I have extracted hard disks from otherwise dead Mac laptops.
I'm using them as external hard disks, but I cannot use all the space they contain because they have a few system folders (like
/System) which are of no use at all to me now.
It seems I cannot delete them using the terminal (even as
sudo) or with Disk Utility (If I ask this app
to erase the whole volume it refuses).
Did I miss something? What is the best way to do this?