Supported file systems include NTFS, FAT32, EXT2 and EXT3. It can be installed on internal memory, but that may pose some unnecessary risk.
Instructions for installation recommend installing Remix OS to a FAT32 formatted USB drive that supports the USB 3.0 standard and has at least 8GB of storage available.
I believe it is Lollipop, and a Marshmallow version is likely to be available soon, as an install or an update. It’s not entirely clear whether the Alpha version of Remix OS currently available from the Jide Website is based on Lollipop or Marshmallow. The stable version of Android x86 from the project Website is based on the Lollipop (5.1). Jide manufactures a couple of devices that run on Remix OS, but they recently decided to make Remix OS available free to anyone who wants to download and install it. It is a somewhat more polished version called Remix OS for PC with point and click capabilities, making it more like using a PC or a Mac. Jide, a company started by some ex-Google engineers, has partnered with the Android x86 project and branded their own version of Android x86. The project is called, not surprisingly, the Android x86 project. For years, an open source project has been working on porting the Android operating system to the x86 platform… meaning, it can be run on PC hardware with an Intel or AMD processor.