During 1982-1987 I sold lots of accounting systems on PCs, LANs and UNIX.
Some of the first to run on a new 'Local Area Network' or LAN OS called Novell and on the new generation of UNIX boxes sporting weird names like Zilog and the AT&T 3B2. But like the newly released IBM RISC box, running a multi-user accounting system at this level was risky as most of these systems went like a Corgi at a dog track.
One of the best multi-user operating systems at the time was Concurrent CP/M. I think it supported up to 4 users. On a good day.
So it was always a relief that stuff actually continued to work when more than 1 user logged on.
My goodness! You mean you can post a journal and inquire on an account balance at the same? Marvellous.
Selling the new LANs was difficult as there was substantial price difference between a dumb terminal and a PC so even the innovative 'user friendly' interface of say, Torus Icon, couldn't persuade many businesses to switch from terminal-server to LAN-based accounting.