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The main problem seems to be that the only way the BIOS can boot an OS is a mass storage device with executable code in the boot sector, in contrast to older co
by grishka 1y ago
The main problem seems to be that the only way the BIOS can boot an OS is a mass storage device with executable code in the boot sector, in contrast to older computers that had some sort of monitor/debugger in their ROM. I haven't researched disk drive interfaces, but trying to hook up a floppy drive to some toggle switches so I could write a boot disk would be my first step. But then modern motherboards don't have floppy drive controllers ¯\_(ツ)_/¯
Of course you can also try to reprogram the BIOS ROM on the motherboard, but you're likely to need a full OS to first reverse engineer it enough to know where to stick your debugger code.
- vdupras 1y agoI think the broad idea isn't to directly, for example, program a floppy disk drive (to boot a PC from BIOS) driver from such a front panel (a gargantuan task), but to gradually bootstrap your way up there. For example, you could build yourself a makeshift hex keyboard and load a driver for that keyboard onto an ATmega. Good! from that point on, you can enter bytes faster. Then, you hook a few seg7 together to have some kind of display. Even better! ... and so on, until you can drive that FDD.
- grishka 1y agoOr emulate one. Yeah, right.