I use synergy http://synergy2.sourceforge.net/ for sharing one mouse and keyboard across two monitors and OSes. I use Linux on the right and Mac on the left. Would never go back. Like someone said read documentation on one, code on another.

Cool setup, thanks for the info. I know you can do that with vnc somehow as well.

1) Why? As others have said, enhanced productivity. I usually keep API docs, examples, and a terminal with autotest on my secondary. Also, in my case, my machine is a laptop (I use that screen as my secondary) and knowing I have a 24" screen waiting for me is incentive to come into the office instead of telecommuting or siting in a coffee shop :).

2a) How? Been awhile since I've had to deal with installing new hardware, but as far as I remember, you can install new video cards and it'll register fine (or get a card that has two DVI ports). As for OS support, I think Windows does it (although I don't know if you have to have a certain edition), Mac supports it on most models out of the box (in the past you had to do a software hack on iMacs, don't know if that's still the case—other than that completely painless), and I know it's possible with Debian (probably most other Linuxes as well).

2b) What's it look like? Most current hardware will support spanning across multiple screens (OS support: see caveats above). In the past, some video adapters didn't have the horsepower to do anything other than mirroring (where the screens show the same thing), but all of the ones I've dealt with recently can (again, YMMV). Mirroring is still useful when hooking up to a projector, but beyond that, spanning is the way to go.

Definitely try it. I will never be able to go back to one monitor.

Here are some statistics: http://www.codinghorror.com/blog/archives/000012.html

Here are instructions: http://lifehacker.com/software/dual-monitor/how-to-set-up-du...

Thank you so much for the link to the video.

It's very easy to setup and really amazing... I just tested it out on my laptop with my computer's monitor(I plugged my computer's monitor in the laptop instead)... and it's really cool.

I use two 15 inch laptops (Vista and Kubuntu) and one 22 inch screen in the middle.

Depending on the type of work I do (Windows development or nix) I physically switch main screen between two laptops. For example, when I do Outlook add-in dev, my screens might look like this:

Vista laptop: Outlook where I test. Vista main screen: Studio. Kubuntu laptop: docs.

or

Vista laptop: docs. Vista main screen: Studio. Kubuntu laptop: VMWare with different OSes. This way I don't overload Vista machine which is already running studio.

For nix dev, I like this setup:

Vista laptop: chats, music, videos, whatever. Kubuntu main screen: Emacs fullscreen. Kubuntu laptop: docs.

As is probably obvious, my setup looks like this:

Vista - Main Screen - Kubuntu

I also use synergy to handle supporting laptop (Kubuntu or Vista) from main machine.

I have to say, it really helps. There is a lot of ease on my brain which helps me relieve some of the anxiety.

I can think of a couple of reasons

- Sheer geekery (though that doesnt work with your comment about cost, I admit).

- Multiple PC's (example: at my desk I have a dual screen setup for working on, a 3rd screen connected to a different PC for email, IM [chatterous via Gtalk ftw] & personal stuff and a smaller screen off to one side which is a build machine / test client. Using a KVM to share Kb/M but still being able to see all screens is a great advantage :))

It's a documented trend that more monitors enhances developer efficiency. There is a point of diminishing returns as well, so two or three is the sweet spot. Some can see improvement with four, but not many.

I apologize, I can't find the source of the study for efficiency.

That being said, some prefer a single screen. I love dual screen as I'm a big proponent of code on one screen and website on the other so I can easily see the results of my code.

I have a main setup comprised of 3 displays with one desktop and a laptop, it's quite nice to work like this, especially when I run macosx and then have windows in vmware fusion on another display.

The only thing I'm torn on is rotation. I've flipped a display 90 degrees around and I can't decide if I like it or not. It's decidedly odd but quite useful in some ways (i.e. for me, reading long things without using scroll so often).

Imagine you're trying to write a letter on a piece of paper but the desk you're writing on is only 3cm². Were it bigger, it would be so much easier.

Left monitor has mozilla with tabs and behind that a terminal with database command line.

Right monitor has outlook and my main terminal window plus itunes in the background (or whatever I'm listening to).

It is incredibly nice to compare 2 files across the monitors. Also it is nice to be able to have ie6 or ie7 in one windows with mozilla or safari in another to make sure everything lines up correctly.

Testing sites for browser compatibility and rendering issues, most likely; though having 1+ screens probably isn't necessary. I would think it would be much easier, and more cost-effective to go with a KVM switch than a bunch of different monitors. Perhaps could be useful for testing site renderings on different monitor resolutions.

Once you've had double-headed there's no going back. Try it!

2 monitors is cheaper than 1 really big monitor. more screen space makes multitasking easier, improving productivity.

maybe it's the 'secret weapon' for those startups

is there any data of #monitors used during early product development on various startups?

All of the studies out there are pretty rudimentary, so, I would doubt that there are detailed statistics like that.