Your uncle sends you an email message. He is shopping on the internet, looking at drives because he needs storage for his large photo collection. He doesn't want to back it up to "that cloud". He doesn't trust that cloud. He is trying to choose between SSD and hard drives. He needs about 350gb. He doesn't understand why one type is so much more expensive than the other and he'd like you to explain the difference and recommend which type he purchase. He wants to understand the technology. What do you tell him?