MINTIA (not vibecoded) | Operating System Development | Page 30

warm pine May 16, 2026, 12:12 AM

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we know that even VMS already was laced with Unixisms

cursive charm May 16, 2026, 12:12 AM

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don't tell them they had a mach guy on the NT team

warm pine May 16, 2026, 12:13 AM

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in general in operating systems now to talk about "not unix-like systems" is like talking about "no newton physics"

twilit smelt May 16, 2026, 12:14 AM

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warm pine we know that even VMS already was laced with Unixisms

and, less appreciated but just as true, unix is laced with VMS-isms

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the academic discourse in the 80s was constantly comparing the two in deep technical terms and the feature exchange went both ways in ways that are not often appreciated now

warm pine May 16, 2026, 12:14 AM

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there is probably some out there but he so influenced the field that almost anything today is constituted out of his blood and organs

warm pine May 16, 2026, 12:15 AM

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twilit smelt and, less appreciated but just as true, unix is laced with VMS-isms

some day i would like to enumerate some of these influences and write a little about it

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and when we go to their common ancestor in MULTICS there is even more to say

cursive charm May 16, 2026, 12:16 AM

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apparently, that "vibe" quote i posted had the handle lookup bullet point right beside it:

This centralization of system components in the kernel has proven to be harmful due to the dispatcher lock before Windows 7 and apparently handle lookup cost

twilit smelt May 16, 2026, 12:17 AM

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cursive charm apparently, that "vibe" quote i posted had the handle lookup bullet point right ...

its funny because NT had significantly finer grained locks than most contemporary unixes

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of which many were dealing with BKLs

cursive charm May 16, 2026, 12:17 AM

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also, in the following section:

On the designers behind Micah (not to be confused with DEC Mica, another operating system Dave Cutler led the development of), Microsoft's codename for the OS/2 personality of Windows NT: "A lot of people that were on the design team had almost zero experience with actually building an operating system" ― Dave Cutler

twilit smelt May 16, 2026, 12:17 AM

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wtf

cursive charm May 16, 2026, 12:17 AM

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their quote of dave actually refers to DEC MICA, btw

twilit smelt May 16, 2026, 12:17 AM

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nonsense lol

warm pine May 16, 2026, 12:17 AM

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cursive charm apparently, that "vibe" quote i posted had the handle lookup bullet point right ...

the dispatcher lock was really just a big scheduling lock which disappeared frankly right in time

cursive charm May 16, 2026, 12:18 AM

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twilit smelt wtf

literally my first reaction, lol

twilit smelt May 16, 2026, 12:18 AM

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also it had been dramatically shrunk around the year 2000 already

warm pine May 16, 2026, 12:18 AM

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2009 was right around the time all the open source operating systems were vying to get rid of big locks

twilit smelt May 16, 2026, 12:18 AM

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when the dispatcher lock was removed it mostly covered like blocking and object waits and object signaling

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scheduling had been reduced to per-cpu queues around win2k already

twilit smelt May 16, 2026, 12:19 AM

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cursive charm their quote of dave actually refers to DEC MICA, btw

how did that goober get the impression that theres some other "micah" thing that refers to the os/2 subsystem

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its funny how this is a parallel to ozix being described as "mica's ultrix subsystem" in various places

cursive charm May 16, 2026, 12:19 AM

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I DON'T KNOW, LOL

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i was genuinely confused when i first read it

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i watched the interview several times, and cutler never refers to some OS/2 subsystem codenamed "micah"

twilit smelt May 16, 2026, 12:20 AM

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micah sitting at the table with mica, nt, vms, and ozix

would-this-now-be-a-good-time-to-add-graggle-simpson-into-v0-03mwzmlsisyf1.png

cursive charm May 16, 2026, 12:21 AM

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i honestly think they must've took dave's pronunciation of "MICA" as if he was talking about something else

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i'm bad at spelling, jfc, lol

cursive charm May 16, 2026, 12:21 AM

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twilit smelt micah sitting at the table with mica, nt, vms, and ozix

LMAO

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i almost wanna file an issue regarding this, but they've yet to respond to the one issue i've already opened

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it's about how they said somewhere that "MS split the BASE.DLL into KERNEL32.DLL and NTDLL.DLL upon release" or whatever

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which

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no

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i really don't know how they think that when:

twilit smelt May 16, 2026, 12:25 AM

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that would be impressive considering ntdll.dll existed in mica

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and not only there but in VMS too

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it was called mica$fm_share and starlet.olb respectively (starlet being VMS's codename, and the meaning of fm_share is unknown even to dave cutler who said he forgot when asked)

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ntdll's original name in the NT workbook was udll.dll and it was spec'd in like 1989

cursive charm May 16, 2026, 12:27 AM

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you might also notice there's a LDRDLL.DLL, which was apparently for the OS/2 subsystem, from what i can tell

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i had to make a note on my issue report so they don't end up getting any wrong ideas: https://github.com/ElliotKillick/operating-system-design-review/issues/2#issuecomment-3693743978

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really, the "split" thing was kinda backwards from what they actually did anyway

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the base and console win32 APIs were merged into KERNEL32.DLL, iirc

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and NTDLL.DLL doesn't consist of "public" or "private Windows APIs," unless they were referring to NT APIs, i guess

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so it has nothing to do with win32 anyway other than that they were implemented on top of the NT APIs

twilit smelt May 16, 2026, 12:34 AM

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this guy is such a fucking hack

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The deadly NtTerminateProcess was first added beginning in Windows NT 3.1 seemingly as an incredibly poor and hasty but deliberate hack posing as a valid design choice.

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how is that different from sigkill

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jfc

cursive charm May 16, 2026, 12:36 AM

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they might've meant NtTerminateThread() somehow?

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the main document has a huge rant about its win32 equivalent, TerminateThread()

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oh, god, i remember now

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this guy hates how NtTerminateProcess(NULL, Status) terminates every other thread in the calling process

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that's the "deliberate hack posing as a valid design choice," apparently

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because the very first thing RtlExitUserProcess() does is do that

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what if you pass the flag and the inner implementation just gets the heap from the PEB anyway???

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smss.exe typically has only one DLL loaded (i.e., ntdll.dll), btw

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it doesn't rely on much

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yet it's there along with four other processes which apparently have "plethora of highly interconnected DLLs" loaded

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here's my favorite part:

Microsoft's reasoning behind the return type of LoadLibrary stems from the 16-bit Windows API (going back to Windows 1.0 when the function was introduced), where libraries became conflated with data files or memory-mapped files meaning "libraries" could exist for the sole purpose of containing data with no code. In the first release of Windows NT (i.e. Windows NT 3.1), Microsoft carried forward this unique mistake while also adding an extension for specifying that a "library" must load only as a memory-mapped file and how to open this file.
https://github.com/ElliotKillick/operating-system-design-review/blob/4459d385d6de333fce3f7b617708a3849f3e908f/README.md#loadlibrary-vs-dlopen-return-type

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here's the part of ruediger asche's article that claim was based on:

A virtual address in the address space of a process.

The concept that makes this implementation possible is the memory-mapped file (or section object). Whereas Windows 3.1 needs to copy data from an executable file into main memory to build code segments or load resources, Windows NT only needs to create a memory-mapped file object that is backed by the executable file instead of the system pagefile.

twilit smelt May 16, 2026, 12:58 AM

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does he not understand how demand paging an executable works

cursive charm May 16, 2026, 12:58 AM

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no

twilit smelt May 16, 2026, 12:58 AM

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and hes writing an "os design review" github page

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with 350+ stars

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nice

cursive charm May 16, 2026, 12:59 AM

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i think he just read up to "load resources" and his brain immediately shut down

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plus, none of this has to do with why LoadLibrary() returns a pointer to the module's image in memory instead of its data table entry anyway

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after all, it returns an HMODULE, an opaque type, not a PIMAGE_DOS_HEADER

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i'm guessing they were conflating all this stuff with LoadLibraryEx()'s LOAD_LIBRARY_AS_DATAFILE flag because they directly link to raymond's blog which talks about it

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for the record, technically, in win3.x, LoadLibrary() returned an HINSTANCE

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Given any amount of forethought, it is reasonable to expect that Windows' focus on dynamic loading of executable modules—unlike the prevalent static linking of the time—would have ensured a solid design for its core library loading API. Especially since Multics had already pioneered the idea of dynamic linking, used memory-mapped files to share data, and supported dynamic loading years before Microsoft was even founded.
🙃

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Indeed, the module handle implementation quirk in the library loader exemplifies an avoidable misstep—one that, like most Windows API oversights, exists as an outcome of Microsoft's expedient development style when creating their core technologies.
oh my god, they spent the first few years of development writing a design workbook

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"expedient" is not the word one should use to describe NT's initial development

twilit smelt May 16, 2026, 1:13 AM

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technically they spent the first like 5 years of development writing a design handbook if you count the entirety of mica as a design exercise for NT

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btw have you seen mica's complete original design handbook

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its much more thorough than NT's

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probably because by NT time period they didnt want to rewrite all at

cursive charm May 16, 2026, 1:14 AM

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i think i've seen it

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i've saw it shared either in disncord or betawiki

twilit smelt May 16, 2026, 1:15 AM

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https://www.computerhistory.org/collections/catalog/102750714

Mica operating system - 102750714 - CHM

These folders contain naming conventions, development plans, and working design documents for Mica, including an early draft where Mica is called P.TBD. Mica was a PRISM operating system.

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asset 3 is a late stage "chapter overviews" book

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asset 4 is the complete design book from 1986

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when it was called P.VMS

cursive charm May 16, 2026, 1:16 AM

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apparently, safari on iOS did not like that page

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Macintosh: First appeared in System 7 (1991) using the Motorola 68k architecture (Apple only shipped Macintosh with their own hardware and not move to Intel 386 until 2006). While Macintosh is a Unix-like OS, Apple developed their own proprietary GUI solution for their operating system.
what

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did they skip a bajillion sources regarding apple's OS history

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system 7 wasn't the first version, and OS X is being conflated with… classic macintosh?

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There were many operating systems written for the Virtual Address eXtension (VAX) instruction set architecture (ISA). These include the original OpenVMS OS (1977) which was not Unix-like and later some Unix-like OSs. VAX was ahead of its time, featuring full 32-bit protected mode support. However, factors such as being closely tied to the non-portable OpenVMS OS, strategic missteps of Digital Equipment Corporation (DEC) like being late to microcomputers with the MicroVAX I releasing in late 1984, the high expense of VAX systems, and competition from other architectures ultimately led to VAX not catching on.
it was originally just called VMS

twilit smelt May 16, 2026, 1:23 AM

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where is that from

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VAX not catching on

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bruh

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it caught on

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big time

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MAJOR cash cow

cursive charm May 16, 2026, 1:24 AM

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https://github.com/ElliotKillick/operating-system-design-review/blob/4459d385d6de333fce3f7b617708a3849f3e908f/data/operating-systems-development-history.md#virtual-address-spaces

twilit smelt May 16, 2026, 1:24 AM

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christ

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this guy sucks

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i hate it when fucking idiots have no idea what theyre talking about and besmirch some cool topic by insisting upon commenting on it even though they dont actually respect it enough to get it right

cursive charm May 16, 2026, 1:25 AM

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they're a security researcher, apparently

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evidently, they don't understand even the OSes they like enough for that to matter

twilit smelt May 16, 2026, 1:26 AM

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im sure theyre okay at their job

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but theyre no historian

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thats for sure

cursive charm May 16, 2026, 1:26 AM

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this one is probably the worst i've read by far: https://github.com/ElliotKillick/operating-system-design-review/blob/4459d385d6de333fce3f7b617708a3849f3e908f/data/windows/the-rise-of-microsoft.md

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wait, did they move some stuff around

short owl May 16, 2026, 1:28 AM

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Larpliot Killarp

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What a bunch of bs

cursive charm May 16, 2026, 1:34 AM

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oh my god, so here's the part that was removed in later revisions: https://github.com/ElliotKillick/operating-system-design-review/blob/c3193467616797ead839cb34e2f43d68473639d2/README.md#an-alternate-reality

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and here's a fragment of that part:

This strategy would have been highly feasible seeing as Apple followed a similar timeline starting with Apple DOS, switching to A/UX (based on AT&T Unix), and later switched again to create MacOS based on NeXTSTEP (they purchased this system by acquiring NeXT), which was itself was based on the permissively licesned 4.3BSD Unix.

