Originally Posted by shattered
ec1842 WIP. This is almost a PC AT clone, sans second DMA chip and plus other funkiness (a modified 8086 clone plus an external MMU to support running software for 80286). Quite nice font, too:

[Linked Image from i.imgur.com]

Technical manual for this machine hasn't surfaced yet, but here are some notes from a training course for service techs -- https://www.gleb.cz/ES1841/ES1841-Lections-FromSerg.zip

They do explain how the MMU works (second PDF, pages 27-31). POST uses it to test memory outside 640K range. There's also simpler memory banking hardware, driven via port 0x73 (same PDF, page 36).

poisk2 is a XT clone with RTC (mc146818 clone), 640K or 2MB memory (with built-in EMS support). It's not as interesting as poisk1, but has a hardware workaround for bad memory chips -- address lines are routed via SRAM and POST uses this to exclude them from linear addressing. You could probably build a multitasking DOS around that smile