Cloud computing is the on-demand availability of computer system resources, especially data storage and computing power, without direct active management by the user. The term is generally used to describe data centres available to many users over the Internet. Large clouds, predominant today, often have functions distributed over multiple locations from central servers. If the connection to the user is relatively close, it may be designated an edge server.

Clouds may be limited to a single organization (enterprise clouds),or be available to many organizations (public cloud).

Cloud providers typically use a “pay-as-you-go” model, which can lead to unexpected operating expanses if administrators are not familiarized with cloud-pricing models.

The availability of high-capacity networks, low-cost computers and storage devices as well as the widespread adoption of hardware virtualisation, service oriented architecture and autonomic and utility computing has led to growth in cloud computing. By 2019, Linux was the most widely used operating system, including in Microsoft’s offerings and is thus described as dominant.The Cloud Service Provider (CSP) will screen, keep up and gather data about the firewalls, intrusion identification or/and counteractive action frameworks and information stream inside the network.

Cloud computing exhibits the following key characteristics:

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• Agility for organizations may be improved, as cloud computing may increase users’ flexibility with re-provisioning, adding, or expanding technological infrastructure resources.
• Cost reductions are claimed by cloud providers. A public-cloud delivery model converts capital expenditures(e.g., buying servers) to operational expenditure.This purportedly lowers barriers to entry, as infrastructure is typically provided by a third party and need not be purchased for one-time or infrequent intensive computing tasks.
• Device and location independence enable users to access systems using a web browser regardless of their location or what device they use (e.g., PC, mobile phone). As infrastructure is off-site (typically provided by a third-party) and accessed via the Internet, users can connect to it from anywhere.
• Maintenance of cloud computing applications is easier, because they do not need to be installed on each user’s computer and can be accessed from different places (e.g., different work locations, while travelling, etc.).
• Multitenancy enables sharing of resources and costs across a large pool of users thus allowing for:
  • centralization of infrastructure in locations with lower costs (such as real estate, electricity, etc.)
  • peak-load capacity increases (users need not engineer and pay for the resources and equipment to meet their highest possible load-levels)
  • utilisation and efficiency improvements for systems that are often only 10–20% utilised.
• Performance is monitored by IT experts from the service provider, and consistent and loosely coupled architectures are constructed using web services as the system interface.
• Productivity may be increased when multiple users can work on the same data simultaneously, rather than waiting for it to be saved and emailed. Time may be saved as information does not need to be re-entered when fields are matched, nor do users need to install application software upgrades to their computer.
• Reliability improves with the use of multiple redundant sites, which makes well-designed cloud computing suitable for business continuity and disaster recovery.
• Scalability and elasticity via dynamic (“on-demand”) provisioning of resources on a fine-grained, self-service basis in near real-time(Note, the VM startup time varies by VM type, location, OS and cloud providers, without users having to engineer for peak loads).
• Security can improve due to centralization of data, increased security-focused resources, etc., but concerns can persist about loss of control over certain sensitive data, and the lack of security for stored kernels.  

Security and privacy

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Cloud computing poses privacy concerns because the service provider can access the data that is in the cloud at any time. It could accidentally or deliberately alter or delete information. Many cloud providers can share information with third parties if necessary for purposes of law and order without a warrant. That is permitted in their privacy policies, which users must agree to before they start using cloud services. Solutions to privacy include policy and legislation as well as end users’ choices for how data is stored. Users can encrypt data that is processed or stored within the cloud to prevent unauthorized access.

But the systems work by creating and describing identities, recording activities, and getting rid of unused identities.

Limitations and disadvantages

According to Bruce Schneier,”The downside is that you will have limited customization options. Cloud computing is cheaper because of economics of scale and—like any outsourced task—you tend to get what you want. A restaurant with a limited menu is cheaper than a personal chef who can cook anything you want. Fewer options at a much cheaper price: it’s a feature, not a bug.”

In cloud computing, the control of the back end infrastructure is limited to the cloud vendor only. Cloud providers often decide on the management policies, which moderates what the cloud users are able to do with their deployment. Cloud users are also limited to the control and management of their applications, data and services.

Cloud computing is beneficial to many enterprises; it lowers costs and allows them to focus on competence instead of on matters of IT and infrastructure. Nevertheless, cloud computing has proven to have some limitations and disadvantages, especially for smaller business operations, particularly regarding security and downtime.