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APPLE DOS??????

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why did we skip over the classic mac??????

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also, A/UX was a product separate from the classic mac OS that ultimately didn't go anywhere

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i'm not really sure why it was brought up as if they made it the basis for their flagship OS

twilit smelt May 16, 2026, 2:18 AM

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should i call the linux subsystem "mintix"

cursive charm May 16, 2026, 2:28 AM

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mintia subsystem for linux

warm mural May 16, 2026, 3:15 AM

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twilit smelt should i call the linux subsystem "mintix"

minux

twilit smelt May 16, 2026, 3:27 AM

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warm mural minux

sounds too much like minix

warm mural May 16, 2026, 3:28 AM

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Both are one letter away

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meme

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Mintix is better though

shadow ridge May 16, 2026, 6:30 AM

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twilit smelt should i call the linux subsystem "mintix"

limnux

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if you didnt do the renaming this would make so much sense

shadow ridge May 16, 2026, 7:00 AM

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The large quantity of memory mapped regions in the form of libraries can decrease memory efficiency thus leading to higher turnover in the memory pager and an increased page fault rate. Page faults force the operating system to swap memory from disk I/O thus resulting in excessive storage reads and writes, slowing down performance.

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this guy doesnt know that cache exists

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actually i feel like he thinks that literally every single page fault will cause disk io

raven drift May 16, 2026, 7:40 AM

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I tried to make the handle table lock free in Managarm but it was a perf regression due to too many objects getting queued for RCU cleanup

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Our RCU implementation (particularly the cleanup queue) is not perfect so some perf can probably still be gained but I'd expect it to only be faster in scenarios with a lot of parallelism

twilit smelt May 16, 2026, 7:43 AM

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shadow ridge if you didnt do the renaming this would make so much sense

some day you will forget about the renaming of limnstation to xrstatino like the rest of the world

twilit smelt May 16, 2026, 7:45 AM

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raven drift I tried to make the handle table lock free in Managarm but it was a perf regress...

the fact NT has done well enough with just a per-process handle table pushlock up til now has motivated me to probably just do the same

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prob is for the best to unlock that lock as much as possible though

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for example, if it is a multi level table and a table segment needs to be allocated, the lock should probably be unlocked across the allocation and then retaken and then check to see if that segment still needs to be added to the radix tree

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so its only held very briefly across lookups

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and never while calling into another subsystem

shadow ridge May 16, 2026, 7:57 AM

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twilit smelt some day you will forget about the renaming of limnstation to xrstatino like the...

1/5 never forget

twilit smelt May 16, 2026, 7:58 AM

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i have not been entirely happy with the choice of "xr" but i havent come up with anything better either

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limnstation def had to go that was a dumb name

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or at least it was a fine name for a project of a different vibe

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it was fine when the aesthetic was like quirky sparcstation/sgi type thing and not the COLD HARD STEEL and RIGOROUS ARCHITECTURE of like a DEC box

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which is more what it is now

shadow ridge May 16, 2026, 8:01 AM

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well you are correct

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XRstation has a more corporate / professional tone to it

twilit smelt May 16, 2026, 8:06 AM

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68747470733a2f2f692e696d6775722e636f6d2f524746524748682e706e67.png

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^limnstation vibe

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^xrstation vibe

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they r different.

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unfortunately for old limnstation's vibe, DEC happens to have like 10k+ pages of internal corporate correspondence and documents publicly available today

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it was inevitable that it would win all of my mindshare

digital pivot May 16, 2026, 8:09 AM

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twilit smelt the fact NT has done well enough with just a per-process handle table pushlock u...

on windows its one lock?

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per process for the entire table

twilit smelt May 16, 2026, 8:09 AM

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well i was simplifying a bit

digital pivot May 16, 2026, 8:09 AM

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or for each entry

twilit smelt May 16, 2026, 8:10 AM

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the structure seems to have multiple pushlocks but for the handle table structure there seems to be like 1 lock

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presumably taken shared during lookups

hollow musk May 16, 2026, 8:49 AM

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it turns out that the lookup functions don't take per-table this lock

twilit smelt May 16, 2026, 9:07 AM

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hollow musk it turns out that the lookup functions don't take per-table this lock

how do they worm

hollow musk May 16, 2026, 9:23 AM

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I don't know

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but I can see that handle lookup in the table is lock free up to the point of obtaining the entry, the entry itself has an embedded exclusive bit lock

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if the bit is already clear the thread waits through the handle table's HandleContentionEvent

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for HandleContentionEvent it uses some kind of futex-like pushlock that I'm not familiar with

twilit smelt May 16, 2026, 9:46 AM

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hollow musk but I can see that handle lookup in the table is lock free up to the point of ob...

it cant be COMPLETELY lock free with no synchronization at all

digital pivot May 16, 2026, 10:09 AM

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how does it obtain an entry from the table

warm mural May 16, 2026, 10:56 AM

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raven drift I tried to make the handle table lock free in Managarm but it was a perf regress...

This might be a place where epoch based mechanisms like in freebsd shine, in particular they can avoid having a huge chain of pending callbacks

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Which has been shown to be more memory efficient and faster in some cases

digital pivot May 16, 2026, 11:37 AM

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digital pivot how does it obtain an entry from the table

should install ghidra and check how its done

mortal thunder May 16, 2026, 4:54 PM

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this feels like it pollutes the kernel with a posixism/unixism for no particular reason. i would add a fd to handle table personally

short owl May 16, 2026, 4:57 PM

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Wdym no particular reason

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They just said it is for the Linux subsystem

mortal thunder May 16, 2026, 4:59 PM

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thats not a particular reason

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also what if you wanna have a handle to a timer for example

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as part of an implementation of a linuxoid object like timerfd

digital pivot May 16, 2026, 5:30 PM

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digital pivot should install ghidra and check how its done

the one that seems most appropriate based on the name is ExpLookupHandleTableEntry

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i can confirm it doesnt take the HandleTableLock

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longlong ExpLookupHandleTableEntry(uint *param_1,ulonglong param_2)

{
    ulonglong uVar1;
    ulonglong uVar2;
    
    uVar2 = param_2 & 0xfffffffffffffffc;
    if (*param_1 <= uVar2) {
        return 0;
    }
    uVar1 = *(ulonglong *)(param_1 + 2);
    if (((uint)uVar1 & 3) == 1) {
        return *(longlong *)((uVar1 - 1) + (param_2 >> 10) * 8) +
               (ulonglong)((uint)uVar2 & 0x3ff) * 4;
    }
    if ((uVar1 & 3) == 0) {
        return uVar1 + uVar2 * 4;
    }
    return *(longlong *)
            (*(longlong *)((uVar1 - 2) + (param_2 >> 0x13) * 8) +
            (ulonglong)((uint)(param_2 >> 10) & 0x1ff) * 8) + (ulonglong)((uint)uVar2 & 0x3ff) * 4;
}

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though its not as if i understood it

twilit smelt May 16, 2026, 5:43 PM

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mortal thunder also what if you wanna have a handle to a timer for example

how does this impede that

craggy spire May 16, 2026, 5:52 PM

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twilit smelt presumably taken shared during lookups

That push lock is used for table expansion in exclusive mode

twilit smelt May 16, 2026, 6:01 PM

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craggy spire That push lock is used for table expansion in exclusive mode

is the handle table just never shrunk

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if you never garbage collect segments of the handle radix tree and only destroy it when the process goes away, then i can see how you could look it up locklessly and only take a lock when expanding (and do all this w/o RCU or equivalent)

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sounds dangerous though

craggy spire May 16, 2026, 6:06 PM

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twilit smelt is the handle table just never shrunk

IIRC yes

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Handle table levels are allocated on demand, then linked into the table, and then retained until the whole handle table is destroyed

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Closing handles only returns entries to one of the free lists

twilit smelt May 16, 2026, 6:12 PM

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i mean

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its fine if theres a reasonable handle limit i guess

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especially since the handle table is in paged pool

digital pivot May 16, 2026, 6:42 PM

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whats the limit btw?

twilit smelt May 16, 2026, 6:45 PM

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thats my point the limit isnt really reasonable

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its like 16 million

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so a process could waste like 128 MB

warm mural May 16, 2026, 6:49 PM

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if it's paged 🤷‍♂️

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also like

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memory sizes are huge nowadays

twilit smelt May 16, 2026, 7:07 PM

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also handle table space is charged to process quota

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https://old.reddit.com/r/osdev/comments/1td1qjd/my_microkernel_single_address_space_operating/

r/osdev

My Microkernel Single Address Space Operating System is working (so...

i've been working on this little project for awhile... it’s called SexOS / Sex, and it started as an old microkernel idea I…

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single address space microkernel

warm mural May 16, 2026, 7:12 PM

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SaaS-OS experiment

twilit smelt May 16, 2026, 7:12 PM

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pronouncing itanium as if it were a latin word just to feel alive

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ee tah nee oom

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ITANIVM

warm mural May 16, 2026, 7:12 PM

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twilit smelt https://old.reddit.com/r/osdev/comments/1td1qjd/my_microkernel_single_address_sp...

he stole your idea

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of protection keys

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you're just jealous

twilit smelt May 16, 2026, 7:13 PM

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i think this post was written using an LLM to generate a draft and then they like rewrote it in their own voice

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but the LLM style prose remains

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its funny how thats a thing people do sometimes and it remains kind of obvious that they did that

warm mural May 16, 2026, 7:13 PM

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warm mural of protection keys

unironically i think that is a really cool research space tho

twilit smelt May 16, 2026, 7:13 PM

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What I mean by restricted AI workflow: I’m using Codex/Claude/DeepSeek as bounded agents that get tiny missions like “prove keyboard window controls” or “fix topbar restore regression,” then build, boot, grep serial logs, and stop if the change would cross kernel/ABI boundaries. So, not vibe coded, but definitely a major help speeding up proofing and debugging. What I've found most useful is feeding my logs into NotebookLM and making little podcasts about the project along the

warm mural May 16, 2026, 7:13 PM

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maybe in the future we'll have microkernels-ish all in ring 0

warm pine May 16, 2026, 7:17 PM

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precisely what is a PDX message layer

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object/graph-style file organization
you also have to ask exactly what is meant by "graph-style file organisation"

teal trench May 16, 2026, 7:18 PM

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the sex microkernel

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the author starred managarm today

warm pine May 16, 2026, 7:18 PM

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can you imagine two files that are cyclical? far be from me such a thought

teal trench May 16, 2026, 7:19 PM

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well a tree is a graph meme

warm pine May 16, 2026, 7:20 PM

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teal trench well a tree *is* a graph <:meme:575445094589661215>

we are missing a trick

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how much cooler might things sound if we name them by superordinate terms?

teal trench May 16, 2026, 7:20 PM

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twilit smelt > What I mean by restricted AI workflow: I’m using Codex/Claude/DeepSeek as boun...

the youtube channel doesn't inspire confidence

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i clicked on one, and it's narrated by an ai voice too

warm pine May 16, 2026, 7:21 PM

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teal trench the youtube channel doesn't inspire confidence

let's hope the hypnotist isn't zack polanski or else we will soon be seeing the worst rule 34 ever heard of

teal trench May 16, 2026, 7:22 PM

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lmao

twilit smelt May 16, 2026, 7:25 PM

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https://www.youtube.com/watch?v=_UXrCq384hE

YouTube

c8udyp

Boards of Canada - Korona

Korona by Boards of Canada from the Mask100 Sampler. Video is an excerpt from the film "Decasia" by Bill Morrison.

