As information is created on a computer, it is often saved for future reference or as part of a permanent record of a completed project. Today, a wide variety of computer storage options exist, and there continue to be great advances in this area. Currently the most popular storage sys­tems are:

• Hard drives
• Optical disk systems (CD and DVD Roms)
• Flash memory systems
• Cloud based services e.g. OneDrive, GoogleDrive, Dropbox

 Hard drives

A hard drive is a device that stores data mag­netically on metal disks that are permanently sealed. On many computers, the hard drive continues to serve the two functions for which it was created i.e. storing program information and storing user data. Internal hard drives hold be­tween 80 to 1000 GB, and that storage capacity is expected to grow.

Although hard drives are typically located inside the computer, external hard drives are also available. These devices are storage mechanisms that operate like an internal hard drive but con­nect to a computer using a USB port, a FireWire port, or a wireless networking connection. Ex­ternal hard drives can be used to move a large amount of data from one computer to another, as a backup hard drive, or as additional information storage. Because hard drives use magnetic re­cording, they are susceptible to the effects of minor bumps or careless handling that can affect the integrity of the stored data.

Portable hard drives are small devices used to move information from one computer to another. Typically, these small devices are designed to be used with handheld computers, digital music players, and other portable devices. Hard drives today come with built-in security features, such as fingerprint readers that allow only authorized users to access the information on the drive.

Optical disk systems

An optical disk is a thin, lightweight plastic disk that can be used to store and retrieve data with a low-powered laser beam. Many people are familiar with the first generation of optical disk storage, the compact disk (CD). Although CDs were originally created to store music and soft­ware, there has been a constant succession of optical disk formats. Second generation optical disk storage includes digital versatile disks (DVDs). This storage medium was created to store large amounts of data, including TV-quality digital video. The main enhancements from the CD to the DVD are that the DVD can be used to store high-quality video and sound data. DVDs resemble CDs in the way they look; however, they are encoded in a different format and at a much higher density.

CDs and DVDs come in a variety of formats. CD-ROMs (compact disk read -only memory) and DVD-ROMs (digital versatile disk read-only memory) are read-only storage media. This means that they can be read but no data can be added, changed, or erased. This media form typically comes pre-recorded with software programs, clip art, product demos, or music. Most CD-ROM drives can play data and audio CDs; DVD-ROM drives can play data and audio CDs and DVDs.

Recordable disks include CD-R, DVD-R, DVD+R, and DVD+R DL. A recordable disk is one that can be written to but the disk cannot be erased and reused. Recordable CDs are com­monly used for backing up files, sending large files to others, and creating custom music CDs. Recordable DVDs are used for similar purposes or when more storage space is needed such as for large backups or for storing home movies or video files. Rewritable disks are also available. These disks can be recorded on, erased, and overwritten. The most common types of rewrit­able optical media include CD-RW, DVD-RW, and DVD+ RW disks.

A variety of third generation blue laser disks (BDs) are currently in development. Using a blue laser instead of infrared lasers (CDs) or red lasers (DVDs), the new optical disks are designed for storing high-definition video and support larger storage capacities. Although there are a variety of third generation disks still in devel­opment, the Blu-ray Disc (BD) and HD- (high density) DVD are two examples of third gener­ation disks currently on the market.

Optical disks offer a number of advantages over traditional magnetic storage media. First, an optical disk holds much more data. Because there is greater control and focus possible with laser beams, much more data can be written into a smaller space. Also, storage capacity increases with each new generation of optical media. For example, a BD can store five to six times the amount of data than can currently be stored on a DVD; the HD-DVD can store three times the data of a standard DVD. Optical disks are also inex­pensive to manufacture, and data stored on them is safe from most environmental threats such as magnetic disturbances and power surges.

Flash memory systems

Flash memory is a type of non-volatile memory where data can be electrically stored, retrieved, and erased. Non-volatile memory can retain stored information even when there is no power. What makes flash memory systems different from hard drives and optical disk technology is that they are a solid-state storage system, mean­ing they have no moving parts. Because of this, flash memory systems require much less power than conventional drives and are resistant to shocks and vibrations.

Flash memory usually takes on one of two forms: cards or drives. Flash memory cards are small cards that are inserted into computers or other portable devices for storage purposes. Flash cards come in a variety of formats. A flash drive is a portable storage device that typically connects to the USB port on a computer. A flash drive, also known as a mini drive, jump drive, keychain drive, pen drive, or thumb drive, is typically the size of a package of gum or smaller.

The small size of flash memory devices make them an excellent storage medium for digital cameras, digital music players, handheld computers, notebook computers, smartphones, and other portable devices. This small size also makes them an excellent method for transporting data from one place to another in a briefcase or pocket. Flash memory media are rewritable and have a longer expected life than other removable media.

Cloud based services

Data can be stored using a cloud-based service such as OneDrive, GoogleDrive, and Dropbox.  The cloud is a network of computers with storage capabilities allowing data to be accessed from anywhere at any time.   The advantage of storing data using a cloud-based service not only allows an organisation to access their documents from anywhere, it also save them money and time.