to be used only to allow representing files with data extents that are larger than 4GiB-2048. Duplicate file records are not to be used to represent files with fragmented data. When duplicate file records are used, the multi-extent flag must also be used as indicated in ISO-9660-1999 specification. Duplicate file records should not be created unless the total data size of the file is greater than 4Gib-2048. When duplicate file records exist for a file, all but the last file record must have a data extent that is exactly 4Gib-2048 bytes in size. Location of directory data on media All file data must precede all folder extents and path tables on media. The intent is that an image modifying application can read the entire directory into memory, add new file data to the image, and rewrite an updated directory after the new file data. Writers will need to determine the last block of file data after reading the entire directory. Media header patch area When the media header is modified, either at the end of image creation or as part of later modifications to an existing image, only some specific fields are to be updated. These fields exist entirely within the media header patch area. Only the media header patch area should be re-written. This allows more options when dealing with image container file formats or transports with limited seeking or overwrite capability (compressed formats, pipes, sockets). Format extensions and compound file systems All files and folders written in the image must be accessible through the single directory structure referenced from the supplementary volume descriptor. Compound file systems, such as including UDF or HFS structures, are not allowed. Rockridge and other ISO-9660 extensions are not allowed. Extensions for archiving system specific attributes Future versions of CFS may include extensions to allow storing system specific attributes such as time fields, security descriptors, access control lists, resource forks, symbolic links etc.. Developers with a need for these extensions should contact Pismo Technic with requirements and/or suggestions. Media formats CFS images are either written to CD/DVD media, or are stored in a media container file. The media container file can be a raw dump of the CFS image, referred to here as DD, but more commonly known as ISO files. Also, the media container file can be a more structured container format that provides additional features such as compression and spanning. CFS images