▶ Play video

warm mural May 16, 2026, 7:25 PM

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managarm mention

teal trench May 16, 2026, 7:26 PM

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https://youtu.be/o_WWLcEXY4o?t=158 it's just notebook lm meanderings with ai generated visuals, like here it goes "address device command using type 8, actually, scratch that, type 8 on the transfer ring is a transfer no-op, [...], the command ring requires type 11 for the address device command"

warm mural May 16, 2026, 7:28 PM

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warm mural managarm mention

hey does anyone know why korona is named korona

digital pivot May 16, 2026, 7:30 PM

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twilit smelt so a process could waste like 128 MB

but thats a bit unrealistic because typically one doesnt exceed a few hundred thousand handles globally on the system

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probably most processes have only 1st level of allocation

craggy spire May 16, 2026, 7:31 PM

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twilit smelt so a process could waste like 128 MB

More like 256

twilit smelt May 16, 2026, 8:39 PM

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the weird pseudo- discord-train-of-thought prose thats popular in like SF tech culture will never stop enraging me

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JUST WRITE NORMALLY

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STOP DOING THIS

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its like the 500th abstracted layer of larp

teal trench May 16, 2026, 8:41 PM

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advanced larpatronics

twilit smelt May 16, 2026, 8:41 PM

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theyre imitating the form of a series of messages sent on an IM platform to seem more casual or more cracked or more authentic or something

#

its weird

#

its so so weird and theyve all been doing this for years

#

its like a bunch of robots

#

all falling in line

teal trench May 16, 2026, 8:42 PM

#

i love how the example code here also is just broken

#

spawning a thread and passing a pointer to a local that soon goes out of scope

twilit smelt May 16, 2026, 8:43 PM

#

yeah that too

#

christ

safe hollow May 16, 2026, 8:44 PM

#

literally nothing in the post is even correct

digital pivot May 16, 2026, 8:48 PM

#

twilit smelt JUST WRITE NORMALLY

imo this writing only works if you were an eyewitness and are recalling events rather than just retelling

twilit smelt May 16, 2026, 8:49 PM

#

if i were a larpmaxxer id have written the entire xr17032 architecture manual like that

#

when the processor is reset

the rs control register is set to zero

forcing it to kernel mode

#

imagine that for like 200 pages

#

thats how infuriating this style of non-instant-messaging posting is to me

#

#

writing an allocator is a standard project during a cs major here

#

it has to be a decent one too like it has to pass their benchmarks for fragmentation and performance

#

cant just do a k&r free list allocator or not merge blocks

#

that does not pass the benchmarks

#

why are people always acting like theres a large class of people who both write C and also think malloc() is black magic and have no idea how it could possibly work

#

im sure such people exist but i dont think its very many

warm pine May 16, 2026, 8:54 PM

#

twilit smelt the weird pseudo- discord-train-of-thought prose thats popular in like SF tech c...

confucius say

#

1 select

#

10,000 problem

mortal thunder May 16, 2026, 8:56 PM

#

twilit smelt how does this impede that

not sure what to reply to this but anyways

#

another idea could be that you just implement the linux fd table in the linux subsystem driver or whatever you use

#

if you plan on implementing it in kernel space

#

as opposed to a process' normal handle table

earnest zenith May 16, 2026, 10:42 PM

#

twilit smelt

Someone just posted this in #resources.

earnest zenith May 16, 2026, 10:42 PM

#

twilit smelt im sure such people exist but i dont think its very many

You'd be surprised.

warm mural May 16, 2026, 10:43 PM

#

Why are you talking like roboner.

twilit smelt May 16, 2026, 10:44 PM

#

lukflug is 5 punctuation marks and a sprinkle of annoyingness away from roboner at all times

short owl May 16, 2026, 11:11 PM

#

😭

earnest zenith May 16, 2026, 11:17 PM

#

warm mural Why are you talking like roboner.

wdym? 😭

earnest zenith May 16, 2026, 11:17 PM

#

twilit smelt lukflug is 5 punctuation marks and a sprinkle of annoyingness away from roboner ...

~~wow, I didn't know I was that annoying~~

short owl May 16, 2026, 11:20 PM

#

earnest zenith wdym? 😭

They're referring to yeint

earnest zenith May 16, 2026, 11:20 PM

#

ik

twilit smelt May 16, 2026, 11:21 PM

#

top 5 osdev discord moment

short owl May 16, 2026, 11:28 PM

#

A discord theme so bad it is a crime

twilit smelt May 16, 2026, 11:39 PM

#

i use it as an annoying people detector

#

#

owned!

cursive charm May 16, 2026, 11:54 PM

#

Stop using light mode || ||

carmine grove May 17, 2026, 5:55 AM

#

twilit smelt top 5 osdev discord moment

cyborg boner

short owl May 17, 2026, 7:07 AM

#

twilit smelt i use it as an annoying people detector

Curious, i thought using light mode was what annoying people did!

twilit smelt May 17, 2026, 7:57 AM

#

im annoying and proud

shadow ridge May 17, 2026, 9:09 AM

#

twilit smelt

i hate this tbh

#

LOLZ HES USING LIGHTMODE HAHAHAHAHAHAHAHAHAHA IS HE STUPID

#

like

#

shut the fuck up john funny

short owl May 17, 2026, 6:39 PM

#

Discord's light mode genuinely blinds me and is unbearable for my eyes

#

I can cope with light mode of other apps but not Discord's

twilit smelt May 17, 2026, 6:39 PM

#

short owl Discord's light mode genuinely blinds me and is unbearable for my eyes

there are like 20 different light modes

#

and im not using the 0xFFFFFF one

icy bridge May 17, 2026, 6:42 PM

#

#

need to add actual machine types because right now it doesn't have any firmware rom (which can't be added from cmdline like cpus can) but in theory the cpu side of things should work

short owl May 17, 2026, 6:43 PM

#

twilit smelt there are like 20 different light modes

Weird, i just see 3 free themes + the "change according to system" one

#

All the other ones are paywalled

twilit smelt May 17, 2026, 6:44 PM

#

icy bridge

oh wow are you going to add all my fake devices also

icy bridge May 17, 2026, 6:44 PM

#

probably

short owl May 17, 2026, 6:44 PM

#

icy bridge

Nice

icy bridge May 17, 2026, 6:44 PM

#

this is mostly meant to be a more debuggable alternative to xremu

short owl May 17, 2026, 6:44 PM

#

Does it have tcg accel?

icy bridge May 17, 2026, 6:44 PM

#

like xremu emulates caches and everything but this has actual gdbstub and watchpoints and everything

icy bridge May 17, 2026, 6:44 PM

#

short owl Does it have tcg accel?

yeah

short owl May 17, 2026, 6:45 PM

#

How hard was it to get that working?

icy bridge May 17, 2026, 6:45 PM

#

not that hard

#

i copied the loongarch sources (since that's a risc arch with software tlb), removed everything that didn't apply to xr17032, changed some of the exception logic, and voila

short owl May 17, 2026, 6:45 PM

#

Lol

dense vigil May 17, 2026, 6:46 PM

#

icy bridge

holy

icy bridge May 17, 2026, 6:46 PM

#

also one thing this will allow me to do is have an xr17032 VM with PCI and VirtIO devices

teal trench May 17, 2026, 6:49 PM

#

mintia xhci driver when

dense vigil May 17, 2026, 6:50 PM

#

finally acpi on xr

icy bridge May 17, 2026, 6:51 PM

#

I'd need to port edk2 first probably

#

and I guess after that and acpi the next step would be porting NT (obviously)

dense vigil May 17, 2026, 6:58 PM

#

wait

#

is that even possible

twilit smelt May 17, 2026, 6:58 PM

#

toolchain would be the hardest part

icy bridge May 17, 2026, 6:58 PM

#

if you're fine with looking at the leaked nt source it's technically possible but it was mostly a joke

#

more realistic would be a VM (within a VM) running one of the existing risc ports of NT

twilit smelt May 17, 2026, 6:59 PM

#

they made the RISC toolchains by like

#

taking the microsoft C frontend

#

and writing translators from Microsoft IR to the IR used by the vendor's toolchain

#

(so the mipsco compiler for mips, GEM for DEC Alpha, IBM's thing for PowerPC)

#

and then feeding that into the vendor backend

#

its probably possible with some reverse engineering to separate out the microsoft C frontend parts from one of the RISC compilers and patch it to emit the IR to a file or something and then do the same

#

they might even already be separate executables that already do that, i dont remember

#

it would be an insanely meticulous and annoying project though

#

brain surgery on a compiler

icy bridge May 17, 2026, 7:06 PM

#

ok so hear me out, so xr17032 has separate itlb and dtlb right? you could theoretically have an i386 interpreter in the itlb and use that to run x86 windows from the dtlb

#

the interpreter could be fairly light weight by having the dtlb miss handler directly interpret x86 ptes

#

then it's just a matter of providing drivers

twilit smelt May 17, 2026, 7:07 PM

#

i think MIPS NT is the easiest one to emulate

#

in terms of the underlying architecture being the simplest

#

and yeah youre right you could write a dtlb miss handler to walk x86 page tables

#

it would be quite obnoxious though

icy bridge May 17, 2026, 7:08 PM

#

you could make the itlb identity map and turn off the mmu whenever you need to access interpreter data

twilit smelt May 17, 2026, 7:08 PM

#

the way its designed the preferred scheme is like 3 instructions long, doing anything else requires insanely annoying code because the zero register no longer reads zero

#

aisix has an example of a non-preferred scheme because it is weird and the kernel runs from the physical address space and explicitly walks the page table

icy bridge May 17, 2026, 7:09 PM

#

damn it now I want to try making this

#

I have a problem with wanting to try anything that's theoretically feasible

twilit smelt May 17, 2026, 7:10 PM

#

https://github.com/xrarch/aisix/blob/master/src/sys/arch/limn2600/Exception.df#L503-L573

#

aisix dtlb miss handler

#

it uses a global area to save some regs which works bc its uniprocessor

#

youd need to make smarter use of the scratch CRs instead if you wanted to do it on SMP

icy bridge May 17, 2026, 7:12 PM

#

doesn't that also use some non-architectural xremu feature to alter tlb miss behavior?

