Two external keyboards, one for right hand, one for left hand, modifiers do not work

I am in my bed. MacBook (Yosemite 10.10.2) is on my chest.

I have one external keyboard (with trackpoint) for my left hand and another external keyboard for my right hand.

This would be awesome if it would work.

But the problem is that when I hold shift on the left keyboard and press P on the right keyboard then Mac writes a p instead of a capital P.

If I hold shift on the right keyboard and then p on the same keyboard then Mac writes a capital P as it should.

The same problem happens with all modifier keys:

If I try to use one modifier key on one keyboard and the to-be-modified key on the other keyboard then the result is simply the to-be-modified key unmodified.

Any idea what is causing this behaviour ?

How can one fix this ?

iMac and MacBook Air shared monitor

I have used a thunderbolt connection and pressed Command F2 to allow my track pad and keyboard on my MBA to run both screens. However, I want to use the wireless track pad and keyboard that comes with the iMac instead of the laptop track/keyboard. In other words, I would like the iMac to be the primary computer and use the laptop as a secondary screen (with all control remaining with the iMac). Is this possible?

Safari keeps warning "malicious javascript detected on this domain"

Safari keeps warning malicious javascript detected on this domain, and there is only a OK button to click. It is stupid to click OK again and again. How to prevent this?

I think the so-called malicious javascript is just some code for ads, because I saw this warning at a few websites of large company.

Does disabling SIRI still replace it with old Voice Control?

I have 2 questions about disabling SIRI I hope somebody can help with:

1. 
   

   If you disable SIRI in general, will holding the home button (when phone is locked) activate the old Voice Control instead or not anymore? Anybody with IOS 7 or 8 can test this for me?

   
   


2. 
   

   If you go to Settings -> General -> Passcode Lock -> "Allow access while locked", you can disable SIRI when your phone is locked, however will this only work when you enable passcode and not when you disable it afterwards. Anybody can test that for me? Thanks alot!

   
   

Why Doesn't OSX root user automatically default to the same shell as other users

I know this is a stupid question, but I have googled this and searched Stack Exchange, and have not found an explanation for why the root user on OSX doesn't automatically default to the same shell as other users. Seems like this would avoid a lot of complications, but I guess there must be complications with the shells being the same for root as others, but I just don't know what they are.

Thank you.

How do i quickly silence all notifications except for ringer on an iPhone 6?

Sometimes I'm on call for work overnight and would like to know a quick way that I can silence all notifications except for the call ringer. The closest thing I see is allowing calls from everyone on do not disturb but that will allow messages to ring as well.

Can't erase unmountable external HD

My external HD isn't mounted and can't be repaired by Disk Utility. However, I'm also unable erase the disk:

$ diskutil list disk2
/dev/disk2
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *4.0 TB     disk2
   1:                        EFI EFI                     314.6 MB   disk2s1
   2:                  Apple_HFS Everest                 4.0 TB     disk2s2

$ diskutil repairVolume /dev/disk2s2
Started file system repair on disk2s2 Everest
Updating boot support partitions for the volume as required
Error: -69673: Unable to unmount volume for repair

$ diskutil eraseDisk JHFS+ Everest /dev/disk2
Started erase on disk2
Unmounting disk
Error: -69888: Couldn't unmount disk