Punched tapePunched tape or perforated paper tape is a form of data storage, consisting of a long strip of paper in which holes are punched to store data. Now effectively obsolete, it was widely used during much of the twentieth century for teleprintercommunication, for input to computers of the 1950s and 1960s, and later as a storage medium for minicomputers and CNCmachine tools.

Magnetic tape

Magnetic tape is a medium for magnetic recording, made of a thin magnetizable coating on a long, narrow strip of plastic film. It was developed in Germany, based on magnetic wire recording. Devices that record and play back audio and video using magnetic tape aretape recorders and video tape recorders. A device that stores computer data on magnetic tape is a tape drive (tape unit, streamer).

Magnetic tape revolutionized broadcast and recording. When all radio was live, it allowed programming to be recorded. At a time whengramophone records were recorded in one take, it allowed recordings to be made in multiple parts, which were then mixed and edited with tolerable loss in quality. It is a key technology in early computer development, allowing unparalleled amounts of data to be mechanically created, stored for long periods, and to be rapidly accessed.

Nowadays other technologies can perform the functions of magnetic tape. In many cases these technologies are replacing tape. Despite this, innovation in the technology continues and tape is still used.[when?]

Over years, magnetic tape can suffer from deterioration called sticky-shed syndrome. Caused by absorption of moisture into the binder of the tape, it can render the tape unusable.

Floppy disk

A floppy disk, or diskette, is a disk storage medium composed of a disk of thin and flexible magnetic storage medium, sealed in a rectangular plastic carrier lined with fabric that removes dust particles. Floppy disks are read and written by a floppy disk drive (FDD).

Floppy disks, initially as 8-inch (200 mm) media and later in 5¼-inch (133 mm) and 3½-inch (90 mm) sizes, were a ubiquitous form of data storage and exchange from the mid-1970s well into the 2000s.[1]

By 2010, computer motherboards were rarely manufactured with floppy drive support; 3½-inch floppy disks can be used with an externalUSB floppy disk drive, but USB drives for 5¼-inch, 8-inch and non-standard diskettes are rare or non-existent, and those formats must usually be handled by old equipment.

While floppy disk drives still have some limited uses, especially with legacy industrial computer equipment, they have been superseded by data storage methods with much greater capacity, such as USB flash drives, portable external hard disk drives, optical discs, memory cardsand computer networks

Compact disc

Compact disc (CD) is a digital optical disc data storage format. The format was originally developed to store and play back sound recordings only (CD-DA), but was later adapted for storage of data (CD-ROM). Several other formats were further derived from these, including write-once audio and data storage (CD-R), rewritable media (CD-RW), Video Compact Disc (VCD), Super Video Compact Disc (SVCD), Photo CD, PictureCD, CD-i, and Enhanced Music CD. Audio CDs and audio CD players have been commercially available since October 1982.

Standard CDs have a diameter of 120 millimetres (4.7 in) and can hold up to about 80 minutes of uncompressed audio or 700 MiB(actually about 703 MiB or 737 MB) of data. The Mini CD has various diameters ranging from 60 to 80 millimetres (2.4 to 3.1 in); they are sometimes used for CD singles, storing up to 24 minutes of audio or delivering device drivers.

At the time of the technology's introduction it had much greater capacity than computer hard drives common at the time. The reverse is now true, with hard drives far exceeding the capacity of CDs.

In 2004, worldwide sales of CD audio, CD-ROM, and CD-R reached about 30 billion discs. By 2007, 200 billion CDs had been sold worldwide.[1] Compact discs are increasingly being replaced or supplemented by other forms of digital distribution and storage, such as downloading and flash drives, with audio CD sales dropping nearly 50% from their peak in 2000.[2]

hard disk drive A hard disk drive (HDD)[b] is a data storage device used for storing and retrieving digital information using rapidly rotating disks (platters) coated with magnetic material.[2] An HDD retains its data even when powered off. Data is read in a random-access manner, meaning individual blocks of data can be stored or retrieved in any order rather than sequentially. An HDD consists of one or more rigid ("hard") rapidly rotating disks (platters) with magnetic heads arranged on a moving actuator arm to read and write data to the surfaces.

Usb driveA USB flash drive is a data storage device that includes flash memory with an integrated Universal Serial Bus (USB) interface. USB flash drives are typically removable and rewritable, and physically much smaller than an optical disc. Most weigh less than 30 grams (1.1 oz).[1]As of January 2013, drives of up to 512 gigabytes (GB) were available.[2] A one-

terabyte (TB) drive was unveiled at the 2013 Consumer Electronics Show and became available later that year.[3] Storage capacities as large as 2 TB are planned, with steady improvements in size and price per capacity expected.[4] Some allow up to 100,000 write/erase cycles, depending on the exact type of memory chip used, and a 10-year shelf storage time