We will start reviewing file system trends in Linux. This is relevant because there is newer demand from cloud computing that the traditional file system did not anticipate. While we will be reviewing a paper from wisc.edu titled "a study of linux file system evolution"  which features eight years of linux file system changes across thousands of patches, we find relevancy in emerging trends in cloud computing. For example, on one hand, organizations are building low footprint linux operating system and container framework on top and on the other hand, cloud operating systems such as OSv is emerging where the OS kernel involving threads, processes and drivers are removed from the Virtual Machine. Finally, users are being asked to forget about management chores and offload it to managed services from the cloud for their files. Replication and backup are now part of the offerings from these cloud managed services. Moreover, file systems are also being stretched over clusters as in the case of OneFS and at the same time traditional file system protocols are improving usages
One of the common themes seen in these emerging trends is the applicability of a general purpose platform versus a specialized product or service. Cloud operating systems are designed to run a single application within a single virtual machine. This means a general purpose operating system is no longer necessary. The runtime that the application requires is difficult to be ported to different hardware environment but manageable to be ported to hypervisors. This is what the cloud operating systems propose. A single kernel and application image is then termed a "unikernel" Windows "picoprocess" framework via DrawBridge and Xen via OSv are some examples.
Cloud Operating Systems do not necessarily compete with Linux.  Xen for example is still Linux. Linux has a wide hardware support and continues to have dominance in cloud computing. All that the Cloud Operating Systems propose is to remove layers of the software stack improving performance and security.Xen is popular for its Paravirtualization - a term used to refer to the simple and idealized interface for I/O to the guest. While Xen provides hypervisor technology, it is also trying to come out with its own version of cloud operating system called MirageOS which it refers to as exokernel.