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juju · 02-19-2003, 04:13 PM

Yeah, I'm not really sure <i>why</i> this happens, but I know that it does.

I got a KVM off ebay for like $5-10, and it promptly killed my MS Intellimouse. Whenever I would switch between computers, the cursor would jump all around the screen whenever I moved the mouse, opening and closing programs at random, and just causing general chaos. I think this was because Windows sets the mouse to one protocol, and Linux uses another. So when I would switch from Linux to Windows, and then back, the number of bytes being used for the X and Y position was different, and thus the number was different. But even after I stopped using the switch, the mouse still did this, so I can only guess that some sort of permanant damage was done. I had to throw the mouse away and buy another one!

I also found that my monitor was flickering in weird ways whenever I switched over to windows. I think you might be right about it having something to do with a refresh rate problem. Anyway, after I stopped using the switch, the display problems mostly went away, although I still occasionally get vertical lines rolling across my screen whenever I use Windows, and this just didn't happen until I started using the KVM.

I do know that difference between the cheap KVMs and the expensive ones is that the former is purely mechanical, while the latter is software based. The good KVMs send a fake signal to the non-active computer, fooling it into thinking that the device is still there. This way, the OS doesn't lock up or drop the device if it tries to poll it and discovers it isn't there. Also, with the mechanical KVMs, you have to leave a computer switched on while it's booting up, otherwise you won't get keyboard/mouse/monitor support.

Still, what I do know about KVMs doesn't really explain why it destroys my devices, so maybe it's just me. I don't see any instances of fouled-up monitors on Usenet, but I do see lots of broken Intellimouse incidents.

02-19-2003, 04:13 PM	#24
juju no one of consequence Join Date: Jun 2001 Location: Arkansas Posts: 2,839	Yeah, I'm not really sure <i>why</i> this happens, but I know that it does. I got a KVM off ebay for like $5-10, and it promptly killed my MS Intellimouse. Whenever I would switch between computers, the cursor would jump all around the screen whenever I moved the mouse, opening and closing programs at random, and just causing general chaos. I think this was because Windows sets the mouse to one protocol, and Linux uses another. So when I would switch from Linux to Windows, and then back, the number of bytes being used for the X and Y position was different, and thus the number was different. But even after I stopped using the switch, the mouse still did this, so I can only guess that some sort of permanant damage was done. I had to throw the mouse away and buy another one! I also found that my monitor was flickering in weird ways whenever I switched over to windows. I think you might be right about it having something to do with a refresh rate problem. Anyway, after I stopped using the switch, the display problems mostly went away, although I still occasionally get vertical lines rolling across my screen whenever I use Windows, and this just didn't happen until I started using the KVM. I do know that difference between the cheap KVMs and the expensive ones is that the former is purely mechanical, while the latter is software based. The good KVMs send a fake signal to the non-active computer, fooling it into thinking that the device is still there. This way, the OS doesn't lock up or drop the device if it tries to poll it and discovers it isn't there. Also, with the mechanical KVMs, you have to leave a computer switched on while it's booting up, otherwise you won't get keyboard/mouse/monitor support. Still, what I do know about KVMs doesn't really explain why it destroys my devices, so maybe it's just me. I don't see any instances of fouled-up monitors on Usenet, but I do see lots of broken Intellimouse incidents. Last edited by juju; 02-19-2003 at 04:17 PM.