It might not have been the booming industry it is today but patent trolls existed in the 80s, too. Here's John Walker, one of the founders of AutoDesk, writing in 1993:
“Ever since Autodesk had to pay $25,000 to ``license'' a patent which claimed the invention of XOR-draw for screen cursors (the patent was filed years after everybody in computer graphics was already using that trick), at the risk of delaying or cancelling our Initial Public Offering in 1985, I've been convinced that software patents are not only a terrible idea, but one of the principal threats to the software industry.”
I believe the XOR patent was the first major one, and certainly the most blatant troll – it hit most of the industry for a technique which had been described a decade before filing – but the software patent mess started arguably in 1981. Wikipedia has timeline of the evolving caselaw:
“Ever since Autodesk had to pay $25,000 to ``license'' a patent which claimed the invention of XOR-draw for screen cursors (the patent was filed years after everybody in computer graphics was already using that trick), at the risk of delaying or cancelling our Initial Public Offering in 1985, I've been convinced that software patents are not only a terrible idea, but one of the principal threats to the software industry.”
http://www.fourmilab.ch/autofile/www/chapter2_105.html