#

i remember seeing something like that in the xremu source

twilit smelt May 17, 2026, 7:12 PM

#

theres a bit that causes paging to be disabled upon exceptions

#

which is how it used to always work in the like <=2020 architecture which is what aisix was written for

#

when it was changed i added that bit to be able to keep running it without having to like port it to the new scheme

#

it would not really be hard for that bit to be architectural

#

but no the tlb miss handler there by itself doesnt use any non-architectural emulator features

#

aside from the fact it is automatically running in the phys addr space

#

what i should have done is have two mmu enable bits, one for the immu and another for the dmmu

#

then you could run with the dmmu enabled and the immu off

#

alas it doesnt work that way and the 1 bit enables or disables them both

#

#

u know what would have been a cool feature is

#

split immu/dmmu enable bits

#

and split immu/dmmu disable bits which get xor'd into the former upon exceptions

#

i rectified my sins in the virtual memory design i did for the aphelion folks

#

paging is both enabled and disabled depending on the uppermost 2 address bits (out of 64)

#

rather than mode bits

shadow ridge May 17, 2026, 7:31 PM

#

what prevents user mode from jumping to an unpaged address

twilit smelt May 17, 2026, 7:31 PM

#

shadow ridge May 17, 2026, 7:32 PM

#

i see

icy bridge May 17, 2026, 7:33 PM

#

loongarch has that as wel

#

certainly seems useful

twilit smelt May 17, 2026, 7:34 PM

#

i got it from itanium i think

#

except on itanium i think that field is an index into an array of like region descriptors

#

and you can configure their base and bounds and cacheability and whatever with great detail

#

which is evil

#

and overcomplicated.

#

im looking forward to porting mintia2 to aphelion i think it will be great fun

#

the compiler infrastructure theyre doing is using jackal and xr17032 as the first test frontend and backend

#

they have a smart compiler guy and his compiler is shaping up to be like 200x fancier than mine

#

i think hes writing it first in rust and later itll be rewritten in their own lang mars once it has a mars frontend and can compile itself

#

and probably if completed itll end up being the official compiler infrastructure for xrstation too

#

bc its way better and will be able to do the same stuff

#

and still be self-hosting

#

so ill probably discard my compiler at that point

#

https://codeberg.org/orbitsystems/mars/src/branch/main/src/coyote

#

thats his jackal frontend coyote

#

it can fully parse and irgen my jackal parser which is like 5k lines

#

and use like 1/3 as much memory doing it

shadow ridge May 17, 2026, 7:46 PM

#

wtf is nuh_uh_recursive_alias

#

funniest function name ive seen

#

in decades

twilit smelt May 17, 2026, 7:48 PM

#

turns out it in C not rust

shadow ridge May 17, 2026, 7:50 PM

#

the way they do IR gen made me realize I'm a dumbass

#

and actually gives me the urge to continue my compiler project

icy bridge May 17, 2026, 7:51 PM

#

is there an xr17032 emulator test case anywhere that doesn't rely on particular hardware being installed in said emulator

#

because i'd really like to test the cpu part of all this before doing the devices part

dense vigil May 17, 2026, 7:52 PM

#

first jitted xr emulator

#

pretty cool

twilit smelt May 17, 2026, 7:54 PM

#

icy bridge is there an xr17032 emulator test case anywhere that doesn't rely on particular ...

i did a very thorough one that would run out of the rom and didnt do any IO aside from simple fetches and would only use instructions that had already been tested and would indicate progress by setting values in registers which you could inspect

#

in 2018

icy bridge May 17, 2026, 7:55 PM

#

that sounds like the exact thing i'm looking for

#

where can i find this?

twilit smelt May 17, 2026, 7:55 PM

#

2018

icy bridge May 17, 2026, 7:55 PM

#

yeah but like what repository

twilit smelt May 17, 2026, 7:56 PM

#

i assumed you knew that the architecture was entirely different in 2018 and that the only reason i mentioned that was as a self deprecating joke that i havent done any tests since then

icy bridge May 17, 2026, 7:56 PM

#

oh

shadow ridge May 17, 2026, 7:56 PM

#

i believe you might need a "time and relative dimensions in space"

icy bridge May 17, 2026, 7:57 PM

#

was that before the cisc-to-risc convertion that i seem to remember being mentioned at one point

twilit smelt May 17, 2026, 7:57 PM

#

yeah

#

but even the first risc architecture was completely different

#

so this test was for like 2 diff architectures before xr17032

shadow ridge May 17, 2026, 7:57 PM

#

twilit smelt but even the first risc architecture was completely different

i saw some code in xremu that was like

#

specific quirks

#

to make aisix work

#

because it wasnt compatible anymore

twilit smelt May 17, 2026, 7:58 PM

#

it had to be ported

#

to a totally new risc isa

#

in like early 2021

#

the new one no longer disabled paging upon exceptions

#

which was the 1 thing that needed a compatibility bit

#

#

this was the low level diagnostic rom which tested all the cpu functionality, there was also a high level diagnostic rom which would test all the devices

#

#

would be cool to make a modern version of this

#

#

jesus thats some ARCHAIC dragonfruit

#

looking thru old stuff now and i just found a heap dump from the aisix kernel debuggr

#

i forgot it would remember the routine that allocated it

#

and could look it up

#

my debugging tools have gotten lower effort with time

shadow ridge May 17, 2026, 8:19 PM

#

why do you think that is

twilit smelt May 17, 2026, 8:19 PM

#

i dont write as many bugs to start with and the ones i do write are no longer particularly challenging

#

so i havent like had occasion to improve the tools as often as i did back then

#

a project like this is really a trial by fire wrt debugging skills

#

there are so many NIH'd layers that the problem could be in

#

you learn how to narrow it down extremely quickly

#

like if i run into a confusing bug that 'makes no sense' and its a compiler bug, i almost immediately clock that its a compiler bug now just based on vibes lol

#

which has helped me outside of my toolchain as well

#

i ran into a clang bug while doing my emulator and i realized it was a clang bug very quickly and confirmed by examining the outputted assembly

#

it was a bug that had been fixed in a newer version of clang so i just updated

warm mural May 17, 2026, 8:22 PM

#

what kinda bug was it

twilit smelt May 17, 2026, 8:22 PM

#

only took me like 15 min to fix it

shadow ridge May 17, 2026, 8:22 PM

#

twilit smelt i ran into a clang bug while doing my emulator and i realized it was a clang bug...

i also saw this

twilit smelt May 17, 2026, 8:22 PM

#

me in 2019 would have had the entire emulator project derailed

warm mural May 17, 2026, 8:22 PM

#

Silent clang bugs are pretty rare

shadow ridge May 17, 2026, 8:22 PM

#

you wrote like "use a newish clang version or this wont wokr"

twilit smelt May 17, 2026, 8:22 PM

#

i really dont think id ever have found it if it were 2019 me

#

the confusing behavior would have stumped me

#

it would have taken me ages to guess it was a compiler bug

#

2025 me found it in 15 min

twilit smelt May 17, 2026, 8:23 PM

#

warm mural what kinda bug was it

i was using a calling convention they recently implemented which is designed for functions that tail call one another in a long chain

#

as i was doing in my cached interpreter

#

that call conv had a bug

warm mural May 17, 2026, 8:24 PM

#

was it musttail

twilit smelt May 17, 2026, 8:24 PM

#

it was preserve_none

#

i think

warm mural May 17, 2026, 8:24 PM

#

cuz musttail is a clang thing too but idr what it does

#

Ah it's to force TCO

twilit smelt May 17, 2026, 8:25 PM

#

shadow ridge May 17, 2026, 8:26 PM

#

btw do u use linux

#

hyena

twilit smelt May 17, 2026, 8:27 PM

#

i use macos

shadow ridge May 17, 2026, 8:27 PM

#

ah right

#

wait dont macs use arm

twilit smelt May 17, 2026, 8:27 PM

#

i was using my intel mac

#

which i will continue to use until its hard drive dies

#

due to being broke

shadow ridge May 17, 2026, 8:28 PM

#

is it an sdd

#

or hdd

twilit smelt May 17, 2026, 8:28 PM

#

hdd

shadow ridge May 17, 2026, 8:28 PM

#

ok good luck

twilit smelt May 17, 2026, 8:28 PM

#

a 12 year old hdd

shadow ridge May 17, 2026, 8:28 PM

#

i literally never had an hdd die on me before

#

the current hdds i have are probably older than me

twilit smelt May 17, 2026, 8:29 PM

#

ive had several die on me

shadow ridge May 17, 2026, 8:29 PM

#

i mean

twilit smelt May 17, 2026, 8:29 PM

#

this is the longest one has ever lasted by about 2x

#

ive been keeping backups w/ time machine because im very certain that any day now i will try to use this imac and it will just be frozen solid on IO

#

from a broken hdd

shadow ridge May 17, 2026, 8:30 PM

#

i once bent an hdd's internal disk too much and it literally did break and die on me

shadow ridge May 17, 2026, 8:30 PM

#

shadow ridge i once bent an hdd's internal disk too much and it literally did break and die o...

it also spread like metal dust everywhere

#

they dont really "bend" until they suddenly shatter

#

so yea dont play with those if you ever take one out

twilit smelt May 17, 2026, 8:31 PM

#

my mac mini i had from like 2017-2020 died a very tragic early death when the hdd died after less than 3 yrs

#

i had no backups

shadow ridge May 17, 2026, 8:31 PM

#

do macs just come with defective hdds

warm mural May 17, 2026, 8:32 PM

#

Is that your main computer

#

The Intel Mac with hdd

twilit smelt May 17, 2026, 8:32 PM

#

i started using a 2014 imac my dad had recently retired, as a "stopgap" until i could get a new computer or replace the hdd in that mac mini and its been another 6 years and im still using it lmfao

#

maining a 12 year old intel imac like a boss.

#

i may soon upgrade to a 2019 intel imac that he has sitting in his garage, which is the one that he replaced this one with, and has now itself been replaced

shadow ridge May 17, 2026, 8:33 PM

#

i would make a joke but i upgraded my system to non-dinosaur-era specs like last year

warm mural May 17, 2026, 8:33 PM

#

twilit smelt i may soon upgrade to a 2019 intel imac that he has sitting in his garage, which...

Meanwhile if stuff compiles a little too slow for my taste I immediately wanna upgrade

#

If only I weren't broke

shadow ridge May 17, 2026, 8:34 PM

#

warm mural Meanwhile if stuff compiles a little too slow for my taste I immediately wanna u...

wdym by too slow

#

im used to waiting like

#

10 mins

#

for aur packages

warm mural May 17, 2026, 8:34 PM

#

I don't like waiting for compilation

#

lol

shadow ridge May 17, 2026, 8:34 PM

#

warm mural I don't like waiting for compilation

i dont think anybody ever said "man I like waiting for compilation so much, I wish gcc was slower!"

warm mural May 17, 2026, 8:34 PM

#

It's stupid since my PC is pretty fast and Gentoo works well on it

teal trench May 17, 2026, 8:34 PM

#

i remember working on managarm on my trusty i5-3210m laptop with 4gb of ram and a 5400 rpm hdd a few years ago meme

warm mural May 17, 2026, 8:35 PM

#

shadow ridge i dont think anybody ever said "man I like waiting for compilation so much, I wi...

