A RAM Disk is a block of memory that can be accessed as a disk device. Due to the nature how RAM works, its contents is gone after reboot or shutdown. This means anything you store on a RAM disk is gone after a reboot. It is by design and it may or may not be desired behaviour.
Image files are used to overcome this behaviour. An image file is a regular file on a HDD, that is read into a RAM disk to populate it with contents. Likewise, before the system restarts the contents of a RAM disk can be saved to an image file to preserve user data between sessions.
In order to create an image-backed RAM disk:
- Choose Image - Create Image from the main menu and save the image on your hard drive.
- Choose Disk - Add Boot Disk and specify the image file created in step 1.
- Tick Save Contents to Image.