They have an issue where they explain that they have disagreements with how barrier is run and the current owner does not want to pass control to them. They are the most active recent contributors.
personally I am waiting for them to cut a stable release and then try it out.
Barrier and input-leap are nice and all, but they're written for only modern OSes using modern library versions and language features.
If you want to share a mouse with an OS older than a decade or so you'll still have to use the original Synergy 1.x. It works on both old machines/OSes (all the way back to the 90s) and on the very newest released OSes. Given that, I don't really see a need for barrier or input leap. They're kind of niche, but it's nice someone's keeping the codebase going.
Basically the only reason to use newer forks of synergy is if you have an abnormally high DPI screen in your span.
But Synergy is now commercial, with a stupid surcharge for TLS, so would it make more sense to say "the only reason to use synergy is if you're using an old OS and don't have hi-DPI screens"?
Gotcha, thanks. I used to use Synergy 1.x, and it was great. Recently returned to the fray and didn't have time to build-from-source (or didn't find an easy 1.x installer for new OS X) so grumble-grumbled and paid for Synergy 2. and expensed it.
I had a plan to run older period VMs or even period hardware to play older PC games, and use something like parsec to view them. Unfortunately, despite there being a number of desktop streaming solutions available I couldn't find any that supported even WindowsXP, much less 9x. Windows 7 was about the best I could do.
Interesting. I'm a long time Synergy user and recently tried Barrier and it simply didn't work. I'm going from a Linux server (personal) to a MacOS client (work equipment). Synergy has been mostly fine but I have had small problems that I was hoping Barrier would clear it up.
Thanks for linking this project, I wouldn't have seen it otherwise. Will be giving this a try this afternoon.
I don't know if this is still the case, but for a while it was both commercial and open source. You could change the license check to just "return true" and compile it yourself to get things like the SSL plugin. IIRC there was also a comment that detailed the algorithm for generating keys, so you could come up with one in your own name.
Barrier looks great, but does anyone know why KVM switches with DisplayPort or HDMI are so outrageously expensive? It should just be a switch, no complex electronics, so I truly can't figure out why any KVM should cost more than say $30-50 US.
I suspect DRM or patents for rent seekers are involved somehow. Or maybe they're playing on the naivety of the business community towards this stuff. I'd sure like to know, and also if there are any low-cost or open source KVMs available.
> It should just be a switch, no complex electronics
For any high-bandwidth thing like HDMI, you need to do clock recovery and copy over the bitstream at the very least. You can't just use relays or whatever. Doing this at 10gbps+ is going to cost a bit.
Even outside of impedence issues, you can't just use relays because then every switch is basically an unplug/replug, meaning that:
a) the display will flip out and spend multiple seconds re-syncing itself, and
b) the sources may take actions such as resizing the desktop, switching to the internal display, pausing the game, whatever.
Part of the point of a hardware KVM is that it negotiates its own connection to all of the devices involved, and only changes which signals are passed through at any given moment, resulting in instantaneous switchovers.
Now, a multi-input monitor can also do this, but then you have to deal with whatever compat issues are involved in commanding it to switch over DDC (see for example https://github.com/haimgel/display-switch), and it typically also won't be as fast as a hardware solution since input switching speed isn't a metric most people care about when monitor shopping.
Yup. A quick search suggests HDMI runs at clock speeds of 25MHz to 340MHz. Not running that over a relay! Also HDMI is many pins, so you would need a low impedance high pole count relay even if it was possible, and such a relay plus the device wrapped around it plus some profit margin means you're not making it any cheaper.
Shielding might be a problem. You need your switching circuitry (which is most likely going to be solid state rather than individual relays for each line) to be equivalent to a good cable in terms of interference, crosstalk, etc.
As soon as there's enough volume for someone to design a specialized IC (and reference PCB), and it gets produced by VIA or TI or whatever, sure, then it's neither a problem nor expensive.
There are really cheap commodity ICs that can switch HDMI, and they're generally purely analog devices that don't bother trying to reclock the signal. The real reason is that KVMs are specialised devices with a niche market. (Though there does seem to have been a bit of a push to integrate limited KVM functionality into some monitors lately.)
How many plugs and unplugs is HDMI rated for? At the prices we're talking it would be cheaper for me to build a robot that physically swaps cables at the back of my computer.
Of course then Windows gets confused by the lack of monitor and rearranges all the windows, so it's not a perfect solution.
