Virtual machine and cloud system software

A virtual machine (VM) is a software-based computer that exists within another computer’s operating system, often used for the purposes of testing, backing up data, or running SaaS applications. To fully grasp how VMs work, it’s important to first understand how computer software and hardware are typically integrated by an operating system.

"The cloud" refers to servers that are accessed over the Internet, and the software and databases that run on those servers. Cloud servers are located in data centers all over the world. By using cloud computing, users and companies don't have to manage physical servers themselves or run software applications on their own machines.

The cloud enables users to access the same files and applications from almost any device, because the computing and storage take place on servers in a data center, instead of locally on the user device. This is why a user can log into their Instagram account on a new phone after their old phone breaks and still find their old account in place, with all their photos, videos, and conversation history. It works the same way with cloud email providers like Gmail or Microsoft Office 365, and with cloud storage providers like Dropbox or Google Drive.

For businesses, switching to cloud computing removes some IT costs and overhead: for instance, they no longer need to update and maintain their own servers, as the cloud vendor they are using will do that. This especially makes an impact on small businesses that may not have been able to afford their own internal infrastructure but can outsource their infrastructure needs affordably via the cloud. The cloud can also make it easier for companies to operate internationally because employees and customers can access the same files and applications from any location.

Several cloud providers offer virtual machines to their customers. These virtual machines typically live on powerful servers that can act as a host to multiple VMs and can be used for a variety of reasons that wouldn’t be practical with a locally-hosted VM. These include:

• Running SaaS applications - Software-as-a-Service, or SaaS for short, is a cloud-based method of providing software to users. SaaS users subscribe to an application rather than purchasing it once and installing it. These applications are generally served to the user over the Internet. Often, it is virtual machines in the cloud that are doing the computation for SaaS applications as well as delivering them to users. If the cloud provider has a geographically distributed network edge, then the application will run closer to the user, resulting in faster performance.
• Backing up data - Cloud-based VM services are very popular for backing up data because the data can be accessed from anywhere. Plus, cloud VMs provide better redundancy, require less maintenance, and generally scale better than physical data centers. (For example, it’s generally fairly easy to buy an extra gigabyte of storage space from a cloud VM provider, but much more difficult to build a new local data server for that extra gigabyte of data.)
• Hosting services like email and access management - Hosting these services on cloud VMs is generally faster and more cost-effective, and helps minimize maintenance and offload security concerns as well.