Is USB 3.0-to-USB 3.0 data transfer between two Linux OSes possible?
This Is USB-to-USB data transfer between two Linux OSes possible? question and the answer is USB 2.0 which is simply outdated. As USB 3.0 is much faster than simple Gigabit Ethernet and I want to connect a laptop and a desktop both with SSDs, this would be a great solution. If it’s possible.
4 Answers 4
Yes, USB 3.0 makes full duplex data transfer possible, with 3.0 cabling. The specs are in section 5.5.2 of the USB specs. The link to those specs is given earlier in another answer. http://www.gaw.ru/pdf/interface/usb/USB%203%200_english.pdf
Cables are becoming easier to find- they can be bought on Amazon, for example, for under $8.00. be sure to buy DATA TRANSFER, male A to male A cables. Newer versions of Linux support the transfer.
I hope that helps someone- I searched for the answer for quite a while myself.
Care to add something about how this works under Linux? Will your USB ports show up as network interfaces?
this is the same exact answer from the other thread and it was equally useless there. you don’t explain how to do anything.
I found a cable as described in 5.5.2 (no VCC or D+/D- connected, USB 3.0 pins are connected as crossover), but they claim it’s for debugging only & that Mac, Linux, and Windows don’t support host-to-host file transfers. datapro.net/products/… I have found bridge cables, such as this: startech.com/Networking-IO/USB-PS2/… Bridge cables like this do NOT conform to section 5.5.2 of the USB spec and are active devices which need a driver. I’m unable to verify linux support.
Section 5.5.2 «USB 3.0 Standard-A to USB 3.0 Standard-A Cable Assembly» of the Specifications only defines cable and says «cable assembly is defined for operating system debugging and other host-to-host connection applications». Are you sure that usb3 a-to-a cable allows not only debugging (kernel.org/doc/html/v4.16/driver-api/usb/usb3-debug-port.html — needs xHCI debug capability DbC, which is optional for xHCI usb3 host controllers), but also file transfer? For file transfer there are active cables (with controller in middle), some listed at: ghisler.com/cables
While this doesn’t seem to be availabe, there are dual Gigabit Ethernet adapters (make sure to get a real dual NIC and not a NIC + switch) and that’s 2GBit. Disappointing. Then it’s down to bonding the two together. In my case, the desktop have spare PCI Express x1 ports so I will get a dual NIC card instead of converting USB 3.0 there. For the laptop, USB 3.0 expresscard (they make ones with practically disappearing ports) and an adapter seems to be the easiest.
And since we are bonding, the laptop and the desktop both have gigabit Ethernet already so I can reach 3gbit/s theoretically which is quite good for syncing two machines which are limited by SATA speeds.
Bonding ethernet is quite tricky. It requires special cooperation from the dual NIC driver ( can’t bond a different nic ) and the switch, which must support 802.11ad LACP. There is a poor man’s bonding driver in the linux kernel, but it can only allow you to send traffic to two different hosts at the same time, not twice the throughput to the same host.
802.3ad/LACP also doesn’t share the bandwidth to the same host. It sends packets out of one or the other NIC based on a hash of the destination MAC (or IP in some cases). So you can get 2Gbps in or out, but only if you are connecting to at least two different remote machines. You can’t get 2Gbps between only two machines, sadly.
The xHCI spec describes a debug port to connect two hosts together, but a debug port is optional and almost none of the xHCI hosts currently on the market actually have them. Also, as Alan said, there isn’t any Linux software to support it.
Sarah Sharp
I can’t find anything newer to contradict this, so looks like it’s a not the way to go. I would bet that even if it did work, the fact that it uses a debug port is going to slow things down considerably. Plus some systems only designate a single USB connector as debug-enabled, so not only would this male-to-male cable only work on certain machines, but only on one USB port on those machines as well!
I did find information on a Prolific PL2701 IC that can bridge two USB3 hosts, in a similar way to the older USB2 bridge cables. It says it supports RNDIS (network emulation), mass storage, and some other protocols. So looks like USB3 doesn’t alleviate the need for a special bridge cable to connect two PCs.
Introduction
USB is an abbreviation for Universal Serial Bus. USB is an industry standard type of port for connecting peripherals to your computer. A USB device can be used as soon as it is connected, without having to reboot the computer. USB was developed in the mid-1990s.
Mounting devices
The mount command makes a directory accessible by attaching a root directory of one file system to another directory, which makes all the file systems usable as if they were subdirectories of the file system they are attached to. USB drives should be automatically mounted, with an icon appearing on the desktop.
See Mount/USB for more information on mounting USB drives.
Renaming USB Drives
Sometimes you may want to rename a USB drive, usually for the purpose of adding clarity to identifying which drive is which. You may also choose to change the name of your USB drive for aesthetic reasons, such as controlling what appears on your desktop.
See Renaming USB drives for information on how to do so.
Actions on Plugging in
- you want to copy images from a flash drive to your photo collection, delete them on the usb drive, and show them automatically
- you connect a USB harddisk to the computer and the computer should backup some data to it
- you connect an encrypted usb store and want the system to mount the encrypted harddisk
This used to be done with hotplug but in later linux distros is done using udev and module-init-tools.
What you need to do is setup a script that is triggered when the device is plugged in.
USB Modems
A USB modem basically works by converting between a digital data stream used by the computer, and an audio stream going over the phone line to another modem at the other end of the connection.
See Using a USB modem for more information.
Compatible Hardware
Ubuntu is compatible with several different USB hardware devices such as printers, mice, keyboards, scanners and printers.
External Links
- Universal_Serial_Bus — Wikipedia article on USB.
- http://www.qbik.ch/usb/devices/devices.php — Linux USB devices.
- http://wiki.flimzy.com/index.php/Debian_on_USB
- http://www.debuntu.org/how-to-install-ubuntu-linux-on-usb-bar-p2 — Install a persistent Ubuntu on a USB disk.
USB (последним исправлял пользователь 41 2012-11-12 12:44:52)
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USB to USB console
I have a server to which I would like to have a console connection. Normally this would be done using RS232 port, or using USB to RS232 converter. But to me it seems like it must be possible to connect the two USB ports directly, given that one of the ports can be made to act like a device. If the port is an OTG (On-the-go), this should be possible as far as I understand. So my question is, given the above, would it be possible to directly connect two computers, using a single USB cable, for console access?
1 Answer 1
The link-level protocol of the USB is a very different one as the RS232. It uses 2 data wires, it is packet-based, it is master-slave and it can connect many nodes on a single wire (RS232 is bidirectional). The abbreviation of «universal serial bus» is a little bit misleading: it is designed to be so universal as the RS232 was, but it is not a stream protocol.
To have a direct stream connection between two machines, some type of data stream should exist over the link-level USB protocol.
The result is that in essence you have an usb-to-serial converter, which acts as an intermediary layer between the USB and a bidirectional data stream. It shouldn’t be rs232, and also it shouldn’t do a physical conversion.
You can buy a simple usb link cable to interconnect two machines. As two usb slaves can’t be connected directly, they also need some intermediary usb master. This works mostly by giving an usb-ethernet interface to the machines connected with them, but giving an usb-serial interface would be possible too, and these devices may exist.
Next to the RS232, the Apple has developed a hardware-extended solution named lightning for that, although I would suggest more the RS232 direction on practical reasons.
However, there is a much smaller diversity in the machines bioses of most PC architectures. If you want a console redirection with them, you have only a physical RS232 connector on the mainboard for the task. Most BIOSes/EFIs won’t even use an usb-to-rs232 connector, only the physical rs232 port on the motherboard.