Wikipedia:Reference desk/Archives/Computing/2016 December 17
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December 17 edit
USB Hub understanding problem edit
Following this post:
I’ve planned on to buy two of [1], I might not receive the power plug:
1.1) I wish to use all 32 ports in the near future, will I face any problems such as “power loss”…? Also, what other problems could I face on top/along/rather than what’s enquoted?
1.2) I'm unable to find the full specification for the selected 'hub to buy' link could someone help me please? - I would like to know the per port output...
2) What is the best solution? I wish to buy two hubs only because I have two USB v3.0 ports on the right-hand-side of my Laptop. - Is this a little brat-kid move? I mean, I’ll definitely use’em all if I get a chance to add extra rubbish with my Laptop, as time passes by...
3) If it's possible, please send me a link with a UK power plug, for to buy...
103.230.104.12 (talk) 19:47, 17 December 2016 (UTC)
- That hub comes with a 5v 5-amp power adaptor which should be adequate to run all sixteen ports provided you are not drawing a large current on several of them. I can't guarantee this, but my guess would be that each port might supply up to 2 amps if required, but the specification is for only 0.9 amps so it is possible that there is some limiting circuitry. For example, it would not be wise to charge three iPads from one hub since each might draw more than two amps, overloading the power supply and wiring. I'm having difficulty imagining what you are going to plug in to all 32 ports, but perhaps there are some devices that I've never heard of. Perhaps an expert on USB technology will know if using 32 ports simultaneously will cause a significant delay or slowing in the communications? I don't know enough about the protocols. Dbfirs 20:37, 17 December 2016 (UTC)
- I wouldn't assume that such a large number of devices would even work. While USB was originally designed to support up to 127 devices and Extensible Host Controller Interface#Scalability was designed to be able to support even more, it doesn't mean all implementations are going to actually work with that many. Notably XHCI seems to be explicitly designed so that manufacturers can choose how many to support and it sounds like 32 additional devices could be a problem [2] [3] [4] [5] bearing in mind that the hubs and controllers will also likely count and there are also other things like endpoints that come into play. Although if you're using one 16 port hub per USB port you may have more luck then if you're trying to use two 16 port hubs on one USB port. Nil Einne (talk) 00:15, 18 December 2016 (UTC)
- Thank you for those interesting links. My reading is that if the computer routes all 3.0 ports through a single xHCI controller with a limit of 96 endpoints, and some of the devices connected to the hubs use considerably more than two endpoints per device, then there will be problems connecting 32 devices, and that this limitation is fairly common. Dbfirs 09:40, 18 December 2016 (UTC)
- I wouldn't assume that such a large number of devices would even work. While USB was originally designed to support up to 127 devices and Extensible Host Controller Interface#Scalability was designed to be able to support even more, it doesn't mean all implementations are going to actually work with that many. Notably XHCI seems to be explicitly designed so that manufacturers can choose how many to support and it sounds like 32 additional devices could be a problem [2] [3] [4] [5] bearing in mind that the hubs and controllers will also likely count and there are also other things like endpoints that come into play. Although if you're using one 16 port hub per USB port you may have more luck then if you're trying to use two 16 port hubs on one USB port. Nil Einne (talk) 00:15, 18 December 2016 (UTC)
- Also note that on most PCs, the USB ports are connected to an internal root hub. This will limit the number of devices that you can connect to each port to less than 127. If you use MS-Windows as your operating system, then you can find how the ports are connected. To do so, start the "Device Manager", change the View to "View By Connection". You then need to find the USB controller(s). They are probably (from memory, not using Windows at present) under PC / PCI bus. If you expand the USB controllers, you can see which devices are connected to them. If you move a USB device between ports, you will see which controller is responsible for that port. 81.187.116.230 (talk) 15:12, 18 December 2016 (UTC)
I don't know guys, this is the following research:
I went to the "Device Manager" - "View" list option is automatically set to "Device by type" feature. I see a "Universal Serial Bus Controller" and a "USB Virtualization" drop-down-list, both already open.
1)
In the "Universal Serial Bus Controller" drop-down-list, I found:
3 "Generic USB Hub" ports. - nothing connected by myself so don't know why it is showing.
1 "Mobile Connect - Bus Enemurate Device" port (guessing this is for the Internet dongle as it is connected by myself, on one of the right-hand-side port).
2 "Intel(R) Series/C216 Chipset Family USB Enhanced Host Controller - _ _ _ _ _ _" ports - nothing connected by myself so don't know why it is showing.
1 "Intel(R) USB 3.0 eXtensible Host Controller" port. - nothing connected by myself so don't know why it is showing.
1 "Intel(R) USB 3.0 Root Hub" port. - nothing connected by myself so don't know why it is showing.
1 "Realtek USB 2.0 Card Reader." - nothing connected by myself so don't know why it is showing.
3 "USB Composite Device" port. - nothing connected by myself so don't know why it is showing.
1 "USB Mass Storage Device" port. - nothing connected by myself so don't know why it is showing.
2 "USB Root Hub" port. - nothing connected by myself so don't know why it is showing.
2)
In the "USB Virtualisation" drop-down-list, I found only "USB Virtualization Connector Driver. - nothing connected by myself so don't know why it is showing.
3)
Now, I'm not really a computer type person, all I know is, I have one USB v2.0 port at the left-hand-side of my Laptop connect with an external 4 port hub (keyboard, mouse and a numeric keypad connected as usual. Sometimes I connect my game-pad, regardless power loss occurs and I understand now why so).
I also have (probably something like a card/USB internal hub type or so, not sure though) two USB v3.0 port on the right-hand-side next to each other (each are connected with one RHDD and one SSD without any hubs (currently none are not connected because I'm using the internet). A slot for SD card i.e. in use facing towards me...
I wish to buy two 16 port hubs (one for each port resulting in giving me 32 ports altogether) cause I'm guessing USB v3.0 will last a long time... What do you guys suggest?
103.230.104.23 (talk) 19:08, 18 December 2016 (UTC)
Does the laptop have a built-in card reader? That could be the "Realtek USB 2.0 Card Reader" or the "USB Mass Storage Device". The keyboard and touchpad will either be connected via internal USB or PS/2. However, I wasn't interested in the list of internal USB devices, only the number of root controllers. 81.187.116.230 (talk) 19:35, 18 December 2016 (UTC)
- Considering many devices are already moving to USB type C (whether USB 3.1 gen 1, USB 3.1 gen 2 or even just USB 2.0) with some devices only having type C or only having type C for their 3.0 or later ports, your belief that USB3.0 on type A is going to last for a long time is questionable. Nil Einne (talk) 01:30, 19 December 2016 (UTC)