"And 60% seemed fair, since the idea was that the company would be providing health insurance, paying for the production of the goods, and handling shipping and related customer service," he wrote.
"And when my daughter was born and needed surgery and continuing medical attention I could hardly jeopardise our insurance in the days before the ACA. I was between a rock and a hard place like many residents of the US."
Since then, he said, the store had stopped providing any benefits, "and shouldn't even be getting a 50/50 split in my opinion, much less looting the coffers for 81+% (anything they want to spend money on is an expense, apparently, while any expenses I have to support the actual project come out of the peanuts they toss me)".
Volkerding said he had discovered how bad things were in 2017 when he managed to get some numbers out of the people running the store.
"I thought the sales were just that bad, and was really rather depressed about it. Another side note – the ownership of the 60% portion of the store changed hands behind my back. Nobody thought they needed to tell me about this. At that point I'd say things got considerably worse for me."
The commercialisation of Slackware was initially undertaken with Michael Johnston of Morse Telecommunications in 1994. After that, Volkerding moved to a venture with the founder of Walnut Creek CDROM, Robert Bruce.
Later, Volkerding teamed up with Bruce to set up a Slackware company.
iTWire has written to the Slackware store, seeking comment on Volkerding's claims.
Update, 27 July: Volkerding has posted a link to his PayPal site for donations.