Yes I know what that is. I have run virtualization pools for major corporations. I have an ESXi box in my office. I've been doing virtualization since long before it was cool.
I hopped on with the announcement of Xen, sometime after Bochs went open source. I suspect I may have used bochs before it went open source.
I'm throwing that out there because I'm not sure
which time you're talking about virtualization being cool. Do you mean the 2010s? The early 2000's? Back in the 60's when IBM was developing it on System whatever the fuck it was?
I'm talking early 1999, 2000s, but while I wrote articles about it and even played a bit with qemu ...I didn't actually get the full monty experience until 2007. Regardless yeah -I watched it coming, granted as a desktop user and not as some sort of luncheon-attending professional.
In the beginning was the POSIX subsystem. Softway extended it for wider UNIX support and making it talk to Win32 with fewer of Microsoft's restrictions. WSL1 extended it and moved more of the system calls into the POSIX subsystem. It's not a different thing from WSL1, it's just an older version.
In the beginning was the decision to split the NT kernel into personalities; win32, os/2 and
then later posix. That's the origin of the entire 'subsystem' concept. It probably has something to do with cutler and wank wank vms wank wank wank. But that's the beginning; when they were planning the next version of os/2 (which became NT) and they brought Culter in.
WSL1 is a subsystem -, a personality similar to the mostly-neutered os/2 subsystem (yes, I know that was taken out in windows 2000 or so -that's beside the point).
WSL2 ...is a virtual machine, distinct from a subsystem (though both work on a kernel level, with the difference being that WSL2 uses the kernel's hardware virtualization features instead of being a ui personality/subsystem). The primary difference from something like qemu/kvm is that the UI to WSL2 is a metric fuck-ton better if for no other reason than the integration into windows terminal.