Hi Beeza,
I managed a VAX/VMS cluster in late 1987, and then OpenVMS on a DEC Alpha from around 1995 at Heriot-Watt University in Edinburgh. I implemented a system for managing VMS accounts in 1988, which really needed a database. Since we had no budget for this I used ISAM (Indexed Sequential Access Method) files to make a "poor man's database".

VMS ISAM files were configured through a command interface, and later with an editor accessing Record Management Services (RMS) facilities. Records were fixed-length, but could have many keys. The indexes and data records were in the same file.

I remember being shocked that there was nothing similar in Unix as we moved away from VMS, and then I discovered PostgreSQL...