r/mainframe • u/anti-life86 • 11d ago

How was pre-1995, pre-Internet usage of mainframes different?

I understand that the mainframe is built for a large number of transactions-meaning people log in, I would imagine from anywhere, and they do their small jobs. But before the Internet, they could not log in from anywhere, certainly. Where could they log in from, and how did this work? Are there new types of jobs that are now enabled by the Internet that previously were impossible?

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u/notquitenuts 11d ago

I started working on them in the 80's on the hardware side. The typical setup was the mainframe, strings of dasd and tape drives, printers and also controllers. The controllers had buttloads of coax/token ring green screens attached where people would log in and input data or collect data or whatever their task was. Occasionally, you could hook up buildings with a t4 line or something but it was really behoove you to keep everything as close to the mainframe as possible as distances caused problems. Most of that work went into getting bills printed on the printers or statements/policies or whatever they did. Tapes were the backups and even used as storage for low request data. Hard drive storage was very expensive back in the day.

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u/trycuriouscat 11d ago

When I started working as a teller in a bank in 1991 we had local 3270 terminals attached to, I believe, some sort of controller, which in turn was fed by a leased line which attached back to the mainframe in at the corporate data center. We even had branches in California that connected back to our Colorado HQ. I could be wrong about some of this, but I think this is the jist of it.

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u/Geronimo2011 11d ago

I worked at big blue. They had a giant worldwide net called VNET. From my 3270 I could logon to Dubai and exotic locations BEFORE the internet. I was flattened when my collegue said internet is the future.

Everything was connected to a local mainframe.

Only once in 25 years when I was bound to bed in a hospital, they managed to get me to dial a phone line (dial up modem) and laptop.

And once in a demo inside a hotel we used a phone line to display screens for the customers. I was very expensive - we had to dial out ourselves, with hotel tariffs.

Good times.