Most of the symbols and icons used as part of the iPod display format are relatively straightforward and easy to understand. The Pause and Play symbols -- two side-by-side vertical lines and a right-facing triangle, respectively -- are nearly universal, as is the padlock icon used to indicate that the iPod's controls have been locked. Not all icon meanings are so ubiquitous, however. Interpreting unfamiliar symbols, especially those that request user input, can sometimes require assistance from an external database such as Apple Support.
Some icons can have multiple meanings depending on your specific circumstances. One such icon depicts a folder with an exclamation mark next to it. This symbol may appear for a number of reasons. If it appears when your iPod is connected to a computer, it means your device needs to be reformatted. It may also indicate that the iPod's battery is low and needs to be recharged. If your device becomes unresponsive and this symbol appears, it means that the iPod has locked and needs to be restored.
Several icons may appear to indicate a problem with your iPod's battery. A battery with an exclamation mark next to it means that the iPod is almost out of battery life. In place of this icon, newer iPods may display a text message informing you that no battery power remains and requesting that you connect the iPod to a power source. If you connect your iPod to a computer when the battery is completely drained, it will need to charge for several minutes before information can be exchanged. During this process, a monochromatic battery icon with a lightning bolt next to it may appear.
Some icons appear to give you instructions regarding when it is or is not safe to perform certain actions. For example, when your iPod is connected to your computer and in the process of managing or transferring music or other data, the no symbol -- a circle with a diagonal line through it -- appears with a caption beneath it that reads, "Do not disconnect." This icon will remain until the iPod has completed the transfer, at which point the no symbol will disappear and the text will change to read, "OK to disconnect."
An icon of a disk with a magnifying glass above it will appear if your iPod discovers a problem with its hard disk and requires a disk scan. Once the scan is complete, one of several icons may appear. A disk with an exclamation mark means that the scan failed. A disk with a check mark indicates that the scan found no problems. A disk with an arrow means that a problem was found and has been corrected. Finally, a disk with an X appears if the scan is cancelled by you before completion.