It's pretty hard to beat a monitor with multiple inputs combined with a cheap USB switch when it comes to price and reliability.
If you look up the prices of stand alone hdmi switches on amazon though I think the most likely explanation is these are now niche products so the price has gone up. Logically a decent vga USB KVM + an HDMI switch shouldn't require more cost than those two devices prices together.
So, I might be missing something, but there are a couple of no-name HDMI/USB KVMs on Amazon in your price range (i.e., https://www.amazon.com/dp/B08NVKHRRT )
Some of the reviews suggest it acts as a pretty brain dead switch, which may cause problems with the OS. I know for a while I had a Windows 10 PC's monitor on a remote switch for silly reasons. I had to make sure to lock the PC before the monitor would turn off, otherwise some combination of driver/os/whatever would treat the disappearance of the monitor as a resolution change, and all my windows would get squished into 640x480. I could see KVMs like this triggering the same sort of madness.
I'd love a USB-only KVM style product, unfortunately newegg has decided to infringe on amazon's patent for "user must wade through endless ocean of unrelated garbage if sorting by lowest price".
Logitech has a keyboard that perfectly connects to 3 devices (unifying and/or BT) but they don't have a mouse that follows the keyboard and their mouse oriented work-arounds for that are garbage.
My first KVM switch was in the price range you mentioned, but switching caused the screen to go black for a while due to some HDMI stuff. The more expensive one I have now keeps both connections open at the same time, and switching takes a second or so.
I dunno, I started thinking of it like switching from one game server to another, if you (somehow) do it in the middle of a game, stuff is bound to explode.
I use this on my laptop and desktop when I bring my laptop into my office. It's totally seamless. You tell Barrier where the laptop "is" (relative to your monitor array -- just like setting up a secondary monitor) and then when you scroll your mouse onto your laptop everything is totally seamless. Your mouse and keyboard are then used solely for the laptop until you move the mouse back onto one of your desktop monitors.
The only bug I experienced was that the Barrier client would infinitely connect until you set up where that client "is" (as above) on the server. This is a pretty well-known issue at this point, but it would be nice if Barrier would say a bit more about errors (instead of being stuck on "Barrier is starting..."). There's a Show Log button in the File menu though which is nice.
Just an FYI for mac users: Universal Control is a native macOS alternative to barrier that's about to debut with macOS 12.3 (currently in beta). As an ex-synergy user, let me just say how awesome the implementation is. What's crazy is you can share your mouse and keyboard not only between two or more macs but also between your mac and an iPad (if you have one, obviously). And the latency is crazy unnoticably low (even over wifi).
I ask because the best use I had for Synergy was around 20 years ago: one Linux desktop (my daily driver) and other ones for non Linux applications (or ones I didn't want to pollute my system with).
Over the years I've used it for Outlook (connecting to Exchange), Lotus Notes, Xcode, Adobe tools, etc.
I've noticed that this doesn't _always_ work. Sometimes I just mash my mouse into the side of my screen and never get on to my iPad. So I've just switched to Logitech bluetooth mouse and keyboard. It's easier than a KVM and more reliable than software.
I can't install Barrier on my work laptop for policy reasons, but I don't want to buy a KVM, so a project I've been interested in building when I have time is porting enough of the Barrier/Synergy protocol to the Particle Photon [1] or BeagleBone Black [2] I've had lying around for a while, and then configuring it to emulate a keyboard and mouse via its USB gadget driver, allowing it to control my work laptop over USB.
On the Photon at least, emulating a keyboard and mouse is incredibly easy and is baked into the firmware, but implementing the Barrier protocol so that it can appear as a client on the network and pass on the keyboard/mouse input seems like it's going to take some effort.
The annoying/challenging part is that you need to drive the 2nd machine using relative motions, but place the cursor accurately and keep track of it. If the 2nd OS skips frames or has acceleration, you are pretty quickly implementing a Kalman filter.
It's been a while since I was deep in the guts of implementing USB HID devices, but I think you can specify in the descriptor if you're sending relative or absolute values.
There's a rewarding UX that can be made by switching the touchscreen to relative instead of absolute, you get more fine grained control.
Just about every virtual machine runner works around this by emulating a USB tablet (touchpad) and not a USB mouse. Should be simple to do same via USB gadget driver.
I recall some touchscreens use USB internally for the touch interface. A touchscreen has absolute coordinates, which does the trick, compared with the usual mouse/trackpad interfaces.
