Hi everyone,

I've just found something interesting when browsing Wikipedia.

"EC-1842

16-bit PC with RAM up to 2 MB on the K1810VM86M processor with a clock frequency of 10 MHz; two floppy disk drives with a capacity of 720 KB; NMD type "hard drive" for 20 MB, the exchange rate is 5 Mbit / s. The display is black and white or color, EGA, 16 and 64 gradations of brightness or color, text mode - 25 or 43 lines of 80 characters, graphics modes up to 640 × 350 pixels. Universal keyboard, 110 keys, including 12 function keys. Mouse type manipulator. Interfaces: parallel (IRPR-M), serial (C2), LAN interface "Relay". Since the industry of the USSR did not master the production of the i80286 analogue, a special LSI of the KA1843VG1 virtual memory manager was developed for this computer, which, working in conjunction with the K1810VM86M microprocessor, provided it with the ability to work in a protected mode and execute software designed for the i80286, albeit with slightly slower performance. The EU-1842 can be considered the most productive Soviet personal computer, made entirely on the domestic element base.

Local network "Relay" - ring, up to 125 computers, the distance between machines is not more than 1500 m, the data transfer rate is 200-500 Kbps.

Also produced was the EC-1855 , a modification of the EC-1842 for special applications."

Source: Ru. Wikipedia
Translation via Google Translator

I think that's quite interesting! 😃

While I heard that East Germany had developed an 80286 clone in the late 80s, the U80601 , I've never heard about a hot-rod 8086 with an MMU that's 80286 compatible.

Makes me wonder if that thing could run MS-DOS 6.2x with Himem.sys, as well as Windows 3.0.

Edit: Maybe rather not.

"[..] Practically, the EU-1842 could address up to 4MB.
At one time there was an idea to check whether Windows 3.1 would work on EU-1842,
but after studying the notes from serg and parsing the emulator, I understand
that idea is crazy. " (page 14)

Source: https://www.phantom.sannata.org/viewtopic.php?f=12&t=15452

Edit: As far as I understand, the 286 emulation concept involved a special version of the 8086 (w/ PUSHA instruction), the VM86M, that aforementioned special MMU and a software emulator.
The MMU was needed to detect invalid opcodes, among other things.

A few pages later, these dudes managed to get a DOS game executable running which they had previously compiled with 286 instructions.
Game with source code: https://www.classicdosgames.com/game/Catacomb.html

Still, that's very interesting to read.

Edit: This kind of reminds me of EMU386, which emulates 80386 Real-Mode instructions in software on an 80286 CPU.
With the difference that the 80286 already has an MMU and can "handle" invalid opcodes without extra hardware. That's why 8087 emulator TSRs are possible there.
The 80186 might be sufficiently advanced, too, but I'm not 100% sure, since I can't double check.