I know CMR vs SMR but what is HM/DM?

Also, I have a couple of those “Max Digitsl Data” drives, 4 & 10TB. Do you happen to know which those are?

What I meant, and perhaps I have a misunderstanding, is that I was under the impression that SSL could be configured such that it behaves in the way that’s widely known - either a website is “trusted” because an authority has verified that the true owner owns it within a certain period of time - but also as second method more akin to SSH keys, wherein the server has one certificate, the client has a signed cert, and you can only access the server if you’re in possession of a signed certificate on the device being used to access the site. This digicert description matches mine, so I don’t think I’m too far off but I’m missing something

I’m not asking from a knowledgeable position, so bear with me if it’s a dumb question: Why don’t people use client certificates for this and restrict access to only clients with the certificate? It seems about as a VPN, and also is revocable, and a time expiry can be put on (I suppose that’s the case with VPNs too). They seem like rather similar solutions but I only see VPNs suggested