A ShortString is 0 to 255 characters long.
While the length of a ShortString can change
dynamically, its memory is a statically
allocated 256 bytes
the first byte stores
the length of the string, and the remaining
255 bytes are available for characters.
If S is a ShortString variable, Ord(S[0]),
like Length(S), returns the length of S
assigning a value to S[0], like calling SetLength,
changes the length of S. ShortString uses 8-bit ANSI
characters and is maintained for backward compatibility only.