In 1989, I developed a fairly complex Electronic Product, which had a keyboard, a programmable memory and a 7segment digital display, and did not use any form of microprocessor, but a fixed logic circuit, and also had the ability to invalidate a card if it was lost or stolen, and segregate cards if they were assigned to a different machine, and stored data against that card user, the machine had 3 separate boards, I named them as a PSU Board, and code Board, and a Main Board, and each were interconnected with insulation displacement Molex connector system, proud to say that this machine is still being manufactured and is still in demand and was copied by another company whom I never sued! They sold well over 5000 machines at a cost of approx well over £500 each.
I remember how I had started this project back in 1986, and finally reached the latest design stages in 1989, whilst doing a full time job as well, and I had to use special acetate roll of paper on which i laid the printed circuit board layout, painfully slowly, using printed circuit board artwork tapes that came in various widths, starting with 1mm wide, 1.5mm and went all the way up to 10mm wide, and same for round solder pads that came on spools in different diameters, I had to peel each one off with a scalpel and place on the grid very accurately, using a 0.1 grid paper and did this art work at twice the real size, which was then photographically reduced and printed circuit boards were then manufactured from it.
Back then there were no computers available generally and I acquired my first proper computer in 1991 and bought a printed circuit board layout software from RS Components called EasyPc, and it worked on DOS, and I still use this today and it can still run on many modern computers up to Windows XP.
I can produce professional quality single sided PCs in about an hour from this EasyPC layout package to printing it on a clear film on laser printer and then
using positive photo resist boards to expos and etch boards and then drill on a bench drill to about 0.7mm diameter hole manually.