I set my startup disk to Macintosh HD. But after opening it, the name becomes "/"

Using the System Preference -> Startup Disk I set my startup disk to Macintosh HD. When I open it the name at the top of its window is "/". When I open the startup disk using Applescript it opens Macintosh HD, but the name of it becomes "/". Is this normal behavior? My actual applescript code is this.

  tell application "Finder" to open startup disk    
  tell application "Finder" to get the index of Finder window "Macintosh HD"

But the 2nd line produces the error message

error "Finder got an error: Can’t get Finder window "Macintosh HD"." number -1728 from Finder window "Macintosh HD"

if I replace 2nd line with:

tell application "Finder" to get the index of Finder window "/"

It gives me the expected answer of 1.

The image below shows the window Macintosh HD. Notice the name at the top of the window and the name at the bottom of the window. Can someone tell me if this is normal or do i have a problem?

Solution 1:

The Finder normally uses the folder name in its window titles, but a preference can be set to show the POSIX path. From the Terminal, the following command will set the preference, where true will show POSIX paths, and false will just use the name - in earlier systems the Finder may need to be restarted for it to take effect (the killall part):

defaults write com.apple.finder _FXShowPosixPathInTitle -bool false; killall Finder

Solution 2:

Macintosh HD is the partition name. The mount point is /, however. Other volumes are mounted in the /Volumes/ directory, such as /Volumes/MyDisk, if MyDisk is the name of the partition. This is similar to how Windows operates, where the boot disk is always C:\.

I'm not sure why Finder is showing it as /, though. On both my Mojave and Sierra machines, it shows "Macintosh HD". I don't have the bottom info bar, so that may be the reason.