Galaxy S21 Tips

When an app needs to be absolutely sure it won't be cleared from RAM by Android's memory management system, it posts a persistent, ongoing notification. Another time you'll encounter non-removable alerts is when your phone or carrier really wants you to do something, like apply an update.

Codecs are like ZIP archives for media files. Rather than storing an entire analog sound file, the digital version is compressed to save space. The algorithm used to reduce file size is called a codec, as it encodes to digitize and decodes when it's time to play the file back. So as you can imagine, a better codec can lead to drastically improved sound quality.