force your printer to move up and down does it make unusual noises at some parts of its travel height? You can try typing thing g-code into your printer monitor software to make it move up and down:

    G0 Z100 F1000   (move to Z position 100mm.  You won't actually travel at 1000mm/minute, instead the printer will do whatever it's max is)
    G0 Z0 F1000    (move to Z position 0mm, ie nozzle touching the bed)
    

    You may need to home the axes first (G28)

    Q3. Are these screws on both sides properly tight? I think I might possibly see a gap under one, but it could also be an optical illusion from reflections.




  • SFF = Small Form Factor. It’s smaller than traditional ATX computers but can still take the same RAM, processors and disks. Motherboards and power supplies tend to be nonstandard however. Idle power consumptions are usually very good.

    USFF = Ultra Small Form Factor. Typically a laptop chipset + CPU in a small box with an external power supply. Somewhat comparable with SBCs like Raspberry Pis. Very good idle power consumption, but less powerful than SFF (and/or louder due to smaller cooler) and often don’t have space for standard disks.

    SBC = Single Board Computer.


  • I wouldn’t attack via USB, that path has already been too well thought out. I’d go for an interface with some sort of way to get DMA, such as:

    • PCIE slots including M.2 and external thunderbolt. Some systems might support hotplug and there will surely be some autoloading device drivers that can be abused for DMA (such as a PCIE firewire card?)
    • Laptop docking connectors (I can’t find a public pinout for the one on my Thinkpad, but I assume it’ll have something vulnerable/trusted like PCIE)
    • Firewire (if you’re lucky, way too old to be found now)
    • If you have enough funding: possibly even ones no-one has thought about like displayport + GPU + driver stack. I believe there have been some ethernet interface vulnerabilities previously (or were those just crash/DOS bugs?)

  • I recommend using a different set of flags so you can avoid the buffering problem @[email protected] mentions.

    This next example prevents all of your ram getting uselessly filled up during the wipe (which causes other programs to run slower whenever they need more mem, I notice my web browser lags as a result), allows the progress to actually be accurate (disk write speed instead of RAM write speed) and prevents the horrible hang at the end.

    dd if=/dev/urandom of=/dev/somedisk status=progress oflag=sync bs=128M

    “oflag” means output flag (to do with of=/dev/somedisk). “sync” means sync after every block. I’ve chosen 128M blocks as an arbitrary number, below a certain amount it gets slower (and potentially causes more write cycles on the individual flash cells) but 128MB should be massively more than that and perfectly safe. Bigger numbers will hog more ram to no advantage (and may return the problems we’re trying to avoid).

    If it’s an SSD then I issue TRIM commands after this (“blkdiscard” command), this makes the drive look like zeroes without actually having to write the whole drive again with another dd command.