I remember remote controlling an OS that needed me to install absolute touchscreen drivers to work best (probably a VM, but maybe Synergy drivers??)
I'm not entirely sure I see what your describing with certainty, but are you talking about essentially a "barrier client appliance?" A dongle you plug into all the machines you want to control using barrier, which connects wirelessly to the barrier server daemon running on your main computer?
If so, neat idea, and I've done stuff like that before. You can even have the client appliances be configuration free -- they announce themselves to the network and the server pushes out after pairing.
Interesting and fun to build, but I don't quite see the use of such a thing. It would still require running the barrier server on your laptop. I'd try to possibly go a different direction: A cheap device (RP2040 based?) that sits in between an external keyboard and your laptop. Other copies of the same hardware plug into the usb ports of other computers you'd wish to control.
More or less, but in my case I would only have to run the barrier server on my personal desktop, and won't have to install any software on the client I wish to control (in this case, my work laptop). I'd like to piggyback off of the existing Barrier code, since I already use Barrier to control my personal Surface Pro, which also sits on my desk.
I really wish my 49" Samsung Odyssey G9 supported DDC over DisplayPort, so I could also switch my monitor input via software, and essentially have a KVM without buying any additional hardware.
A major consideration for me is avoiding introducing any extra input latency between my input/output devices and my personal desktop, since I use it for gaming. I'm okay with trading off additional latency when controlling my work laptop in exchange for lower latency on my main desktop. That said, I may end up using my BeagleBone rather than my Photon, since it has an ethernet port, and running Linux may prove advantageous.
I would love more projects like this, especially ones that utilize the BBB.
Personally I've had the same need (shared keyboard and mouse) and same requirement (work policy preventing additional software) for many years now so have resorted to using a KM switch (no V) bought off eBay.
If you look up "KM switch", the first thing you'll notice is that most search engines will automatically assume you meant "KVM switch" instead. This is what I believe contributes to the highly niche market and niche prices for KM switches. Anything under $100 is rare, hence used ones on eBay being the better option.
It should be possible to have a series of Atmel 32u4 microcontrollers acting as a keyboard/mouse devices controlled by a single host device over I2C. The problem is that people with the skills and people with the motivation haven't overlapped in a significant way.
> The problem is that people with the skills and people with the motivation haven't overlapped in a significant way.
Yeah... I, uh, have the skills (and I'm guessing you do too), but I don't see the point of the product. But you're right, a KM switch could be made very inexpensively. Could also be made modular, and wireless (for people who are into that thing).
You don't even need heterogeneous nodes, I think. All the nodes could be the same -- an RP2040 (now my favorite microcontroller for personal projects) can handle being a USB device, and host. The nodes could connect to each other through a daisy chained i2c, with another layer above for autoconfig.
What would be a price people would pay for such a thing? Say, 1 control node and 3 client nodes (allowing you to control 4 computers with 1 keyboard and mouse)? You say under $100 is rare?
There are/were standalone off the shelf USB devices that sort of did this, minute the network part which I had some interest in. I own an old one, but since my main machine is linux it's lack of linux drivers made it of dubious usefulness to me. I could control a linux machine with it, but the software that captures keystrokes/mouse and then sends them off through a simulated keyboard/mouse only had Windows/Mac versions.
https://pikvm.org might be relevant; the BBB and Pi are pretty comparable for most purposes, so wouldn't be surprised if that code/configured would work with only minimal tweaks on your BBB.
They provide a version of some other keyboard and mouse sharing software that was approved. Then you can run that on the one work laptop with that problem while still using barrier, input director, synergy, etc on your other work computer
Anyone else ever wanted multiple cursors and multiple mice on one computer? Sometimes I'd rather move my hand to a different mouse than drag the cursor across all that screen real estate. Also the different pointers would stay put when not in use.
I'm not sure about multiple cursors but for the large screen real estate problem some mice have a "precision" button that changes the DPI which can be leveraged. The intent is to make the DPI much lower while pressed (or toggled depending) but many allow you to set what DPI value you want it to use directly. This allows you to specify that the mouse will move say 4x as fast while you hold the precision button which is a lot less hand movement and coordination than switching over to another mouse.
Basically manual static acceleration for those that hate automatic smooth acceleration but want to occasional move fast easily.
Alternatively if you're lucky enough to have reasonably steady hands you'd be surprised what you can get used to as a default static speed. My multi-monitor setup is over 70 inches horizontally but I can get across it in a flick or still move pixel by pixel if I want.
