Using your RAM Disk software is it possible to create a RAM disk at boot-up prior to the operating system starting, mount an SSD, copy the operating system to the RAM disk, and then boot the operating system from RAM as in the old DOS days?
If it is the only operating system that exits on your machine, it cannot be moved to a RAM disk because the RAM Disk software itself is installed on that system.
But if you are asking about booting an additional system, then because modern operating systems, such as Windows 10, have become much more complex, the process of directly copying them to a RAM disk and booting from there is not straightforward. However, you can achieve a similar effect and performance boost by using virtualization. You can create a virtual machine using virtualization software like VMware, VirtualBox, or Hyper-V. Then you can configure the virtual machine to run from a RAM disk. This means that the virtual machine's virtual hard disk (VHD or VMDK) will be stored in RAM instead of a physical drive, allowing for faster access times.
Keep in mind that running an entire operating system from a RAM disk has its requirements. You will need a sufficient amount of RAM to accommodate the operating system and its applications. Additionally, any changes made during the session will not persist across reboots unless you have a separate storage mechanism to save those changes.