General Science, Mathematics, and Technology
What are some newer forms of portable storage media?
External hard drives are similar to the internal hard drive of the machine with storage capacity of up to and beyond 2 TB. Often using a USB port to connect, they provide an easy alternative for backup storage.
Compact discs (CDs) and DVDs are optical storage devices. There are three types of CDs and DVDs: read-only, write-once (CD-R and DVD-R), and rewritable (CD-RW and DVD-RW). Although readonly CDs and DVDs are wonderful for prepackaged software, they do not permit a user to save their own material. CD-Rs store 700 MB of data and can be written once. DVD-Rs are similar to CD-Rs except they hold 4 to 28 times more data. Single disc DVD-Rs are available that can store 4.7 GB of data or two hours of video. Read/write CDs use a different chemical compound which allows data to be recorded, erased, and re-written.
Solid state storage technology has no moving parts. One example is flash memory sticks. All cells are set to 0 on the memory chip before data is stored in a flash memory stick. When data are entered, electric charges are applied to certain cells. These charges pierce a thin layer of oxide and become trapped. The trapped charges become 1s. The binary code pattern of 0s and 1s is stored into the memory. Flash memory sticks are available with up to 64 GB of storage providing large amounts of easily transportable storage.