The standard U.S. household wiring design has two 120 volt hot wires and a neutral which is at ground potential. The two 120 volt wires are obtained by grounding the centertap of the transformer supplying the house so that when one hot wire is swinging positive with respect to ground, the other is swinging negative.
Thus the name of a file or directory can be up to 255 characters. When specifying the full path under Windows, you need to prefix the path with \?\ to mark this path as an extended-length one (~32k characters).o be precise: NTFS itself does impose a maximum filename-length of several thousand characters (around 30'000 something). However, Windows imposes a 260 maximum length for the Path+Filename. The drive+folder takes up at least 3 characters, so you end up with 257.
The document is archived and information here might be outdated. This attribute contains the UPN that is an Internet-style login name for a user based on the Internet standard RFC 822. The UPN is shorter than the distinguished name and easier to remember. By convention, this should map to the user email name. The value set for this attribute is equal to the length of the user's ID and the domain name. For more information about this attribute, see User Naming Attributes.