Cloud Computing

Cloud computer services are computer resources that are accessed remotely, via the Internet, but which were once commonly accessed locally. The cloud can be divided into cloud storage, in which customer files or other data are stored remotely, and cloud computing, involving remote processing. A common characteristic of the latter category is that the provider’s resources are shared dynamically among different customers; this distinguishes cloud computing from simple leasing of physical web servers (see below at Cloud Models). Use of the cloud can mean reduced risk of data loss, reduced upfront investment costs, and simplified software setup; the cloud has, for example, made it easier to launch high-tech companies by reducing startup costs. On the other hand, cloud users must ensure that they understand the privacy and security implications of the cloud and their agreement with the cloud provider.

Cloud-based resources can vary considerably. Cloud storage may involve storing very large files, such as video, or relatively small files, such as calendar entries. Cloud computing may involve remote databases, web servers and other application servers, or general-purpose computers that are configured by the customer as desired.

Cloud-based services are most often offered by a third party, in which case they are classed as the public cloud. Alternatively, a site can maintain its own private cloud; private cloud services can also be leased. While a self-maintained private cloud means that the owning organization must still handle all the hardware and lower-layer software issues that are avoided by public cloud users, there can still be significant cost savings due to scale, resource sharing, and the standardization of basic hardware building blocks.

Cloud services can be offered from a single site or from a geographically distributed set of sites. Many cloud storage providers offer limited personal accounts free of charge, though such accounts rarely have much access to technical support. Business use almost always requires a paid account, together with a very clear understanding of the terms of service.

The most basic form of cloud services is cloud storage. The issue of privacy is usually important, as the cloud provider has access to the customer’s content, as discussed below. For large files, such as media files, cloud storage is often done simply because sufficient local storage is not available. For smaller files, cloud storage offers the safety of a secure backup; many mobile device owners have been greatly relieved to discover, after losing their device, that many of their files and records were easily restorable from the cloud. Cloud storage also allows sharing of files or data between multiple devices owned by one user; for example, video files downloaded onto a desktop computer might be uploaded to the cloud to allow viewing on a mobile device, or messages and calendar entries may be synchronized between multiple devices. Finally, files may be uploaded to the cloud to enable sharing between different users. Particularly for media files, this may lead to copyright issues, mentioned later in this entry. It often also raises additional privacy questions about whether any users other than those intended have access to the shared files.

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