Everyone is talking about the cloud, but the term has a plethora of meanings. From a consumer’s point of view, the cloud is a Web service accessed by an app running on a smart phone or tablet. To a chief technology officer, it might be software-as-a-service (SaaS) or a way to run a horde of virtual machines.
To an embedded developer, the cloud is a target platform, a component within a cloud-based solution, and even a development platform. You might know how all these technologies work as well as their implications, but more likely some will remain a mystery.
Using the cloud
Anyone can use the cloud. Apple’s iCloud will not be the first service for storing a range of content, but its support for Apple’s iPhone and iPad instantly gives it a large audience. Dropbox is one of many services that work with any PC, tablet, or smart phone.
It’s even possible to implement cloud storage with your own network storage devices (see “Cloud Storage Delivers Reliability And Accessibility” at electronicdesign.com). Ctera provides a variety of network storage devices that use the cloud to tie them to myriad gadgets, from PCs to smart phones (Fig. 1).
SaaS is another way to use the cloud. It moves apps from running on a local platform onto the cloud. SaaS services can run on dedicated hardware, but typically utilize the cloud.
Running on the cloud
Cloud computing typically takes advantage of networking, virtualization, and iSCSI storage-area networks (SANs). Amazon’s Elastic Compute Cloud (EC2) and Google Cloud Services provide a very large and public collection of services distributed throughout the world and support everything from a single virtual machine (VM) to thousands of VMs.
The public cloud has a host of issues users need to consider, such as security and monitoring capabilities. Service level agreements (SLAs) are part of the mix, and high-availability support is optional. The advantage is that hardware purchases aren’t required.
Many users aren’t interested in tossing their server farms, though. The private cloud provides many of the advantages of the public cloud but with more control. Many companies are employing a mix of private and public services.