
Microsoft is an historical name in the IT world, both in the consumer and the professional area.
Actually it’s already a player in the storage world: just consider the Windows Storage Server edition included in some storage appliances (for example the Dell PowerVault NX family). But Windows Storage Server is little more than an “embedded” version of Windows Server and basically is just a dedicated Windows Server (with a better license cost than the full edition).
An enterprise storage is just more than this and must provide more functions, but first to all an high availability configuration (and possibly also a scalable solution).
Starting with Windows Server 2012, Microsoft has introduced lot of storage related features including SMB3, de-duplication, a new filesystem for huge volumes (ReFS) and storage spaces. And with Windows Server 2012 R2 also a multi-tiering. Actually Storage Spaces with Tiering is something really close and comparable with enterprise storages and Windows Server could be (loosely) presented as a Software Defined Storage solution.