Secondary storage is a type of storage of a computer system that is typically used for permanent storage of information- hence it is typically not volatile. There are three different types of secondary storage: optical, magnetic and flash/solid state.
Optical secondary storage involves secondary storage devices such as CDs, DVDs and Blu-Ray disks. They have access speeds of 7-16MB/s- slow relative to most magnetic devices. They all have a very low price for the amount they store. DVDs alone can store 4-17GB of information.
Magnetic secondary storage involves cassette tapes (or other product of magnetic tape), hard disk drives (the most popular method of permanent information storage on computer systems), floppy disks and more. Hard drives have very fast access speeds of 0.5-3GB/s- but magnetic tape don't. They typically store up to 1TB of information.