Can someone explain what Disk Utility sees Mounted?

[blackxacto]

Macintosh HD
Yosemite
EFI
Macintosh HD
Boot OS X
EFI
Macintosh HD
Recovery HD

BackMeUp
BackMeUp
EFI
BackMeUp
Boot OS X

My main HD is called Yosemite.
My backup is called BackMeUp.

In Disk Utility for Yosemite 10.10.2,
what do the 4 to 7 items mean?

Is there a link to a web page that explains what Disk Utility is seeing?

I am asking because I am never sure what item to highlight before repairing. I assume I select “Yosemite", but why not “Macintosh HD”?

iMac14,2 / 3.5GHz Intel Quad Core i7
8G RAM / OSX10.10.2 / 3TB Fusion HD

 

[Taz Mangus]

Macintosh HD
Yosemite
EFI
Macintosh HD
Boot OS X
EFI
Macintosh HD
Recovery HD

BackMeUp
BackMeUp
EFI
BackMeUp
Boot OS X

My main HD is called Yosemite.
My backup is called BackMeUp.

In Disk Utility for Yosemite 10.10.2,
what do the 4 to 7 items mean?

Is there a link to a web page that explains what Disk Utility is seeing?

I am asking because I am never sure what item to highlight before repairing. I assume I select “Yosemite", but why not “Macintosh HD”?

iMac14,2 / 3.5GHz Intel Quad Core i7
8G RAM / OSX10.10.2 / 3TB Fusion HD

You select the hard drive where OS X is installed. In this case it would be Yosemite. If you select another partition the Repair Permissions button will be greyed out. Where are you seeing that, from the terminal app running "diskutil list"?

EDIT: I just realized after reading another thread about partitions in 10.10, it appears that your partition has been converted to core storage. I have not seen this before and this has not happened to me with 10.10.2. From what I have been reading you won't be able to repair permissions until you convert the partition back to a HFS+ partition: http://apple.stackexchange.com/questions/134498/unable-to-resize-partitions