Points to consider while designing a file format

• prefer self-describing files (no external metadata)
• checksum
• version number
• magic bytes (at beginning or end)
• creation date
• encoding for dates, text, binary data must follow some standard.
• endian (little or big)
• use TLV (tag-length-value) ?
• use PNG idea - have series of chunks, each with a type, length and data. Unrecognized chunks can be ignored.

References

• https://en.wikipedia.org/wiki/File_format
• https://www.w3.org/TR/PNG/
• http://www.magicdb.org/filedesign.html
• http://www.perlmonks.org/?node_id=491321
• http://stackoverflow.com/questions/323604/what-are-important-points-when-designing-a-binary-file-format