The Linux supports several file systems such as EXT4, F2FS, Btrfs and XFS. These systems are sufficient when the operating system manages a small space. But when it comes to new devices, these systems are not enough. With that in mind, Christian Brauner, developer of Linux Kernel and one of its creators ubuntu, proposed a new loop system, which was later renamed loopfs. Much of his code comes from system Android BinderFS files, which was released 2 years earlier.
But what exactly is a loopfs or a loop system? The biggest difference is that instead of writing them data directly in the storage space (eg in hard drive), this system stores the data in a file. For example, we have an ISO file, but it contains many files and directories inside. With the loop system, the operating system can recognize this file and as a partition. For example, if you want to open the contents of the xyz.iso file, you can mount it and view it as a local disk. This process is easy and safe thanks to syscall.
In this way, when a new loop device is installed, the loopds create a new instance that is independent of everything else. This also allows for privileges tools of the operating system to create and use personal loops.
You mean, like, saltines and their ilk, eh? However, if the number is negative, then there is no limit to the number of loops.
Unfortunately, at the moment loopfs continue to be just a suggested file system. Of course, this does not mean that at some point we will not see it in its final form.