It's not Linear A. The script, if it is properly a script, which people still argue about to some degree, is often called the "Phaistos script" because there aren't any other known inscriptions that are indisputably from the same writing system. It could be related to the sequence of Minoan scripts (Minoan Hieroglyphics/Linear A/Linear B) but the relationship is unclear. Some scholars think it may be of Anatolian origin, which could explain why it doesn't fit so well into the Minoan script tradition.