Idk it's probably just me complaining because zig compile times are awful

warm mural May 17, 2026, 8:35 PM

#

teal trench i remember working on managarm on my trusty i5-3210m laptop with 4gb of ram and ...

I ran Gentoo on an i3-3300m 💀

teal trench May 17, 2026, 8:35 PM

#

i booted the gentoo liveiso once on it but decided not to continue iirc :^)

shadow ridge May 17, 2026, 8:35 PM

#

my current pc randomly dies to machine checks once in a while

#

i think it's either the ram or the gpu

twilit smelt May 17, 2026, 8:36 PM

#

twilit smelt i may soon upgrade to a 2019 intel imac that he has sitting in his garage, which...

i think i will do this today

warm mural May 17, 2026, 8:36 PM

#

teal trench i booted the gentoo liveiso once on it but decided not to continue iirc :^)

It took like 18 hours for Gentoo to initially install on it

twilit smelt May 17, 2026, 8:37 PM

#

ive stretched this 2014 imac as far as it can do i believe

shadow ridge May 17, 2026, 8:37 PM

#

is it causing you any issues rn

twilit smelt May 17, 2026, 8:37 PM

#

2019 imac is still ancient but benchmarks literally 2-3x better on basically everything apparently

#

yes

#

youd probably consider the UX responsiveness im used to literally unusable

warm mural May 17, 2026, 8:38 PM

#

Imagine if will had a good computer... he would be too dangerous to be stopped

shadow ridge May 17, 2026, 8:39 PM

#

twilit smelt youd probably consider the UX responsiveness im used to literally unusable

the only reason i appear to be on discord 24/7 and respond to messages fast is because i use bspwm and just do a gliss through the keyboard to all desktops every once in a while to see what theyre doing

#

i could probably work as a full time round robin scheduler employee

twilit smelt May 17, 2026, 8:40 PM

#

warm mural Imagine if will had a good computer... he would be too dangerous to be stopped

i wanted to save up for an arm imac but the gig work im currently doing for tuition money isnt a reliable enough income stream to really save

#

i spend it all on tuition payments

warm mural May 17, 2026, 8:40 PM

#

what are you doing

twilit smelt May 17, 2026, 8:40 PM

#

its very possible im not going to upgrade to an actually modern pc until i have a full time job after i graduate

warm mural May 17, 2026, 8:40 PM

#

freelance?

shadow ridge May 17, 2026, 8:40 PM

#

hes an aibro

warm mural May 17, 2026, 8:40 PM

#

twilit smelt i wanted to save up for an arm imac but the gig work im currently doing for tuit...

arm mac mini could be good

#

Ah but then you'd need a screen

#

mhm

twilit smelt May 17, 2026, 8:41 PM

#

yeah and im way too used to 5k to give it up

#

i did the math and altogether the specs i want would only be like $50 cheaper as a mac mini setup i think

#

both were ~1200

warm mural May 17, 2026, 8:42 PM

#

You could build a PC too

#

Become a linuxbro

shadow ridge May 17, 2026, 8:42 PM

#

i can help you install arch (if you do build a PC)

warm mural May 17, 2026, 8:42 PM

#

though macs are pretty nice

#

build a hackintosh galaxybrain

shadow ridge May 17, 2026, 8:43 PM

#

build an xr station

twilit smelt May 17, 2026, 8:43 PM

#

my 2020 m1 macbook air is so much better

#

i would main it as my desktop as well if it didnt have like 512gb ssd and a small screen

warm mural May 17, 2026, 8:44 PM

#

ah yeah that'd be ideal

#

M1 is still going strong

twilit smelt May 17, 2026, 8:44 PM

#

and i dont want to buy an external 5k monitor

warm mural May 17, 2026, 8:44 PM

#

Can't you use the iMac as an external display

shadow ridge May 17, 2026, 8:44 PM

#

if an xr17032 fpga is ever made you could use it as your daily driver since linux compiles on it

warm mural May 17, 2026, 8:44 PM

#

Or did they remove that

twilit smelt May 17, 2026, 8:45 PM

#

shadow ridge if an xr17032 fpga is ever made you could use it as your daily driver since linu...

i dont want to do distro dev for xr17032

#

its my baby but i cant think of anything less interesting or more cancerous

#

ill daily drive mintia2 on amd64 or apple silicon in like 2040

shadow ridge May 17, 2026, 8:45 PM

#

well you could pull a terry davis (your favorite person) and do xr station dev on your literal xr station device

warm mural May 17, 2026, 8:46 PM

#

How is that a Terry Davis

#

Even he ran Ubuntu

shadow ridge May 17, 2026, 8:46 PM

#

he developed templeos in templeos itself

twilit smelt May 17, 2026, 8:46 PM

#

no he didnt

shadow ridge May 17, 2026, 8:46 PM

#

yes he did though

warm mural May 17, 2026, 8:46 PM

#

doubt that

shadow ridge May 17, 2026, 8:46 PM

#

the source code format is unviewable outside of temple os

warm mural May 17, 2026, 8:46 PM

#

I doubt he daily drove it

shadow ridge May 17, 2026, 8:46 PM

#

no he had ubuntu

twilit smelt May 17, 2026, 8:46 PM

#

shadow ridge the source code format is unviewable outside of temple os

huh? thats not true

shadow ridge May 17, 2026, 8:47 PM

#

and templeos running in an emulator

shadow ridge May 17, 2026, 8:47 PM

#

twilit smelt huh? thats not true

you could technically read it but it can embed other resources etc. inside of itself

warm mural May 17, 2026, 8:47 PM

#

Well that's not the same as running xr station stuff on an xr station would be

shadow ridge May 17, 2026, 8:47 PM

#

and has a lot of subscript / superscript stuff

shadow ridge May 17, 2026, 8:47 PM

#

shadow ridge and templeos running in an emulator

and he developed the os from inside the emulator

warm mural May 17, 2026, 8:47 PM

#

It's more like the NT guys dogfooding it and it sucked

shadow ridge May 17, 2026, 8:49 PM

#

warm mural Well that's not the same as running xr station stuff on an xr station would be

i mean youre right but

#

in my book this counts

#

he didnt do the development outside of it

#

outside of the initial bootstrap process

warm mural May 17, 2026, 8:50 PM

#

idk I don't think you can make a comparison between "developing the OS on the literal hardware" vs "writing code in a text editor in an emulator"

shadow ridge May 17, 2026, 8:51 PM

#

warm mural idk I don't think you can make a comparison between "developing the OS on the li...

development wise how is it any different if you simply fullscreen the emulator

warm mural May 17, 2026, 8:51 PM

#

Very

#

Because if it crashes it's way less painful to debug

shadow ridge May 17, 2026, 8:52 PM

#

didnt he use vmware

#

does that even have register dumps and shit

#

i only ever saw him use the built in debugger

twilit smelt May 17, 2026, 8:52 PM

#

warm mural It's more like the NT guys dogfooding it and it sucked

apparently dave cutler was single handedly maintaining the full screen text mode os/2 subsystem for NT (the original dogfooding environment) for like a year after everybody else had switched to the gui because he wasnt used to programming in a gui format and didnt want to change

#

he was pressured into doing it for political reasons which was that it made the gui team feel unappreciated and demoralized

#

that he wouldnt try their work

warm pine May 17, 2026, 8:53 PM

#

shadow ridge i only ever saw him use the built in debugger

a good debugger used to be regarded as essential to any kernel

twilit smelt May 17, 2026, 8:53 PM

#

and thus he switched from full screen text mode editors hed been using since 1969, to a gui code editor, for the first time

#

and never switched back

warm pine May 17, 2026, 8:53 PM

#

they faded away a bit because linus is opposed to debuggers

warm mural May 17, 2026, 8:53 PM

#

shadow ridge does that even have register dumps and shit

VMware is a commercial product

twilit smelt May 17, 2026, 8:54 PM

#

my hobby kernels have always had some kind of minimal internal debugger prompt just because it made debugging certain types of bugs way easier

warm mural May 17, 2026, 8:54 PM

#

I sure hope they do

shadow ridge May 17, 2026, 8:54 PM

#

warm pine they faded away a bit because linus is opposed to debuggers

ive never heard of that tbh

#

why does he think that

twilit smelt May 17, 2026, 8:54 PM

#

its a kernel module in mintia1 and mintia2 so that it doesnt take up any space if ur not doing kernel debugging

warm mural May 17, 2026, 8:55 PM

#

i feel like they're more moving towards supporting gdbstub vs having a bespoke debugger

twilit smelt May 17, 2026, 8:55 PM

#

the bootloader will load all the symbols and stuff for the modules in order to do its own dynamic linking of them and then they will be discarded later by the kernel if the debugger wasnt loaded

warm pine May 17, 2026, 8:55 PM

#

shadow ridge ive never heard of that tbh

https://yarchive.net/comp/linux/debuggers.html

#

he thinks it makes it too easy to write code

twilit smelt May 17, 2026, 8:55 PM

#

twilit smelt the bootloader will load all the symbols and stuff for the modules in order to d...

if it was loaded then the symbol data stays for use in tracebacks and stuff

warm pine May 17, 2026, 8:55 PM

#

maybe that's why linux doesn't allow AI generated code nowadays

shadow ridge May 17, 2026, 8:56 PM

#

it doesnt?

warm pine May 17, 2026, 8:56 PM

#

and maybe it's because torvalds thought c++98 was too complicated that linux doesn't support any more complicated languages like rust today

warm mural May 17, 2026, 8:57 PM

#

warm pine maybe that's why linux doesn't allow AI generated code nowadays

they do tho

warm pine May 17, 2026, 8:57 PM

#

warm mural they do tho

no no, they are a paragon of consistency

warm mural May 17, 2026, 8:58 PM

#

i think linus just tends to like having unpopular opinions

twilit smelt May 17, 2026, 8:58 PM

#

it sometimes makes me feel like a larper that i literally never use proper debuggers

#

all of my debugging is like 90% staring at the code 10% printfs

warm mural May 17, 2026, 8:58 PM

#

i should probably write a kernel debugger but idk if it's that useful

twilit smelt May 17, 2026, 8:58 PM

#

however im one of the best debuggers i know probably

warm mural May 17, 2026, 8:58 PM

#

i get away with just printf debugging

twilit smelt May 17, 2026, 8:59 PM

#

so i might have just learned not to do it

#

one of the only things ill like shamelessly brag about is my debugging skills

warm mural May 17, 2026, 8:59 PM

#

monkuous vs hyenasky debugging competition

twilit smelt May 17, 2026, 8:59 PM

#

i think im a like 99.9999 percentile debugger after years of this project

#

im now capable of finding really scary complicated subtle bugs in like 20 minutes

#

that would have taken me days or months a few years ago

#

i often cant even explain my process either it usually just pops into my head somehow

#

my #1 skill for sure

#

at anything

nocturne nymph May 17, 2026, 9:01 PM

#

twilit smelt im now capable of finding really scary complicated subtle bugs in like 20 minute...

