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Can I use my laptop as a second monitor for my desk computer?

My wife and I are going to travel for two months and will take both our laptops with us. Due to the nature of our work we need to work with a dual screen system, but don't want to cart an additional monitor with us. Is it possible to achieve the same effect by connecting the two laptops and make one of them into the slave of the other? Do I need a special cable?

marked as duplicate by Ƭᴇcʜιᴇ007, studiohack Jan 5 '12 at 17:47

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  • It doesn't note windows in the question, although I suspect that is the case. If it's not, you can use xdmx on linux. – RobotHumans Jan 5 '12 at 16:48

Synergy won't precisely give you what you've specifically asked for - but perhaps in your particular case it'll actually fit the bill nicely.

Synergy allows you to share a single keyboard & mouse from one machine with many. You set up zones where as your mouse hits the edge of one screen, it ends up controlling another machine. It's really quite awesome. It's cross platform (Windows, OSX, Linux) and is fairly easy to setup (and is free).

Synergy summary image

EDIT: Here's some crayon between the dots regarding how Synergy could ever 'fit the bill nicely'. Jad didn't explain his use case, so we don't know how he intends on using the second monitor. If the extra monitor is to add pixels for a single application, then my Synergy suggestion quite obviously won't help. However, suppose he's programming something and wants a screen just for reference documentation.. Then Synergy is extremely helpful (this is what I've used Synergy for during the past ~5 years). Hence, as I stated on the first line, while this doesn't explicitly resolve the question Jad has asked, it may well resolve the actual need he has that's inspired this question.

There's lots of videos on youtube regarding Synergy you can check out: http://www.youtube.com/results?search_query=synergy

So with Synergy (vs what you actually asked for) you'd be missing the ability to drag windows/applications between machines. Obviously, you can set up regular file sharing to move documents/content between machines. Synergy supports basic clipboard integration (you can 'copy' a line of text on one machine, then 'paste' it on another). Anyway, perhaps that'll meet your actual need that inspired the question. Maybe not - could end up helping someone else who reads the question wondering about their options along these lines - hence my posting this answer.

  • He's got two laptops, that means two discrete computers each with their own screen, keyboard, and mouse: how will Synergy fit his needs as he's described them above? He doesn't want to control the two laptops from one keyboard and mouse. He wants to be able to use one of the laptops as a second monitor for the other laptop. – music2myear Jan 5 '12 at 17:02
  • Well, he didn't specify what he wants the second monitor for. If it's to review documentation on one screen while coding on the other, then Synergy is perfect - that's what I use it for. If he's got an application that he wants spread across both screens, then obviously that won't work. It depends on the use case. – James T Snell Jan 5 '12 at 17:06
  • If it's documentation that he wants running on the second machine, then the extra software running on the computers will only save him from moving his hands from laptop to laptop when he needs to turn the page. The "needing" nature of this question seems to me to put it possibly beyond the sort of thing you're proposing. – music2myear Jan 5 '12 at 17:53
  • @music2myear - you're doing a lot of interpreting on Jad's behalf. People use the term 'need' far too liberally. Anyway, thanks for your opinion. Let's see what Jad has to say. – James T Snell Jan 5 '12 at 18:02
  • I know. I tend to read a lot into what people say and do. It's a strength and a weakness. But I've learned that it's better to trust this feeling more often than not in 12 years of professional user and system's support. The times I mess up I can always apologize and do a better job. The times I get it right it saves hassle and enables me to offer top-level support that goes beyond the user's ability to communicate their real need. – music2myear Jan 5 '12 at 18:35

Doing a google search for "use laptop as second monitor" turned up a few results. It'll require an app and you won't be simply connecting display output ports on the devices because those connectors are only for sending to (output) a display and cannot except the correct sort of information as input.

The good news is there are several apps out there that work. The bad news is I have no experience with any of them.

Here's a Windows 7 specific setup with step-by-step instructions: http://bitsbytesand42.blogspot.com/2009/02/using-spare-laptop-as-secondary-monitor.html

While MaxVista, proposed by Nik above has a free trial, the software proposed in the tutorial above, ZoneOS ZoneScreen, is freeware.

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