xqemu VS RPI-Engine

These projects are called compatibility layers, or "translation layers" sometimes. I think XQEmu (OG XBox on PC) works the same.

Yes:

https://xemu.app/

https://xqemu.com/

Are both original Xbox emulators built off of QEMU. I've only used Xemu, but performance was pretty good for the games I tried on it (it doesn't have a way to upscale rendering yet though).

It's indeed a bit like a kexec.

On system initialization, kernel routines are copied into RAM by the bootloader[1]. Executables run in ring 0, and have a jump table to call kernel routines in their own address space (IIRC) [2].

As such, loading any executable counts as a soft reboot.

Also, there is a functioning open source emulator, Xqemu [3] (and its sibling/fork focused on speed and compatibility more than accuracy, xemu [4])

I recommend reading "17 mistakes Microsoft made in the Xbox security system", which is very informative [5].

[1]: https://xboxdevwiki.net/Boot_Process

[2]: https://xboxdevwiki.net/Kernel

[3]: https://xqemu.com/

[4]: https://xemu.app/

[5]: https://xboxdevwiki.net/17_Mistakes_Microsoft_Made_in_the_Xb...

There is one emulator currently that does do that, the "XQEMU" emulator for the original Xbox https://xqemu.com/

It's in its infant stages at the moment according to the "Emulation General" wiki and focuses heavily on "accuracy" over performance

Other emulators such as CXBX-Reloaded have made larger strides, currently emulating roughly 10% of the software library

It's also worth stating, while the Xbox seems like an "easy" target, being based on an ia-32 (Pentium III) PC with an Nvidia GeForce chip (somewhere between a Geforce 2 and 3 at the time) it is an absolutely monstrous beast with minimal documentation about its hardware and numerous "gotchas"

It also has a very small library of 'exclusive' content which detracts from gaining many developers

I would strongly strongly suggest investigating MUDs if that's your bag. They're non-graphical so they can be built and maintained by small numbers of people with low programming skills and they tend to be almost entirely about community experiences. I'll just leave http://www.middle-earth.us/ here because it's where I met my now SO and it's an absolutely wonderful community - but there are hundreds of them out there. They do take a serious time commitment though, since they're all about building up that interesting social world.

MUDs are a class of game that is terribly underrated. I've played on a few different one (mostly toward the RP focused end of things) but I think the whole family of games shows just how effective imagination can be when coupled solely with text descriptions.

I have extremely strong memories from Shadows of Isildur[1] and met my spouse there!

1. http://www.middle-earth.us/

A MUD I worked (uh volunteered, as a total newbie) on had a soft-reboot implementation for deploys that blew my mind when I first saw it in action. Open telnet connections were all sent keep alives before the MUD launched a new instance of itself from the executable (which may have been a different version from the currently running copy) and then killed itself. To users on the other end a message appeared saying "Relaunching the server" and was followed up shortly by "You may now resume play". Since this engine was designed to constantly fall over due to instabilities and OOMs it stored the current game state in a persistent state (originally on-disk files - most of it was migrated to MySQL) so the only things that really needed hacking were re-acquiring the right sockets and remembering which user is which.

This included, FYI, under development new game elements which were mostly written and launched using a mix of things called RPROGs, OPROGs, CPROGs and Descs (among other things) all of which were written in a custom domain language input into the MUD itself - devs like myself worked only on underlying mechanics and had no need to wander into the specifics of all those triggers.

This probably opened up a number of security holes but, given that the game only ever checked the first six characters of a password (and checked them one by one against a plaintext copy) there were lower fruit available to criticize.

If you want to check it out an older copy is available open-sourced[1] - it's a DIKU variant MUD.

1. https://github.com/webbj74/RPI-Engine