DMA chaining is simply magic. First stumbled across it in a Microchip PIC. Does anyone know when it was invented? All I could find was this 2003 IBM patent http

DMA chaining is simply magic. First stumbled across it in a Microchip PIC. Does anyone know when it was invented? All I could find was this 2003 IBM patent https://patents.google.com/patent/US20030229733A1/en https://patents.google.com/patent/US20030229733A1/en but I have a feeling Microchip had it earlier?