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A BIOS is just code at the cold-boot memory location, there's no obvious reason to believe that isn't a simple extension to this project. Equally, the TRAP mech

A BIOS is just code at the cold-boot memory location, there's no obvious reason to believe that isn't a simple extension to this project. Equally, the TRAP mechanism for I/O to terminal is not vastly different to the INT 21h mechanism, obviously much less powerful, but pretty similar to the emulation you might want to do to run DOS programs. I don't think this is as far from a running model of an early 8- or 16-bit as you might be implying: of course emulating other hardware is more work, especially if you wanted eg graphical output or a network card or something, but the actual _interfacing_ with those components is not that difficult..

jfrunyon 5y ago
> A BIOS is just code at the cold-boot memory location No, the BIOS (or UEFI) does quite a bit of system setup and provides quite a bit of system services. It's much more than "just code"; "just code" can do anything, a BIOS has to do many very specific things. > Equally, the TRAP mechanism for I/O to terminal is not vastly different to the INT 21h mechanism And what does that have to do with anything? What software uses an interrupt to display things?! LOL INT 21h is for input, first off, nothing "to terminal". But second, that hasn't actually been usable in about 25+ years. > I don't think this is as far from a running model of an early 8- or 16-bit as you might be implying I don't think you understand just how complex computers have been for the past decades. The author's stated intention was to "better understand how computers work". This project did not teach him that; it taught him how CPUs work(ed). You can argue that it taught him how computers worked 3 decades ago all you want; that's not even slightly relevant.