A KVM switch sounds like it has the potential to be a complicated piece of hardware. It's not. Without this most charitable of devices, you wouldn't be able to make use of more than one computer with a single keyboard and mouse. Your desk would be cluttered with input devices of all shapes and sizes, your ambitions of multi-boxing your own 40-man World of Warcraft raid would be dashed, and you wouldn't be able to slack off at your place of business nearly as discretely. After all, the entire point of a KVM switch is that it requires some kind of physical response--like whacking a button on the device--to switch a set of input devices between different desktops connected to the switch.

Why does this matter?  Well, I don't have a KVM switch, but I do use a piece of software that's just as good: Synergy. This little open-source app has been my virtual KVM switch of choice for awhile now, but its time is just as quickly fading into the limelight. A new sheriff is in town, and he goes by the name of Input Director. Both programs allow you to control multiple, independent desktops (or laptops) using  a single keyboard and mouse sans any "switching over" whatsoever--it's as if you just have a giant, spanned desktop across your systems.

Since Synergy has been at the top of everyone's must-have lists for some time (including Will's!), I thought it might be prudent to walk through the additional benefits and heartwarming fixes that Input Director brings to the party. Throw up the dukes!

Round One: Supported Operating Systems

Winner: Synergy

Admittedly, the antiquated Synergy pulls off a victory in the operating systems department. Both Input Director and Synergy work with versions of Windows as far back as Windows 2000. The latter, however, supports Windows 95, Windows 98, and Windows ME--but that's not exactly why it gets the head-nod in this department, given the very, very few of you likely running any operating system that old. Synergy also functions in Apple's OSX 10.2 or higher... provided you can stomach your sacrilege at the thought of using this non-Windows OS (just reaching out to the site commenters on that one).

Round Two: Ease of use

Winner: Tie

This category is a little tough to work with, as both programs are pretty simple to use. You can set each to autorun once Windows loads up, and each will attempt to make a connection (or establish hosting) for whatever client/server or slave/master setup you've previously configured. It's as easy as that. Once the program verifies that a connection has been made, illustrated by the changed icon in your taskbar, then you'll be able to zip and zoom your mouse across as many screens as you want. Ta-da.

Round Three: Configuration/Features

Winner: Input Director (by a mile)

Synergy

This category's a biggie. Synergy's options are only configurable via the first screen that loads when you launch the program. After you've elected to connect to a server PC or set up your system as the client, that's it--like a racehorse, Synergy is off and running, and you have to quit and reload the program just to configure the options once again.

As for what you can configure, there's the paltry list of connection options like "Screen Name" and "port" -- nothing fancy there. As a host, you use a confusing series of text-based comparisons to establish how the screens of your systems are set up: "0 to 100% of Computer A goes to 0 to 100% of Computer B," for example. You can synchronize screen savers across the connected PCs and set a certain time interval (in milliseconds) of how long the system should wait with your mouse at the edge before switching over to the other screen. You can also assign hotkeys for functions like quick screen-switching and cursor-locking.

It sounds like a lot, but these options make up what one could consider a "lite to standard" package for an application of this type.

Input Director

For starters, Input Director can be reconfigured on-the-fly: You don't have to break your link between PCs to adjust a setting, nor do you have to then reconnect all your systems to see if it works. Synergy has the annoying habit of sometimes giving up, in that quitting and reloading the server PC's application doesn't always mean that the client PCs will reconnect sans error. Input Director goes through momentary losses in connectivity and reconnections flawlessly.

Input Director users can switch a PC between a preconfigured "Master" and "Slave" setup on-the-fly as well. When you're running your system as a Master configuration, adding new computers to your giant, spanned desktop is as easy as typing in their hostname and port and dragging an icon representing the PC to the left or right of an icon of your Master system. That's it. There are no crazy numbers or screen percentages to configure--this simple solution eliminates confusion when setting up your systems.

Not only does Input Director support connected systems' multi-monitor setups, but you can also connect PCs under a 128-bit, 192-bit, or 256-bit AES encryption protocol. As a further measure of security, Slave systems can further specify allowed masters by IP subnet or hostname. A fun option in the settings window will match up the LEDs on your keyboard (Number Lock, Scroll Lock, etc.) to the status of the buttons on the Slave device. You can also set up hotkeys that will block switching over to a new screen--useful if you're working right to the edge of your Master system.

Finally, there's the clipboard. Clipboard sharing is, in theory, enabled in Synergy. You're supposed to be able to copy and paste text from one computer to another, but in practice, I frequently found that this was a one-way path. Text would copy from a server to a client PC without error, but could never quite make it the other way around. In contrast, Input Director's clipboard-sharing feature works near-flawlessly. You still can't do more advanced treatments like copy screenshots from one PC to the other (if only), but I'm rarely lacking the ability to copy a piece of code or funny URL from different linked PCs.

Round Four: Oops

Winner: Input Director

I've been switching between Synergy and Input Director on and off in an effort to determine which one is a more stable choice of applications for screen- and input device-sharing. Synergy works pretty well, but there have definitely been times when either the host or slave device has simply stopped responding. Synergy will try to reconnect, but the resulting link doesn't always work flawlessly.

Input lag is Synergy's dreaded nemesis. Little is more frustrating than having your mouse cursor pause for seconds at a time when you switch between screens, and it happens frequently enough to affect Synergy's overall performance. The only way to restore access when this happens is to wait out the time or, for the impatient, mash ctrl+alt+delete and click cancel. Input Director has yet to lose signal out of the blue or suffer from lag in any fashion when hopping between connected PCs. For that, it takes this round.

Final Score: Input Director (3)  Synergy (2)

But, really, for its stability and easy-to-use configurations, the score is more like Input Director (3,000), Synergy (2). Make the switch today. Download Input Director here!

David Murphy (@ Acererak) is a technology journalist and former Maximum PC editor. He writes weekly columns about the wide world of open-source as well as weekly roundups of awesome, freebie software. Befriend him on Twitter, especially if you have an awesome app or game you're dying to recommend!