During 1993 and 1994 I wrote a book for Addison Wesley about how to create a professionnal video game on PCs.
At that time, you had to know a lot about the underlying hardware and to be fluent in assembly language and C or C++:
-- Recall yourself the Intel 386 and its 32-bit protected memory model for instance. In that mode, you were able to address all the memory at once, avoiding to dea with EMS.
-- And what about the various graphics card that were on the market at that time? Each chipset had to be adressed specifically with the relevant asm code and port management. And by 1993, no much -- not to say none -- information was available, including on the Internet.
-- The sound cards? Do you remember the Garavis Ultra Sound ?
-- And what to say of the interrupts for DOS.

And much more in the book.

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