James, You may be thinking of "Streams" in Windows files. Data can be hidden in secondary files on NTFS partitions. I believe it was developed to be compatible with Apple/ MAC systems. In any case the following is an example:
Run CMD On a NTFS partition D:\> echo Hello > FrontFile D:\> type FrontFile Hello D:\> echo Good Day >> FrontFile D:\> type FrontFile Hello Good Day D:\> echo Secret Info > FrontFile:BackFile D:\> type FrontFile Hello Good Day D:\> more < FrontFile:BackFile Secret Info Now add data to the FrontFile only D:\> echo Good Evening >> FrontFile D:\> type FrontFile Hello Good Day Good evening Now add data to the BackFile only D:\> echo More Secret Data >>FrontFile:BackFile D:\> more < FrontFile:BackFile Secret Info More Secret Data You will notice if you enter a DIR command that only the FrontFile will be displayed. Furthermore, the size of the file will reflect only the content of the FrontFile. Have a great day. Wally _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.netsys.com/full-disclosure-charter.html