I've done that for paired programming, it was a decade ago, but IIRC Xorg made it pretty easy to set up. That said...do not recommend :). It's too jarring.
I used to use Synergy all the time before the computer got so powerful that I didn't need multiple computers to drive all the monitors and run things in VMs
Thanks for sharing, so awesome that someone did the fork of synergy to stay oss and free.
I was a big user of synergy 1 and was quite disappointed by the takeover that led to the current partially proprietary Synergy.
It was a slide, first "let's have a binary builds for paying users to fund the project" then "let's have important features only for paid users with a license code needed", then the guys goal was to create and develop a company, hiring dev and assistants... The original spirit was lost.
This annoyed me a lot based on the fact that it was not the original developer of Synergy.
So, for long time I was thinking of doing a fork. And so, I'm very grateful that some people did it and had the courage to continue it.
This still requires a dedicated monitor connection to each box with a hardware or source switch, right? Or a screen per device? That is, the KVM (in the VGA days) used to switch the mouse, keyboard, and video source so a single monitor, keyboard, and mouse switches across devices. But barrier doesn't try to solve that part, I think.
Modern HDMI KVM hardware switches seem rather expensive; anyone found a good way to "switch" the monitors as well as keyboard and mouse?
Some more modern monitors can also be switched by software. I personally use a laptop with an external monitor that is also connected to my desktop. Whenever I need to switch from laptop to desktop (using Barrier or Mouse without Borders on Windows) I then invoke the magic of ControlMyMonitor by the wonderful NirSoft [1] using an Autohotkey-shortcut. This way I can share my monitor with the desktop and laptop. Sharing the keyboard and mouse works with Barrier.
I provided some short instructions in an SO-answer [2].
You can switch video inputs using dcc (eg https://www.ddcutil.com/) so you could bind a hotkey to do that or if Synergy/Barrier/Input-leap can be scripted it could do that part too.
There is also a utility that watches for usb device change events on a cheap USB keyboard/mouse (no video) switcher that does the video automatically, but I had it lock up the usb stack on my Linux machine and never really got it to work reliably enough.
I use one of the cheap usb KM switches and changing the input on the monitor manually. Still kind of sucks, but better than nothing.
bumped into reading about ddc a couple times this month now. does this have support across wide number of monitors? i like high refresh rate monitors and want to switch between a macbook and windows pc quickly depending on home/work. seems like a lot of kvms are going to either choke, not have usbc inputs
Not an expert in this by any means, but I think all modern monitors have support for this (eg brightness controls, etc from an applet). Monitors are named, so it supports multiple monitors too.
Modern hdmi (I'd recommend dp versions instead of hdmi) kvm switches aren't very expensive. I'm using a 4 machine hdmi/keyboard/mouse/usb switch that was <$300. They make dual monitor ones too. Tho I just use a cheap hdmi switch for my secondary monitor because it doesn't emulate a connection to the PC while a different input is selected.
This allows me to extend my active desktop to two monitors, or show a different machine on the secondary monitor. I also use barrier for this two host configuration.
No need for additional hardware. Take two Barrier-connected computers, the mouse can travel from one screen to the other. When using the keyboard, it inputs on the monitor with the mouse focus. Since it's UI based you need a screen per device yes.
Have been using hardware KVM switches (HDMI/USB) from Belkin and some unknown brands from AliExpress since years. I don't remember the price exactly, but it was way under $100. I even contacted the Chinese manufacturer to change the PCB for me (I wanted the ports repositioned) and they did a very good and quick job for under $300. I'm talking dual computers in this case, not more.
Depends on your price range I guess. You can find iogear/belkin HDMI 4 port switches for a bit under $100. Generic ones will be even less (maybe even around $50). I personally use DVI KVM from iogear (GCS1104) which cost me about $130, one of my machines is a gaming rig with Nvidia card and it works flawlessly.
I use a multipairing mouse and keyboard (Logitech MX Keys and MX Anywhere) and have my personal laptop connect via Thunderbolt → DVI and work via HDMI. It means I have to press three buttons to switch but it's still pretty convenient, without the expense of a dedicated KVM solution.
I tried using Barrier in a fairly complex setup (Linux, Windows, Mac with all of them being sometimes unavailable). Found some annoying UX issues (Windows privileged/login screen kicks the mouse back into the original position on a different monitor) and more importantly the Linux machine would wedge itself with 100% CPU used by Barrier.
