Why can't I use two or more keyboards/mice at the same time on one computer?

Question

This is just a question of curiosity. Why cannot I use two keyboards at the same time in Windows? For example, typing in Notepad using 2 keyboards in real parallel mode. Is there any multitasking or parallel processing OS that can do it?

Answer 1

Parallel, simultaneous use of multiple input devices on one computer is technically possible, but not widely supported because there is lack of demand. It would require extra software developer time to design, test, and maintain such a feature. Most software companies, including Microsoft, choose to devote developers' time to other features that are more in demand.

However, some companies decide it is worth putting in the extra effort. Mouse Party is an example of software that supports up to 9 mice pointers simultaneously on one computer:

Now with Reflexive’s Mouse Party™ , UP TO 9 PLAYERS AT ONCE can play a video game - simultaneously ON THE SAME COMPUTER!

Each Reflexive game featuring the Mouse Party logo (LOGO) supports this unique play mode where multiple people can gather around the same PC and play cooperatively or competitively with the other players.

Ready to liven up a get together, or have a little friendly competition to see which of your family members gets a night off from doing the dishes? Mouse Party is just the ticket!

Note: I was originally thinking of a different game that supported "party-mode" mice (perhaps the first one to do so?), but couldn't find it. It was released several years ago. I think each player controlled their own pirate ship. Anyone else remember this game?

Answer 2

No OS that I know of supports two independent cursors, or keyboard inputs to the same session.

Microsoft does however support two (or more) different users sessions on one PC. It's called Windows Multipoint and is aimed at medical and educational situations, but could work anywhere really. This allows a PC to have two keyboards, mice, and screens at the same time; and the sessions on the screens are independent.

HP makes a MS 6000 desktop that does this, and T100 modules to plugin additional stations. You can add quite a few additional stations if the workload is very light.

X can already do this sort of thing by setting up two different X servers with different configurations (for the screen, keyboard, and mouse).

Answer 3

There is a project called Multi-Pointer X (aka MPX) on X.org user system (like Linux). Here is a demo.

But I think that a MPX-like system would be available on Windows, help to the "Surface" project development and the new multi-touch supports.

Answer 4

There are other good answers looking for workarounds, but none so far seem to explain why the feature doesn't exist. Windows can't do this for a number of reasons. Among them:

1. Nobody programmed this feature because very few people would use it. Although you clearly have a desire to play with this feature, how many people could use this? Programmer time isn't free, so paying them to design this feature would necessarily prevent the development of some other feature. What feature in Windows would you like them to have not programmed in order to have this?

2. The user interface for this would be confusing. The mouse cursors and insertion points could have different colors to tell them apart, but when you click to start typing somewhere, which keyboard gets the input? Does each mouse create an insertion point for just one of the keyboards? You've now also created the concept of having two simultaneous active windows. If they overlap, which one is on top? If a program asks the OS where the mouse pointer is, which one does it get the answer for? I'm sure there are tons of other situations where a new UI would need to be designed to accomodate two independent input sources.

Answer 5

MS research is working on two or more mice here.

http://research.microsoft.com/en-us/um/india/projects/edulab/multipoint.html

Answer 6

I never had such problems. On my Windows Vista, I am currently using 2 keyboards (one internal to the laptop and one external), and it works properly. I can even press shift on one, and it works (though the same doesn't work properly on Linux). I can also use 2 mice (I tried the touchpad and an external mouse, and also 2 external mice).