There are various arbitrary restrictions in various filesystems and operating systems.  The intention is to store smaller amounts of useful information with the file.  Smaller means in the bytes&#x2F;kilobytes range.  For example you wouldn&#x27;t store multi-gigabyte alternate language versions of a video file in its extended attributes.  But you could store URLs of where to get them.<p>Or you could attach authorship, review, dates, keywords and similar metadata which would work for any file type, not just those whose format explicitly has that support.<p>If you want to get a handle on what filesystem design is like then I highly recommend Dominic Giampaolo&#x27;s book on the design and implementation of the Be filesystem (he wrote BeFS).  The book is freely available from his website as <a href="http:&#x2F;&#x2F;www.nobius.org&#x2F;~dbg&#x2F;practical-file-system-design.pdf" rel="nofollow">http:&#x2F;&#x2F;www.nobius.org&#x2F;~dbg&#x2F;practical-file-system-design.pdf</a> and includes information about the design of other filesystems too.  It isn&#x27;t exhaustive, but does give a very good grounding in filesystems and does cover extended attributes.