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Incomputing, aremovable media is adata storagemedia that is designed to be readily inserted and removed from a system.[1] Most early removable media, such asfloppy disks andoptical discs, require a dedicatedread/write device (i.e. adrive) to be installed in the computer,[2] while others, such asUSB flash drives, areplug-and-play with all the hardware required to read them built into the device, so only need adriver software to be installed in order to communicate with the device.[3] Some removable media readers/drives are integrated into thecomputer case, while others are standalone devices that need to be additionally installed or connected.
Examples of removable media that require a dedicated reader drive include:
Examples of removable media that are standaloneplug-and-play devices that carry their own reader hardwares include:
Using removable media can pose somecomputer security risks, includingviruses,data theft and the introduction ofmalware.[6]
The earliest form of removable media,punched cards andtapes, predates the electronic computer by centuries, with theJacquard loom of 1801 using interlinked cards to control the machine.[7] This followed a loom made byBasile Bouchon in 1725 that used paper tape for its instructions.[8] Punched tape was later used inColossus, the first electronic computer.[9]
Magnetic tape was developed in the early 20th century in Germany, based onmagnetic wire recording invented byValdemar Poulsen in 1898.[10] In 1951, theUNIVAC I was released, using magnetic tape to store data.[11] 8-inchfloppy disks were commercially introduced in 1971 byIBM,[12] with them being compacted to5+1⁄4-inch by Shugart Associates in 1976.[13] At the same timeCompact Cassettes started being used to store data, being popular in the late 1970s and 1980s for holding data forpersonal computers.[14] In 1982, the3+1⁄2-inch floppy disk became commonplace, with its introduction for theApple Macintosh andAmiga.[15]
TheCD-ROM was introduced in 1985, providing much higher capacity than a floppy disk, however could not be written to. This was resolved in 1990 with the introduction of theCD-R.[16][17] TheCD-RW, introduced in 1997 allowed the CD to be written to multiple times, rather than just once, as with the CD-R.[18]DVD versions of these formats introduced in the late 1990s provided further increases in capacity.[19] Additional capacity improvements were achieved withBlu-ray in 2006.[20]
The turn of the millennium saw the widespread introduction ofsolid-state removable media, with theSD card being introduced in 1999, followed by theUSB flash drive in 2000.[21] The capacity of these removable flash drives improved over time, with 2013 seeingKingston unveiling a 1terabyte USB flash drive.[22]
Storage is intended to be used to access data that is access less often. Memory on the other hand is used to access data that is used on a more frequent basis. One of the problems with the earliest computers was how to store data. In the 1950s theInternational Business Machines (IBM) was trying to solve this problem.[23]
The first floppy disk was developed under the supervision ofAlan Shugart in the late 1960s. The floppy disk was not introduced to the public until the 1970s by IBM. But, like any man-made product the floppy disk came with its pros and cons, such as it being cheap and portable while also having severely limited data storage.[citation needed]
The use of removable media creates a risk of data loss in the event that the media is lost or stolen. This can lead to the compromise of large amounts of sensitive data, which can result in significant damage to the reputation of a business, as well as possible financial penalties.[24] This risk can be minimised by company policies that reduce the use of removable media when transporting and storing data, and by encrypting the contents of removable media. Prior to the disposal or reuse of removable media, appropriate steps should be taken to ensure that all data previously stored on the device is not accessible.[6] Additionally, any device holding sensitive data should be kept secure when not in use.[24]
Removable media can also be used as avector for malware. Attackers generally usesocial engineering to get someone to put a media device into a computer, for example by leaving an infected drive in a busy location, from which someone may pick up the device and put it into their computer to find its contents, such an attack is known as baiting. Once the device has been plugged in it can be used to infect an entire network. One example of malware that propagates through removable media such as USB flash drives isStuxnet, which caused significant damage toIran's nuclear program. The risk from an attack like this can be reduced by automatically scanning media for malware and prohibiting users from attempting to access the contents of removable media of unknown origin.[6][24]