F.1. Criteria for the Transformation Format

• It is compatible with historical file systems (which disallow the null byte and the ASCII slash character as a part of the file name).
• It is compatible with existing programs. The existing model for multi-byte processing is that ASCII values do not occur in a single byte of a multi-byte encoding. An FSS-UTF representation of a non-ASCII character contains no ASCII code values. If the Unicode value is in the range [0x00, 0x7F] the transformation is in this range; otherwise, the transformed byte sequence does not contain any bytes in the range [0x00, 0x7F].
• It is easy to convert from and to Unicode.
• The first byte indicates the number of bytes to follow in a multi-byte sequence.
• The FSS-UTF is not be extravagant in terms of number of bytes used for encoding.
• It is possible to find the start of a character efficiently starting from an arbitrary location in a byte stream.