No they didn't, read on Compaq clean room reverse engineering, the lawsuit, and IBM's failed attempt to regain the PC market with MCA and PS/2, after losing it.
"By June 1983 PC Magazine defined "PC 'clone'" as "a computer [that can] accommodate the user who takes a disk home from an IBM PC, walks across the room, and plugs it into the 'foreign' machine".[7] Demand for the PC by then was so strong that dealers received 60% or less of the inventory they wanted,[8] and many customers purchased clones instead.[9][10][11] Columbia Data Products produced the first computer more or less compatible with the IBM PC standard during June 1982, soon followed by Eagle Computer. Compaq announced its first product, an IBM PC compatible in November 1982, the Compaq Portable. The Compaq was the first sewing machine-sized portable computer that was essentially 100% PC-compatible. The court decision in Apple v. Franklin, was that BIOS code was protected by copyright law, but it could reverse-engineer the IBM BIOS and then write its own BIOS using clean room design. Note this was over a year after Compaq released the Portable. The money and research put into reverse-engineering the BIOS was a calculated risk. "
Copyright law and clean room design being the magic words.
Followed a couple of years later with,
"Compaq, IBM Reach Broad Patent-Sharing Agreement"
