Primary storage is fast and non permanent, while secondary storage is slower, but more permanent.
Hard disk -- this is the most common method for storing information. Access time is relatively quick, and the data is relatively permanent. Hard drives can store a very large quantity of data. Hard disks do crash, though.
Floppy disk -- this is a slow method for storing data. It can be useful for making backup copies of small files, since the capacity of the disks are very small. They are also becoming obsolete, with many new computers not even containing them.
RAM -- extremely fast memory. The information is RAM is cleared everytime the power in the computer is turned off, so it is not permanent. It is fast, so it is used for running programs in real time. When a program is loaded, it typically gets loaded into RAM.
CD ROM -- you cannot write data to a CD-ROM, but it is somewhat permanent. It can store a large amount of data, and is a very common medium, so it can be used by everyone. Most software nowadays comes burnt onto CD-ROM's, since they have enough room, and the transfer rate is high enough to install large programs onto a computer quickly.
Tape -- this is an old storage device. Tape is great for making backups of large amounts of data. However, it is extremely slow, so it should not be used for real time access. Instead, tapes can be stored and used in the case of a failure of a hard drive.
Zip Disk -- this format has become obsolete over the past few years. They were similar to floppy drives, in that they are somewhat slow, and their storage capacity is limited. They would be useful for making backups.
CD Read/Write -- similar to CD-ROM's, this can store a large amount of data. It is easy for computer users to make their own CDs, allowing them to be used for backing up data. As with CD-ROM's, they can be read by most computers.
Let me know if you have any questions,