Interesting. I used it on Mac/win/Linux trio and it worked great except copy paste and when the machines went to sleep, it would have to manually be restarted.
I will soon have two macbooks on my desktop in front of me. I hope to use the older macbook to run background tasks, like uploading videos to youtube and as a third monitor.
I have keychron k1 keyboard and an mx master mouse. Keychron is currently connected to the USB hub due to led lights, latency. But the keyboard has a battery and can work off of bluetooth. Mouse is connected through the tiny dongle that comes with logitech mouses. Both Keyboard and Mouse claim to work off Bluetooth.
Can I use this program to share the keyboard and mouse between the two macbooks? Or is using Bluetooth or a kvm switch a better option?
While 12.3 (and iPadOS 15.4) support older versions, Universal Control has more stringent requirements and only supports:
MacBook Pro (2016 and later)
MacBook (2016 and later)
MacBook Air (2018 and later)
iMac (2017 and later)
iMac (5K Retina 27-inch, Late 2015)
iMac Pro, Mac mini (2018 and later)
Mac Pro (2019)
All iPad Pros
iPad Air (3rd generation and later)
iPad (6th generation and later)
iPad mini (5th generation and later)
I use this daily between PC and Mac (as well as PC/PC) and it is great. Much more stable than Synergy for me, with the only caveat that it gets confused if you change monitor setups on the fly.
I use barrier daily between my two laptops it take everywhere. it's great, except I have two issues. you can it copy /paste images between the two. and you cannot select which monitor the mouse moves off of.
I find myself wanting to copy screenshots between the two constantly, and if you have two monitors stacked vertically, I can pick the bottom monitor to be the edge monitor to go to my other computer.
I wish barrier devs were more active devs but it still works great
I wish there support for wired usb, e.g. I have laptop and surface go connected via usb-c. Not only should be faster but more reliable in case one end point connect to wifi ac and another to wifi n on the same router.
I love the look of this, but haven't been able to find any information about latency... It seems to be a local network solution? Light on details about how it works, short of reading source.
Synergy (off which this was forked) experience: On a hardwired pair of computers, no perceptible latency at all. On wifi connected computers, I'd see the occasional latency spikes where things stop moving, but effectively imperceptible the rest of the time.
You don't strictly need a local network, you could probably get it to work across a VPN. As long as you can get a TLS connection directly between the two devices.
In my experience the protocol is quite light on the network, because this directly influences where the cursor is on your screen you probably want to keep latency down as much as possible.
I've been using synergy, literally, since the year 2000. I used to play a lot of first person shooters and over that time I never had a latency issue with using a mouse/keyboard on my old computer to play games on my new computers (over ethernet). No perceptible difference.
I've had issues running it over wireless so instead I connect the computers with an ethernet cable directly and configure static IP's. Haven't had any issues. Luckily my PC has two NICs and the laptop uses wifi anyway so the ethernet port is unused.
Got this working on the 2.3.4 release branch. The 2.4.0 release has a critical error that hasn't been fixed in months (years?) so definitely look into the issues page on that one.
Personal opinion: Don't put anything that matters, or connections to anything that matters, on computers with rootkit anti-cheat software installed. Even if the company itself is perfectly respectful, there's too many instances of supply chain attacks and attackers loitering on internal networks to trust such a vulnerability. At all.
I've been out of the PC gaming scene for a fair while. Which anti-cheat software would you describe as the "rootkit anti-cheat" software? (and is that all the stuff that doesn't work on linux?)
There was a post[0] from a couple months ago for a piece of software called 'display-switch'[1]. It turns a simple/cheap USB switch into a n-computer KVM (however many systems the USB switch supports) by detecting the presence of the USB switch device on either system and switching the video input of the monitors using DDC/CI.
I've been using it for a couple of months and it's been a game changer. No more fiddling with monitor menus to switch inputs or wondering if the monitor is currently set to one computer or the other. You have to make sure your monitors support DDC/CI, though.
Switching multiple monitors simultaneously seems to take you into a whole new bracket I tend to associate with the 15-monitor fintech/daytrader market, with pricepoints to suit :(
synergy was free too, the paid client never amounted to anything and had lots of promise of cloud inclusion-y nonsense that didn't pan out. (I know I was gifted a subscription through a friend)
The name is still barrier though, has anyone more info about this fork?