I just finished watching for the first time ever, George Lucas's THX-1138 released in 1971. I was curious about it, so I recorded it recently off TCM.  Did not care much for it. 

But there's a scene toward the end where the characters are running about what appears to be a data center, set up not unlike what data centers look like now (rows and rows of racks and racks)!  I found that very interesting.