5 ms·

Windows won’t have enough logical resources even they did away with IRQs and stuff. I’ve run into this at around a dozen USB devices—got to find the article on

Windows won’t have enough logical resources even they did away with IRQs and stuff. I’ve run into this at around a dozen USB devices—got to find the article on this.

tumblewit 6y ago
macOS doesn't even support beyond 15 ports. And USB 3.0 counts as 2 ports due to backward compatibility.
- sgt 6y ago
  Surely that's possible to do using hubs?
  - hrrsn 6y ago
    It's a 15 port per controller limit. USB hubs are fine. https://dortania.github.io/OpenCore-Post-Install/usb/#macos-and-the-15-port-limit https://dortania.github.io/OpenCore-Post-Install/usb/#macos-...
noizejoy 6y ago
Not sure, if your experience is more dictated by USB hub limitations, rather than hitting a Windows limit that soon. Here’s an interesting page describing how to best get to high USB device counts[0] [0] https://www.yoctopuce.com/EN/article/how-many-usb-devices-can-you-connect https://www.yoctopuce.com/EN/article/how-many-usb-devices-ca...
FpUser 6y ago
I have more than 20 devices connected, no problems. Using hubs though.
- rrreese 6y ago
  Yes I also have more then 12 right now, so its a little odd.
- coldtea 6y ago
  Running all as USB3 though? Very few peripherals have USB3 level inputs...
  - FpUser 6y ago
    Hard drives are all USB3. The rest is either.
- ddlsmurf 6y ago
  May I ask which 20 devices ? I'm having trouble imagining more than say 5
  - yellowapple 6y ago
    I can definitely see this happening if you need to run a farm of printers (be they of the 2D or 3D variety) and Ethernet ain't an option. I don't know of any such printers that can even use USB3, though (let alone require it), but still. Indeed, a buddy of mine has at least 6 or so going at once for his 3D printing business, and we're considering a similar sort of strategy (w/ e.g. some box running Slic3r and Octoprint) so he ain't constantly running USB sticks back and forth.
    - ddlsmurf 6y ago
      That's a pretty bad idea, the usb virtual serial port used by most 3d printers, because of it's low throughput, can worsen print quality, it's is much better to just upload to the sd via octoprint. For 2d printers I haven't seen any without network connectivity in a decade, and I can't imagine anyone needs 20 2d printers that are so old or cheap they don't network.
      - yellowapple 6y ago
        > it's is much better to just upload to the sd via octoprint That's... pretty much exactly the plan, yes. The printers we're using all (to my knowledge) run some version of Marlin w/ SD support, so we'd be doing this via the M28/M29 GCode commands over that same USB interface. It ain't clear that OctoPrint supports this directly, but as long as it's able to shove the exact GCode we tell it to shove we should be able to make that happen. Since Marlin's supposed to wait until it gets an M29 command before it starts printing, it seems to me like low throughput would therefore be a non-issue (aside from, you know, the amount of time it'd take to push that data across, but that'd really only be an issue for the first time we're printing a new file).
  - FpUser 6y ago
    >"I'm having trouble imagining more than say 5" That's ok. People have different needs. For me it is mostly many hard drives, exercise equipment, multiple cameras, some stuff I am testing and lots of smaller things.
- rbinv 6y ago
  I'm curious: what kind of devices? Seems like a lot.
  - karma_fountain 6y ago
    Maybe USB 3g dongles for running a click farm?
    - FpUser 6y ago
      Are you reflecting on your own experience?
  - pcdoodle 6y ago
    Cameras, Sensors, Barcode, Scales, Etc.
ytch 6y ago
But in the book "How We Test Software at Microsoft", they mentions Microsoft test USB implementation with "USB Cart of Death", which including 10 of 8 port usb hub: https://books.google.com.tw/books?id=X5lCAwAAQBAJ&pg=PT414&lpg=PT414&dq=%22USB+Cart+of+Death%22&source=bl&ots=v0qBrqEGpY&sig=ACfU3U1shLj1hod6ohurBzXNjoWMl6anoQ&hl=zh-TW&sa=X&ved=2ahUKEwjYm5b51_nrAhX_w4sBHT5uDxYQ6AEwAnoECAEQAQ#v=onepage&q=%22USB%20Cart%20of%20Death%22&f=false https://books.google.com.tw/books?id=X5lCAwAAQBAJ&pg=PT414&l... Edit: Maybe it is no issue with USB hub, but not work with too many usb controller (USB port to MB directly)?
bsder 6y ago
This is unlikely for USB 2.0 and up. It might be true if you have old devices, though. If you have USB 1.0/1.1 full speed HID devices you can overcommit the available bandwidth for a human interface device. HID devices generally require that they be serviced every 1ms with a 64 byte packet. You might overrun that if you put enough old devices together on an old hub. It's quite unlikely for USB 2.0+ with anything High Speed. The only issue with new devices is that USB 3.0+ requires twice the endpoints of USB 2.0. The problem is that the Intel controller chips allocate the same amount of memory for USB 3.0 as they do USB 2.0. So if you have a system with a lot of devices (96+), you can hit the memory limit of the controller. We hit that limit with a 192 device system. It took a while to figure out what the heck was wrong.

