a POSIX device ID
| std_types::object | the prototype object for all "normal" objects |
| std::stat | retrieves status information about the specified file |
| std::fstat | retrieves status information about the file described by the specified file descriptor |
| std::equal | compares two device IDs for equality |
| std::hash | returns an integer hash value for a device ID |
| std::to_integer | returns an integer value representing the device ID |