The abstract pathname denoting the root directory has the prefix “/” and an empty name sequence.
Windows
For Microsoft Windows platforms:
the prefix of a pathname that contains a drive specifier consists of the drive letter followed by “:” and possibly followed by “\\” if the pathname is absolute.
the prefix of a UNC pathname (network shares) is “\\\\”; the hostname and the share name are the first two names in the name sequence.
A relative pathname that does not specify a drive has no prefix.