Recently I got a new machine at work, and managed to keep my old LCD. I have to say, having two monitors has really increased my productivity. (Check out Jeff Atwood’s take on multiple monitors.) I absolutely love it. I can have Visual Studio open on one monitor and the MSDN documentation (and email etc) open on the other.
At home, though, that’s a different story. I don’t exactly have the cash right now to get a 2nd monitor for my desktop. I also have a laptop that I sometimes place beside my desktop. For awhile, I tried to use both, awkwardly switching between mice and keyboards. If you’ve done this, you know the feeling of accidentally typing on the wrong keyboard or moving the wrong mouse, sometimes with disastrous consequences. I wondered if there was some way that I could use both computers with the same keyboard and mouse.
My first instinct was to look into KVMs. They weren’t exactly what I needed, since they switch {keyboard, video, mouse} between two machines. I still wanted to use the laptop screen, so that wouldn’t work. I just needed to move the mouse from the desktop to the laptop, and take keyboard control with it.
As it turns out, there is a solution for exactly this problem! It’s called Synergy, and is an open-source project, so the software is free.
Synergy lets you easily share a single mouse and keyboard between multiple computers with different operating systems, each with its own display, without special hardware. It’s intended for users with multiple computers on their desk since each system uses its own monitor(s).
Fantastic! It’s even cross-platform, so you could potentially use it with the Mac and Linux box on your desk, should they exist.
In my case, I installed Synergy on both my desktop and laptop (both Windows XP) and plugged them into the same LAN. (It will also work over wireless, but is a little laggy.) I wanted to share my desktop’s keyboard and mouse, so I configured Synergy on my desktop with the “Share this computer’s keyboard and mouse” radio button clicked:
Then I needed to configure the Screens and Links, also on the desktop. This essentially lets me give names to each machine (I just called them “desktop” and “laptop” for simplicity) and also specify the “links” between them. It’s really easy. I wanted to configure Synergy so that when my mouse goes to the right of my desktop monitor, it gets teleported over to the left side of my laptop monitor. I also wanted the left side of my laptop monitor to teleport over to the right side of my desktop monitor. The second rule may seem redundant in this case, but if you don’t define it, then if you mouse from the desktop to the laptop, you have no way of getting back to the desktop! You can go crazy with the rules if you have more than one machine, creating a twisted maze of links and relationships between screens. For usability, though, it’s a good idea to keep things “topologically simple” to not fry your brain 
Here’s my Synergy setup:
Once I get the desktop configured, I just click the Start button and it hides in the tray waiting for clients (e.g. my laptop) to connect.
Then on my laptop, I start Synergy and configure it to use my desktop’s keyboard and mouse:
Click Start and the icons on both machines will show a yellow lightning bolt to indicate connectivity. Moving the mouse around actually jumps between screens! Sweet! You’ll also be pleasantly surprised when you discover that copy/paste works between machines as well.
Now I can have a “Dual” Monitor setup. It’s not quite the same since the screens are connected to completely different machines, but it does help considerably.
Lately I’ve been developing some distributed system software with WCF, and this setup has been very beneficial since I can easily move the mouse between two computers to test both client and server.
Hope someone finds this useful!
