After discussions with Microsoft, IBM decided to use 86-DOS (QDOS), a CP/M-like operating system that Microsoft bought from Seattle Computer Products renaming it MS-DOS. Microsoft adapted it for PC, and licensed it to IBM. It was sold by IBM under the name of PC DOS. After learning about the deal, Digital Research founder Gary Kildall threatened to sue IBM for infringing DRI's intellectual property, and IBM agreed to offer CP/M-86 as an alternative operating system on the PC to settle the claim. Most of the BIOS drivers for CP/M-86 for the IBM PC were written by Andy Johnson-Laird.