Windows won’t have enough logical resources even they did away with IRQs and stuff. I’ve run into this at around a dozen USB devices—got to find the article on this.

tumblewit 6y ago

macOS doesn't even support beyond 15 ports. And USB 3.0 counts as 2 ports due to backward compatibility.

sgt 6y ago
Surely that's possible to do using hubs?
- hrrsn 6y ago
  It's a 15 port per controller limit. USB hubs are fine. https://dortania.github.io/OpenCore-Post-Install/usb/#macos-and-the-15-port-limit https://dortania.github.io/OpenCore-Post-Install/usb/#macos-...

noizejoy 6y ago

Not sure, if your experience is more dictated by USB hub limitations, rather than hitting a Windows limit that soon. Here’s an interesting page describing how to best get to high USB device counts[0] [0] https://www.yoctopuce.com/EN/article/how-many-usb-devices-can-you-connect https://www.yoctopuce.com/EN/article/how-many-usb-devices-ca...

FpUser 6y ago

I have more than 20 devices connected, no problems. Using hubs though.

rrreese 6y ago
Yes I also have more then 12 right now, so its a little odd.
coldtea 6y ago
Running all as USB3 though? Very few peripherals have USB3 level inputs...
- FpUser 6y ago
  Hard drives are all USB3. The rest is either.
ddlsmurf 6y ago
May I ask which 20 devices ? I'm having trouble imagining more than say 5
- yellowapple 6y ago
  I can definitely see this happening if you need to run a farm of printers (be they of the 2D or 3D variety) and Ethernet ain't an option. I don't know of any such printers that can even use USB3, though (let alone require it), but still. Indeed, a buddy of mine has at least 6 or so going at once for his 3D printing business, and we're considering a similar sort of strategy (w/ e.g. some box running Slic3r and Octoprint) so he ain't constantly running USB sticks back and forth.
  - ddlsmurf 6y ago
    That's a pretty bad idea, the usb virtual serial port used by most 3d printers, because of it's low throughput, can worsen print quality, it's is much better to just upload to the sd via octoprint. For 2d printers I haven't seen any without network connectivity in a decade, and I can't imagine anyone needs 20 2d printers that are so old or cheap they don't network.
    - yellowapple 6y ago
      > it's is much better to just upload to the sd via octoprint That's... pretty much exactly the plan, yes. The printers we're using all (to my knowledge) run some version of Marlin w/ SD support, so we'd be doing this via the M28/M29 GCode commands over that same USB interface. It ain't clear that OctoPrint supports this directly, but as long as it's able to shove the exact GCode we tell it to shove we should be able to make that happen. Since Marlin's supposed to wait until it gets an M29 command before it starts printing, it seems to me like low throughput would therefore be a non-issue (aside from, you know, the amount of time it'd take to push that data across, but that'd really only be an issue for the first time we're printing a new file).
- FpUser 6y ago
  >"I'm having trouble imagining more than say 5" That's ok. People have different needs. For me it is mostly many hard drives, exercise equipment, multiple cameras, some stuff I am testing and lots of smaller things.
rbinv 6y ago
I'm curious: what kind of devices? Seems like a lot.
- karma_fountain 6y ago
  Maybe USB 3g dongles for running a click farm?
  - FpUser 6y ago
    Are you reflecting on your own experience?
- pcdoodle 6y ago
  Cameras, Sensors, Barcode, Scales, Etc.

ytch 6y ago

But in the book "How We Test Software at Microsoft", they mentions Microsoft test USB implementation with "USB Cart of Death", which including 10 of 8 port usb hub: https://books.google.com.tw/books?id=X5lCAwAAQBAJ&pg=PT414&lpg=PT414&dq=%22USB+Cart+of+Death%22&source=bl&ots=v0qBrqEGpY&sig=ACfU3U1shLj1hod6ohurBzXNjoWMl6anoQ&hl=zh-TW&sa=X&ved=2ahUKEwjYm5b51_nrAhX_w4sBHT5uDxYQ6AEwAnoECAEQAQ#v=onepage&q=%22USB%20Cart%20of%20Death%22&f=false https://books.google.com.tw/books?id=X5lCAwAAQBAJ&pg=PT414&l... Edit: Maybe it is no issue with USB hub, but not work with too many usb controller (USB port to MB directly)?

bsder 6y ago

This is unlikely for USB 2.0 and up. It might be true if you have old devices, though. If you have USB 1.0/1.1 full speed HID devices you can overcommit the available bandwidth for a human interface device. HID devices generally require that they be serviced every 1ms with a 64 byte packet. You might overrun that if you put enough old devices together on an old hub. It's quite unlikely for USB 2.0+ with anything High Speed. The only issue with new devices is that USB 3.0+ requires twice the endpoints of USB 2.0. The problem is that the Intel controller chips allocate the same amount of memory for USB 3.0 as they do USB 2.0. So if you have a system with a lot of devices (96+), you can hit the memory limit of the controller. We hit that limit with a 192 device system. It took a while to figure out what the heck was wrong.