The <dfn>Ruler</dfn> scales the session along time, allows navigating, and can be marked for different uses. The main use of the Ruler is to move the playhead: clicking anywhere on the timeline will bring the playhead at this location in time.
<dt><dfn>Timecode</dfn></dt><dd>scaling the session whith the traditionnal Hours:Mins:Secs:Frames notation</dd>
<dt><dfn>Bars:Beats</dfn></dt><dd>slicing the time according to the time signature ot the Meter</dd>
<dt><dfn>Meter</dfb></dt><dd>shows the time signature. It can be changed along the timeline, by <kbdclass="mouse">Right click</kbd>><kbdclass="menu">New Meter</kbd>. The Bars:Beats ruler will reflect the change.</dd>
<dt><dfn>Tempo</dfn></dt><dd>shows the BPM. It can be changed along the timeline, by <kbdclass="mouse">Right click</kbd>><kbdclass="menu">New Tempo</kbd>. The Bars:Beats ruler will reflect the change.</dd>
<dt><dfn>Range Markers</dfn></dt><dd>allow to create and modify ranges directly on the Ruler.</dd>
<dt><dfn>Loop/Punch Ranges</dfn></dt><dd>are special kind of ranges designed to be played as a loop and to do punch recording, i.e. recording on a precise section of time, respectively.</dd>
<dt><dfn>CD Markers</dfn></dt><dd>are markers designed to be used while creating a recording that has to be split in time, as an audio CD</dd>
<dt><dfn>Location Markers</dfn></dt><dd>is meant to receive any kind of marker, user generated or from Ardour itself.</dd>
Most of the operations on the markers are described in <ahref="@@working-with-markers">Working with Markers</a>, while the Meter, Tempo, Bars:Beats and Timecode use are described in <ahref="@@tempo-and-meter">Tempo and Meter</a>.