...or they weren’t complicated enough 😁

twilit smelt May 17, 2026, 9:01 PM

#

perhaps

warm mural May 17, 2026, 9:02 PM

#

i feel like in a relatively complex kernel you're kinda bound to encounter pretty complex bugs

shadow ridge May 17, 2026, 9:02 PM

#

i use gdb once every 20 years to step through the code to see if the algorithm is actually working the way i read it

#

sometimes i can skim over an if statement with an incorrectly written condition and it messes up my view of the code flow

#

other than that, printf it is

twilit smelt May 17, 2026, 9:03 PM

#

one of the bugs i always mention that would 5 yrs ago certainly have taken me weeks to figure out or defeated me completely was

#

the fox32 build of mintia1 would randomly crash at random moments and only sometimes and it would change every time i built it

#

and it turned out to be that the fox32 emulator's pop instruction had a bug where if a page fault occurred while fetching a certain byte of the pop instruction, then the stack pointer could be double incremented

#

it was randomizing symptoms every time bc my toolchain at the time would lay out the code nondeterministically in the kernel binary (and every other binary) lol

#

so the pop instructions that straddled page boundaries would get moved around

#

and only sometimes do it

#

and this took me like maybe 40 min to figur eout

digital pivot May 17, 2026, 9:06 PM

#

nocturne nymph ...or they weren’t complicated enough 😁

well mintia is one of the most sophisticated kernels here in the community so it would see more complex bugs than simpler projects

twilit smelt May 17, 2026, 9:06 PM

#

it would also only happen if the pop straddled a page boundary on a certain byte and the second page was a page of pageable kernel code that had been paged out

#

so it was extremely nondeterministic

shadow ridge May 17, 2026, 9:07 PM

#

twilit smelt and this took me like maybe 40 min to figur eout

.. how

warm mural May 17, 2026, 9:07 PM

#

the fact that it only happens on fox32 probably narrows it down a ton already

#

because then you know the issue is in the arch code

#

(or the emulator in this case)

shadow ridge May 17, 2026, 9:07 PM

#

warm mural because then you know the issue is in the arch code

it could be a compiler bug as well

twilit smelt May 17, 2026, 9:07 PM

#

there was another fox32 only bug which did take me several weeks to figure out

warm mural May 17, 2026, 9:07 PM

#

right

twilit smelt May 17, 2026, 9:08 PM

#

and it turned out to be a bug in my codegen in my compiler where i was really stupidly incrementing the stack pointer to reach more distant areas, forgetting that anything below it would become volatile and could be corrupted by exception handling

#

so if an exception came in at the wrong moment during one of these spots then a confusing crash would occur

shadow ridge May 17, 2026, 9:09 PM

#

is fox32 an x86 clone

twilit smelt May 17, 2026, 9:09 PM

#

that took me a few weeks to figure out and i only figured it out because i was reading ancient usenet posts from 1991 about the i860 cpu and somebody posted "the early i860 C compiler was extremely buggy. i worked on a project based on the i860 and we had the most confusing bug and after months it turned out that the compiler was sometimes generating code that under-allocated the stack frame, and it would then get corrupted by an exception"

#

and i suddenly realized i had the exact same bug

#

went and looked and fixed it

twilit smelt May 17, 2026, 9:10 PM

#

shadow ridge is fox32 an x86 clone

its kind of like a less crufty 386

#

with a less efficient instruction encoding

shadow ridge May 17, 2026, 9:11 PM

#

why does every person who wants to make a small isa just clone i386

twilit smelt May 17, 2026, 9:11 PM

#

twilit smelt that took me a few weeks to figure out and i only figured it out because i was r...

a guy who posted on usenet like 30 years earlier told me the answer to my bug

#

there is nothing new under the sun

twilit smelt May 17, 2026, 9:13 PM

#

shadow ridge why does every person who wants to make a small isa just clone i386

i dont think that was ry's intention or even necessarily that she knew much about the 386 in particular at the time

#

i think she was just trying to do more like a z80 but 32 bit (bc she had done a lot of projects with z80 stuff) and then added paging to it later

#

and that turned out to have 386 vibes

shadow ridge May 17, 2026, 9:14 PM

#

ah

shadow ridge May 17, 2026, 9:14 PM

#

shadow ridge why does every person who wants to make a small isa just clone i386

i do still see people do this once in a while

#

like would it hurt not to have variable sized instructions and a stack machine in your isa

teal trench May 17, 2026, 9:16 PM

#

twilit smelt i think she was just trying to do more like a z80 but 32 bit (bc she had done a ...

me when z80000

#

Described at the time as a "mainframe on a chip", the processor is in many ways an equivalent to Intel's 80386.

#

truly no original idea under the sun

twilit smelt May 17, 2026, 9:17 PM

#

my favorite thing ever was when i found an oral history interview with the entire 386 chip team

#

which was done by the chm recently

#

and they spent a lot of time talking about how inferior they felt for not working on a RISC project

#

and they mentioned that they talked to a major RISC guy about the 386 and he like ripped it to shreds and they were dejected because they knew he was right

shadow ridge May 17, 2026, 9:18 PM

#

he WAS right and their project eventually turned into risc anyways

warm mural May 17, 2026, 9:19 PM

#

CISC obviously sucks... ARM is RISC and therefore much more power efficient as apple has shown!!

twilit smelt May 17, 2026, 9:19 PM

#

or no they talked to a major risc guy about the 286

warm mural May 17, 2026, 9:19 PM

#

well the 286 did suck

shadow ridge May 17, 2026, 9:19 PM

#

shadow ridge he WAS right and their project eventually turned into risc anyways

modern microcode stuff is basically just risc right

twilit smelt May 17, 2026, 9:19 PM

#

and they like proudly told him about their segmented protection model and whatever and he said "Why aren't you just doing paging with a kernel mode and user mode?"

#

and it made them feel stupid

shadow ridge May 17, 2026, 9:19 PM

#

twilit smelt and it made them feel stupid

they WERE

#

the GDT is STUPID

warm mural May 17, 2026, 9:20 PM

#

shadow ridge modern microcode stuff is basically just risc right

its more like, the distinction is useless nowadays

shadow ridge May 17, 2026, 9:20 PM

#

it's useless because they just got very good at optimizing it, no?

#

like, if i make a lua compiler that somehow makes it run as fast as optimized C code, would you say the distinction is useless

twilit smelt May 17, 2026, 9:20 PM

#

that interview was hilarious to read because of how many weird hipsters ive run into who are like "erm actually paging is ludicrously inefficient. segmentation was the right move. paging is bloat"

#

they had NO IDEA that even the 286 team thought it was STUPID before the chip even came out

#

and ALWAYS thought it was stupid

#

they felt it was a mistake that they tried putting a protected mode into the doomed 16 bit architecture at all instead of just waiting for the 386

shadow ridge May 17, 2026, 9:22 PM

#

if they were men of principal, they wouldve shelved the project and died on the spot

hollow musk May 17, 2026, 9:22 PM

#

twilit smelt it sometimes makes me feel like a larper that i literally never use proper debug...

you don't have any debugger?

twilit smelt May 17, 2026, 9:22 PM

#

hollow musk you don't have any debugger?

i dont have one with like runtime settable breakpoints and watchpoints and disassembly and stuff no

warm pine May 17, 2026, 9:22 PM

#

twilit smelt they had NO IDEA that even the 286 team thought it was STUPID before the chip ev...

this is an instance of the classic phenomenon i've spoken about before

twilit smelt May 17, 2026, 9:22 PM

#

i have one i can break into with an explicit KeBreakpoint call or with an NMI triggerable by left-alt-tab from the emulator

#

which is a prompt over serial which lets me peek and poke

warm pine May 17, 2026, 9:23 PM

#

where cult technologies (or cult tv, or whatever) is extolled for its biggest flaws

twilit smelt May 17, 2026, 9:23 PM

#

and also has some other niceties like listing threads and doing traces

warm mural May 17, 2026, 9:23 PM

#

shadow ridge like, if i make a lua compiler that somehow makes it run as fast as optimized C ...

that's literally luajit

digital pivot May 17, 2026, 9:23 PM

#

twilit smelt i dont have one with like runtime settable breakpoints and watchpoints and disas...

p sure in the industry they all have nice debuggers so have to work even harder

twilit smelt May 17, 2026, 9:24 PM

#

my debugger is slightly more capable than the original NT debugger

#

i had to use the april 1991 NT debugger while getting that R3000 build to run on MAME

#

genuinely crazy

#

i think bespoke debugger ability is inversely correlated with personal debugging skill

#

the NT guys didnt need much more than like

#

peek long

#

poke long

warm mural May 17, 2026, 9:25 PM

#

Maybe Linus was right

twilit smelt May 17, 2026, 9:25 PM

#

convert pc to symbol name

warm mural May 17, 2026, 9:25 PM

#

Debuggers are making you soft

twilit smelt May 17, 2026, 9:25 PM

#

dump registers

#

that was it

#

all they had

#

when they wrote basically the entire nt 3.1 kernel

#

which was more or less complete by 1991

#

sans bugfixes and some memory inefficient early structures that were changed to be less wasteful by rtm

shadow ridge May 17, 2026, 9:28 PM

#

warm mural Maybe Linus was right

"I'm a bastard" ~linus torvalds 2000

warm mural May 17, 2026, 9:28 PM

#

rtm?

twilit smelt May 17, 2026, 9:28 PM

#

release to manufacturing

warm mural May 17, 2026, 9:29 PM

#

ahh

nocturne nymph May 17, 2026, 9:29 PM

#

digital pivot p sure in the industry they all have nice debuggers so have to work even harder

It's certainly not that bad. Once, a bug in a pre-release CPU was found entirely without a debugger, just by looking at the code (a race condition during state saving).

twilit smelt May 17, 2026, 9:29 PM

#

markl also said at one point that on the i860 boards one of the things that made it a nightmare was that the debugger would randomly lock up after a couple commands and they literally never figured out why

#

a bug so difficult and arcane that it defeated the '89 NT team despite spending months on it they never figured it out before the entire i860 platform was dumped

#

no doubt something insane about the i860 chip

#

some errata

shadow ridge May 17, 2026, 9:31 PM

#

the way you describe it makes it sound like a cryptid

twilit smelt May 17, 2026, 9:32 PM

#

the i860 was the cryptid of 32 bit general purpose cpus

#

for 64 bit thats itanium

#

the NT team and intel's svr4 unix porting team were basically the QA group for the i860

#

they would share fixes back and forth for the like dozens of completely undocumented errata they each identified

#

nightmare chip

#

something i never understood is that like

#

at the beginning, there was no particular plan for an x86 port of NT

#

because the idea was it would ship with a new line of RISC PCs that would replace the x86 PC, so an x86 port would be a redundant waste of time because x86 already has OSes, Windows and OS/2 (which NT is meant to provide on RISC)

#

however, they did plan a MIPS port from the start, probably

#

so why didnt they just do initial NT development for the perfectly good, stable, well-developed, and battle-tested MIPS hardware that already existed (ie ~~DECstation~~ (barely existed yet, nvm) or one of the MIPSco boxes) and just plan to port it to i860 later?

