Applications that run on OpenVMS tend to be really important and have been in continuous operation (including upgrades where new ISA's were introduced) for deca

Applications that run on OpenVMS tend to be really important and have been in continuous operation (including upgrades where new ISA's were introduced) for decades. It was ported to Itanium and missed out on taking advantage of the 64-bit x64 wave. As Intel has moved high end reliability features to the Xeon line OpenVMS applications can be moved over to modern hardware. It's not so much that it's relevant to everyone, but it's a super interesting topic watching it get ported.