A failed update that resulted in an unmounted disk0s2 During a strange glitch update yesterday I ended up with a circle with a diagonal dash in it .

I had backed up though .

I have restarted with command/r 
Now I have attempted to install the a new os version in the many ways available , but my disk is missing ( not visible ) 

When I go to reinstall osx mavericks , there is current osx disk available 

When in time machine restore , there is also no disk available 

Now I am in disk utility
I can see a disc0s2 . Which is listed as not mounted !

I'm not sure what to do 

Help please ?
You should download the app Mountain.  This app places an icon in your menu bar. When opened it lists all volumes on your machine and you can mount or umount them. The app can be downloaded for free but you may have to pay for extended use - $6 I believe. I am in no way affiliated with Mountain, just a happy, long time owner.