#

why did they put themselves through hell with the shitty ass i860 simulator running on OS/2 and the early errata-filled dev boards

#

i believe this was actually just a straightforward mistake

twilit smelt May 17, 2026, 9:44 PM

#

nocturne nymph It's certainly not that bad. Once, a bug in a pre-release CPU was found entirely...

also hello mysterious industry person that we will politely avoid guessing the identity or company of

#

its so awesome that sometimes we get ppl with default pfp and an unidentifiable name who just start dropping lore

shadow ridge May 17, 2026, 9:47 PM

#

why do you attract so many industry people here

shadow ridge May 17, 2026, 9:47 PM

#

twilit smelt its so awesome that sometimes we get ppl with default pfp and an unidentifiable ...

they almost always exclusively chat in this thread too

nocturne nymph May 17, 2026, 9:49 PM

#

shadow ridge they almost always exclusively chat in this thread too

New old people

twilit smelt May 17, 2026, 9:49 PM

#

its probly just bc this is where a lot of the chat about industry kernel innards and history happens

shadow ridge May 17, 2026, 9:50 PM

#

sometimes i feel sad that i feel 0 drive towards history

#

it's fun reading what you write but personally i have 0 interest in the timeline of events

#

i wouldnt go out of my way to research this stuff even if you held a gun to my head

twilit smelt May 17, 2026, 9:52 PM

#

i like it because it is people who did what i like to do and its very enlightening and inspirational

#

skimming wikipedia is good but its not going to give you a 50 page report from 1990 about the performance impact of introducing a bottom-up pt walk optimization to the TB miss handler in the Alpha PALcode

#

the bowels of the CHM does have that

#

unlabeled among like 5000 other pages

shadow ridge May 17, 2026, 9:54 PM

#

if you ever get tired of mintia, you should try game dev, it's also fun stuff

digital pivot May 17, 2026, 9:54 PM

#

twilit smelt skimming wikipedia is good but its not going to give you a 50 page report from 1...

well on wikipedia you won't even find info on the more or less modern nt for example

#

even less on older stuff

shadow ridge May 17, 2026, 9:55 PM

#

will could probably revamp the NT page on wikipedia

#

and add 2 bijillion sources for it all

digital pivot May 17, 2026, 9:55 PM

#

literally 0 good pages on nt

shadow ridge May 17, 2026, 9:55 PM

#

and some dumbass mod would probably undo it and ban him

digital pivot May 17, 2026, 9:55 PM

#

ah no there was one at osdev wiki

#

it was deleted

twilit smelt May 17, 2026, 9:57 PM

#

twilit smelt unlabeled among like 5000 other pages

this is very torturous btw

#

because the knowledge that there are fascinating gems in there leads me to scan with my eyes manually over like hundreds upon hundreds of pages of extremely boring like administrative documents and budget sheets and stuff

#

and then right in the middle "Positioning Alpha AXP as the new PC architecture: a business strategy proposal"

#

or "OpenVMS versus UNIX: a kernel technology comparison", both of these internal documents that pull no punches bc theres zero marketing incentive and its meant for a narrow internal consumption

#

makes it worth the neck aches and eye strain when i find smth like that

shadow ridge May 17, 2026, 10:03 PM

#

i have no idea how you even manage to do something that doesnt give you small bits of instant gratification

#

like

#

a big project like mintia

#

you have to do a lot of work

#

before you see its fruit

#

it's really hard for me to do that type of work for extended periods of time

#

i will inevitabley get extremely bored

twilit smelt May 17, 2026, 10:05 PM

#

thats like asking how someone can go on a date with a woman even though it wont give them within 15 minutes a bunch of grown children to stand around their deathbed

#

the JOURNEY is the point.

shadow ridge May 17, 2026, 10:06 PM

#

twilit smelt thats like asking how someone can go on a date with a woman even though it wont ...

theres still bits of quick gratification along the way

#

until your baby is born ig

#

then you get hell until it actually grows up past the point where you need to actively take care

#

i think the idea of parenting is insane

#

anyways thats a bit off track

#

my point is you get joy and fullfillment from a relationship

#

but not from doing work with 0 results until a certain point is reached

twilit smelt May 17, 2026, 10:19 PM

#

i mean everything has quantifiable results in the sense that if i reimplement my kernel memory allocation scheme, i can run a bunch of benchmarks and see if it improved fragmentation and/or performance

#

that is fairly gratifying

#

theres also the qualifiable result of it just feeling nicer or prettier which is very gratifying too

mortal thunder May 17, 2026, 10:28 PM

#

icy bridge

those register names seem familiar

shadow ridge May 17, 2026, 10:32 PM

#

twilit smelt theres also the qualifiable result of it just feeling nicer or prettier which is...

hmm

#

ig youre right

#

but a lot of this stuff is like after youve already written the boilerplate

mortal thunder May 17, 2026, 10:33 PM

#

warm pine and maybe it's because torvalds thought c++98 was too complicated that linux doe...

ngl C++98 just sucked

shadow ridge May 17, 2026, 10:33 PM

#

was it really joyful to write the parts of the SDK you didnt even care about

mortal thunder May 17, 2026, 10:33 PM

#

like complete ass

blissful smelt May 17, 2026, 10:56 PM

#

warm pine https://yarchive.net/comp/linux/debuggers.html

People think I'm a nice guy, and the fact is that I'm a scheming, conniving bastard who doesn't care for any hurt feelings or lost hours of work if it just results in what I consider to be a better system.

deep

icy bridge May 18, 2026, 12:07 AM

#

i think it's ready for me to port edk2 (only half joking)

golden meteor May 18, 2026, 12:07 AM

#

well I guess I can knock that off my list of stuff to do 🤣

icy bridge May 18, 2026, 1:10 AM

#

golden meteor well I guess I can knock that off my list of stuff to do 🤣

if you want to try it out the repo is https://github.com/monkuous/xrqemu but keep in mind that the code isn't particularly well tested and that the only supported machine type doesn't match the xremu platforms at all

#

oh and the dtb that qemu provides describes an rtc device that I haven't implemented yet

twilit smelt May 18, 2026, 1:14 AM

#

icy bridge if you want to try it out the repo is <https://github.com/monkuous/xrqemu> but k...

are u doing like xr/pc

#

where its the brain of an xrstation (xr17032) and the body of a modern pc

icy bridge May 18, 2026, 1:15 AM

#

I suppose the current supported machine type somewhat matches that but it's not something I was aiming for

#

this was just the path of least resistance so to speak

#

the only xrarch device used currently is the LSIC, and I'll be using the RTC once I've implemented it

#

the rest is virtio and pcie

icy bridge May 18, 2026, 1:23 PM

#

it does indeed work

blissful smelt May 18, 2026, 1:32 PM

#

remember to tune in for next week's episode where monkuous will port windows xp to xrstation

icy bridge May 18, 2026, 1:49 PM

#

and SMP also works

#

(that's with -smp 16)

dense vigil May 18, 2026, 2:12 PM

#

icy bridge and SMP also works

This is all jitted right

icy bridge May 18, 2026, 2:12 PM

#

yeah

dense vigil May 18, 2026, 2:12 PM

#

Lol crazy

icy bridge May 18, 2026, 2:12 PM

#

you can't not jit with qemu

dense vigil May 18, 2026, 2:12 PM

#

Can you add virtio also?

icy bridge May 18, 2026, 2:12 PM

#

it's either hw accel or jit

icy bridge May 18, 2026, 2:12 PM

#

dense vigil Can you add virtio also?

this already has virtio

#

it's mostly a copy of the riscv virt board setup

dense vigil May 18, 2026, 2:12 PM

#

icy bridge it's either hw accel or jit

How difficult was it to add?

icy bridge May 18, 2026, 2:13 PM

#

it took like a few hours

dense vigil May 18, 2026, 2:13 PM

#

icy bridge this already has virtio

Damn

icy bridge May 18, 2026, 2:13 PM

#

but then xr17032 is fairly similar to existing architectures so i was able to just copy most of the code

dense vigil May 18, 2026, 2:13 PM

#

No ai? trl

icy bridge May 18, 2026, 2:13 PM

#

nope

dense vigil May 18, 2026, 2:13 PM

#

Damn

icy bridge May 18, 2026, 2:14 PM

#

this is the current hw setup https://hst.sh/nuhobidazu.yaml

warm mural May 18, 2026, 2:14 PM

#

icy bridge you can't *not* jit with qemu

isnt there a TCG interpreter

icy bridge May 18, 2026, 2:14 PM

#

i don't think so

warm mural May 18, 2026, 2:15 PM

#

it would make sense for there to be

icy bridge May 18, 2026, 2:15 PM

#

i at least haven't seen any references to it in the current source

keen stone May 18, 2026, 2:16 PM

#

how do you even know how to do stuff like this

icy bridge May 18, 2026, 2:16 PM

#

well in this case it was mostly learn-by-copying

dense vigil May 18, 2026, 2:30 PM

#

icy bridge this is the current hw setup https://hst.sh/nuhobidazu.yaml

Acpi mentioned

icy bridge May 18, 2026, 3:11 PM

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IRQs work!

dense vigil May 18, 2026, 3:20 PM

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Crazy

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Whats missing to run mintia?

icy bridge May 18, 2026, 3:26 PM

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all the xrarch hardware

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the only hw i've implemented is the lsic and rtc. mintia additionally requires kinnowfb, amtsu kb/mouse, the xrarch disk interface, and the xrarch serial interface

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they're all fairly simple devices so i don't anticipate many issues but still

dense vigil May 18, 2026, 3:28 PM

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Does the disk do DMA?

icy bridge May 18, 2026, 3:28 PM

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yeah

dense vigil May 18, 2026, 3:28 PM

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Cool

icy bridge May 18, 2026, 3:29 PM

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this is the full specification of the xrarch disk

keen stone May 18, 2026, 3:30 PM

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miles ahead from ata

dense vigil May 18, 2026, 3:30 PM

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Yeah this can be programmed in 10 minutes KEKW

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With the qemu model

icy bridge May 18, 2026, 3:32 PM

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one thing im somewhat worried about is bus error handling

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with xremu the devices can report errors from bus transactions that become bus error exceptions

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qemu doesn't have that

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so if any software relies on that behavior I won't be able to run it

dense vigil May 18, 2026, 3:33 PM

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So like MCE for example?

icy bridge May 18, 2026, 3:33 PM

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yeah

dense vigil May 18, 2026, 3:33 PM

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yeah but what sort of errors would virtualized devices even produce

icy bridge May 18, 2026, 3:33 PM

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for example if you try to set an LSIC IPL that's out of range xremu will produce a bus error

dense vigil May 18, 2026, 3:34 PM

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Maybe other arches have examples like that

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At the end of the day can't u do extern xr_raise(int nr) etc?

icy bridge May 18, 2026, 3:35 PM

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I don't know whether the qemu exception code is allowed to be called from device I/O callbacks

dense vigil May 18, 2026, 3:38 PM

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One way to find out ig ultrameme

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I mean devices can definitely raise interrupts as a result of IO

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E.g. lapic self ipi

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U can check how thats handled ig

acoustic sparrow May 18, 2026, 5:22 PM

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icy bridge qemu doesn't have that

uhh i think it does?

