This was also true for all x86 ancestor hardware. For example, the IBM XT came with a technical reference manual that provided the schematics and source code (

This was also true for all x86 ancestor hardware. For example, the IBM XT came with a technical reference manual that provided the schematics and source code (https://archive.org/details/bitsavers_ibmpcxt150ferenceApr83_26321497 https://archive.org/details/bitsavers_ibmpcxt150ferenceApr83...). In fact, the fundamental success of the PC/XT line was that it had increased user-expandability and maintainability over the competitors, as documented extensively in all accounts of the period. And we're all typing on crazy descendants of the Apple II architecture, because pieces of it informed all subsequent architectures: "It was also decided along the way that the machine would have an "open" architecture, like that of the Apple family. IBM would include slots under the cover of the machine that could accommodate plug-in boards that would add features or even change the entire personality of the PC. And, to make it relatively easy for outside companies to participate in the building of the PC market, IBM would publish a Technical Reference Manual with the entire set of electrical schematics for the machine and a full explanation and printout of the ROM-based BIOS (Basic input Output System) that provides the hooks into the machine for hardware and software. The ROM BIOS and the IBM logo were actually the only elements of the entire machine that bore an IBM copyright." (http://www.atarimagazines.com/creative/v10n11/298_IBM_colossus_of_Armonk.php http://www.atarimagazines.com/creative/v10n11/298_IBM_coloss...) Frankly, your lack of understanding of the history you're so confidently asserting facts about is beyond shocking. I'm sorry if that seems mean-spirited, but there's no other way to put it.