The [[file system]] is volume-orientedorientated: the top level of the file hierarchy is a volume (disc, network share) prefixed by the file system type. To determine [[file type]], the OS uses [[metadata]] instead of [[file extension]]s. Colons are used to separate the file system from the rest of the path; the root is represented by a dollar (<code>$</code>) sign and directories are separated by a full stop (<code>.</code>). Extensions from foreign file systems are shown using a slash (<code>example.txt</code> becomes <code>example/txt</code>).<ref name="drobe naulls 2004">{{cite web |url=http://www.drobe.co.uk/article.php?id=921 |title=RISC OS filename translation |work=[[Drobe]] |date=2 January 2004 |access-date=25 April 2012 |last=Naulls |first=Peter |archive-date=9 July 2011 |archive-url=https://web.archive.org/web/20110709035738/http://www.drobe.co.uk/article.php?id=921 |url-status=live }}</ref> For example, <code>ADFS::HardDisc4.$</code> is the root of the disc named ''HardDisc4'' using the [[Advanced Disc Filing System]] (ADFS) file system. {{nowrap|RISC OS}} filetypes can be preserved on other systems by appending the hexadecimal type as '<code>,xxx</code>' to filenames.<ref name="drobe naulls 2004" /><ref name="osnews round 2004">{{cite web|url=http://www.osnews.com/story/6170/Emulating_RISC_OS_under_Windows/page3/|title=Emulating RISC OS, Page 3/3|website=[[OSNews]]|access-date=25 April 2012|archive-date=13 March 2012|archive-url=https://web.archive.org/web/20120313042944/http://www.osnews.com/story/6170/Emulating_RISC_OS_under_Windows/page3/|url-status=live}}</ref> When using [[cross-platform]] software, filetypes can be invoked on other systems by naming appending '<code>/[extension]</code>' to the filename under {{nowrap|RISC OS}}.<ref name="archive fitton 1994">{{citation |last=Fitton |first=Gerald |date=August 1994 |title=Fireworkz for Windows |periodical=[[Archive (magazine)|Archive]] |publisher=Abbey Press |___location=Glastonbury |volume=7 |issue=11 |page=21 |url=http://downloads.abacusline.me.uk/pdf/Arc/2007/GC0701.pdf |oclc=222434223 |access-date=25 April 2012 |archive-date=3 December 2013 |archive-url=https://web.archive.org/web/20131203024536/http://downloads.abacusline.me.uk/pdf/Arc/2007/GC0701.pdf |url-status=live }}</ref>
A file system can present a file of a given type as a volume of its own, similar to a [[loop device]]. The OS refers to this function as an image filing system. This allows transparent handling of archives and similar files, which appear as directories with some special properties. Files inside the image file appear in the hierarchy underneath the parent archive. It is not necessary for the archive to contain the data it refers to: some symbolic link and network share file systems put a reference inside the image file and go elsewhere for the data.