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iirc you can get SErrors on arm from that

twilit smelt May 18, 2026, 5:44 PM

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icy bridge so if any software relies on that behavior I won't be able to run it

The firmware depends upon bus errors to probe memory and some devices

icy bridge May 18, 2026, 5:44 PM

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just existence or actual errors?

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the former will work

shadow ridge May 18, 2026, 5:44 PM

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twilit smelt The firmware depends upon bus errors to probe memory and some devices

NEVER use manual probing unless you ABSOLUTELY MUST

icy bridge May 18, 2026, 5:45 PM

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the only issue is when a device is present but the software expects it to generate a bus error

dense vigil May 18, 2026, 5:45 PM

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@twilit smelt btw does your io stack have dma/device coherenet allocators or iommu remapping or does it do the hobby os "this raw phys addr is definitely DMAable" thing?

twilit smelt May 18, 2026, 5:46 PM

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shadow ridge NEVER use manual probing unless you ABSOLUTELY MUST

It's ok if the firmware does it in coordination with the platform designer. In fact that was a pretty common way to do device probing in like the 90s and may still be done for certain things today

twilit smelt May 18, 2026, 5:46 PM

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icy bridge the former will work

Existence

shadow ridge May 18, 2026, 5:47 PM

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twilit smelt It's ok if the firmware does it in coordination with the platform designer. In f...

it's a reference to an osdev article

dense vigil May 18, 2026, 5:47 PM

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lol

twilit smelt May 18, 2026, 5:47 PM

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shadow ridge it's a reference to an osdev article

I know it's

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is

shadow ridge May 18, 2026, 5:48 PM

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honestly limnxrstation would be much cooler if you had proper device discovery

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or plug and play even

twilit smelt May 18, 2026, 5:48 PM

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This is proper device discovery for the 90s

shadow ridge May 18, 2026, 5:48 PM

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is your goal to not make anything more advanced than the 90s

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dont you already have a few kernel design features that are way past the 90s

dense vigil May 18, 2026, 5:49 PM

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twilit smelt This is proper device discovery for the 90s

PCI was released in 1992

twilit smelt May 18, 2026, 5:50 PM

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dense vigil PCI was released in 1992

Wasn't ubiquitous until much later

twilit smelt May 18, 2026, 5:50 PM

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shadow ridge is your goal to not make anything more advanced than the 90s

xrstation is thematically tied to late 80s to early 90s workstation designs

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mintia2 is not

twilit smelt May 18, 2026, 5:52 PM

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dense vigil <@783460822525149196> btw does your io stack have dma/device coherenet allocator...

The phys mem alloc redesign to introduce zonelists for numa will have a side effect of making it really easy to add low memory zones and things like that

teal trench May 18, 2026, 5:52 PM

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dense vigil PCI was released in 1992

companies still fail at it to this day, on the rpi4 accesses to non-existent pcie devices config spaces hang for 10 seconds and then time out with an asynchronous abort

dense vigil May 18, 2026, 5:52 PM

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twilit smelt The phys mem alloc redesign to introduce zonelists for numa will have a side eff...

i meant this question more in the api sense, do you have a subsystem for allocating device-coherent memory, or remapping scatter-gather lists with the iommu (obviously stubbed if its not present) etc

twilit smelt May 18, 2026, 5:53 PM

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dense vigil i meant this question more in the api sense, do you have a subsystem for allocat...

no because mintia2 doesn't have an IO system at all yet

dense vigil May 18, 2026, 5:53 PM

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oh ok

twilit smelt May 18, 2026, 5:53 PM

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but allocating DMA channels is a thing it will have yes

dense vigil May 18, 2026, 5:54 PM

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i think this is something you should take into acount from the beginning when u start it

twilit smelt May 18, 2026, 5:54 PM

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and that comes with mapping it in an iommu and whatnot

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do not worry it's already in the plans

dense vigil May 18, 2026, 5:54 PM

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teal trench companies still fail at it to this day, on the rpi4 accesses to non-existent pci...

lol, i mean its broadcom, at least u dont get shot if u try booting anything but linux on it

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maybe thats planned for pi7

shadow ridge May 18, 2026, 5:55 PM

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teal trench companies still fail at it to this day, on the rpi4 accesses to non-existent pci...

how long till ai can do verilog and we get vibecoded hardware

icy bridge May 18, 2026, 6:02 PM

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dense vigil maybe thats planned for pi7

boot rom uses an llm to check whether you're booting linux and if you're not the TPM (Thermal overPressure Module) activates

dense vigil May 18, 2026, 6:02 PM

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im gonna blame u if they implement that

twilit smelt May 18, 2026, 7:15 PM

#

https://www.youtube.com/watch?v=tc4ROCJYbm0

YouTube

AT&T Tech Channel

AT&T Archives: The UNIX Operating System

Watch new AT&T Archive films every Monday, Wednesday and Friday at http://techchannel.att.com/archives

In the late 1960s, Bell Laboratories computer scientists Dennis Ritchie and Ken Thompson started work on a project that was inspired by an operating system called Multics, a joint project of MIT, GE, and Bell Labs. The host and narrator of t...

▶ Play video

#

i shazamed the theme at the beginning of this

#

it worked

#

https://www.youtube.com/watch?v=TDYXaandd0I

YouTube

Tony Hymas - Topic

Documentary Theme (A)

Provided to YouTube by The Orchard Enterprises

Documentary Theme (A) · Tony Hymas

Kpm 1000 Series: Miniature Theme Suites

℗ 1978 KPM Music Ltd

Released on: 1978-01-01

Music Publisher: KPM Music Ltd

Auto-generated by YouTube.

▶ Play video

#

the official unix theme song

#

is Documentary Theme (A) by Tony Hymas

shadow ridge May 18, 2026, 7:17 PM

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everything is a note ~official unix philosophy

twilit smelt May 18, 2026, 7:20 PM

#

twilit smelt https://www.youtube.com/watch?v=tc4ROCJYbm0

my eyes always get a little watery watching stuff like this cuz u can tell how much they liked their work

#

even though unix SUCKS

twilit smelt May 18, 2026, 7:30 PM

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icy bridge IRQs work!

mintia thread

icy bridge May 18, 2026, 7:34 PM

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:)

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oh also i figured out how to do the bus error thing

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turns out i was using a simplified callback and you can opt in to a better one that can return a transaction error

twilit smelt May 18, 2026, 7:37 PM

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qemu-system-xrarch

shadow ridge May 18, 2026, 7:37 PM

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you're lucky im not working on my emulator this week

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if i was, i would have already surpassed limnstation17064

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and mintia would be left in the dust

keen stone May 18, 2026, 7:38 PM

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acpi in mintia when

shadow ridge May 18, 2026, 7:38 PM

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keen stone acpi in mintia when

doesnt seem too far away tbh

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with the insane speed of monkuous' progress

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we might even get pcie mintia

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how cool is that

twilit smelt May 18, 2026, 7:39 PM

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monkuous could reuse his drivers from pc mintia

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if he made xr/pc

shadow ridge May 18, 2026, 7:40 PM

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make an extension for xr17032 called xr17032vx that adds virtualization

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so you can actually daily drive on an xr pc that runs linux on jitted x86 emulation

icy bridge May 18, 2026, 7:40 PM

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shadow ridge we might even get pcie mintia

once i have all the regular xrcomputer hardware implemented adding pcie would take like 4 lines of code (including includes and whitespace)

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qemu is very flexible

keen stone May 18, 2026, 7:40 PM

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be evil and make xr/computer be an acpi hw reduced machine

shadow ridge May 18, 2026, 7:41 PM

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nvme driver in mintia

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the feature-lack that surprises me the most is a proper audio controller

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you dont even have a beeper

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that's like the first thing i would add besides a serial device

warm mural May 18, 2026, 7:42 PM

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shadow ridge so you can actually daily drive on an xr pc that runs linux on jitted x86 emulat...

how is virtualization related to that

shadow ridge May 18, 2026, 7:43 PM

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warm mural how is virtualization related to that

xrarch jits x86

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qemu jits xrarch

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result = fast

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or something like that, idk if it would actually be faster

warm mural May 18, 2026, 7:43 PM

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there is no virtualization involved here

shadow ridge May 18, 2026, 7:44 PM

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oh right my bad

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qemu doesnt run the jitted code in a vm

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LOL

twilit smelt May 18, 2026, 7:44 PM

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shadow ridge the feature-lack that surprises me the most is a proper audio controller

its bc i dont add stuff until im ready to drive them well

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so

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when i decide to Do Audio

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that will be when i in a single sprint:

design audio controller
implement in emulator
write low level kernel driver for it
write userspace mixing server for it

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if any of those parts arent ready to be done yet (and so far #4 has been the blocker) then it wont be done yet

shadow ridge May 18, 2026, 7:45 PM

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you could add a simple beeper that the bios firmware can use

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for error codes on headless systems maybe

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idk

twilit smelt May 18, 2026, 7:46 PM

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same reason theres no like ethernet controller yet even though it wouldnt be that hard to add with like slirp or whatever, im not ready to do a net stack

icy bridge May 18, 2026, 7:46 PM

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the xremu thing where reads to nonexistent high memory return 0 instead of a bus error is incredibly annoying to implement in qemu

shadow ridge May 18, 2026, 7:46 PM

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thats weird

icy bridge May 18, 2026, 7:47 PM

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this feels incredibly hacky and i'm not even sure if it'll work properly (aka it might not return the right value)

shadow ridge May 18, 2026, 7:47 PM

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what is weirder is that it's annoying to implement

twilit smelt May 18, 2026, 7:47 PM

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but like

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theres a physaddr parameter

icy bridge May 18, 2026, 7:48 PM

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oh right i need to check that as well

twilit smelt May 18, 2026, 7:48 PM

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cant you just go if physaddr >= 0xC0000000: no failure

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(which btw is not fully correct bc the LSIC is up there and a bus error needs to occur upon LSIC nonexistence, which is how processor existence is probed)

icy bridge May 18, 2026, 7:48 PM

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the point is that i'm not sure if qemu behaves properly if i just return from that function without anything else

shadow ridge May 18, 2026, 7:48 PM

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icy bridge this feels incredibly hacky and i'm not even sure if it'll work properly (aka it...

im making an assumption that might or might not make whatever i say afterwards completely and utterly irrelevant but, assuming QEMU is using a tree to represent the physical memory space, couldnt u just fill the rest of the address space with a special memory node that always returns 0

short owl May 18, 2026, 7:48 PM

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Why does that exist btw (the no failure thing)

icy bridge May 18, 2026, 7:49 PM

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shadow ridge im making an assumption that might or might not make whatever i say afterwards c...

hm, maybe? it does have a priority thing

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might be worth looking into

twilit smelt May 18, 2026, 7:49 PM

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short owl Why does that exist btw (the no failure thing)

bc xrstation is a mosaic of design decisions made over like 8 years of everything evolving and things often dont change to be in spiritual alignment with other things that changed

shadow ridge May 18, 2026, 7:50 PM

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icy bridge hm, maybe? it does have a priority thing

if it works the way i assume it does, you could just make one node that goes from 0 to UINT32_MAX and always returns 0

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with lowest priority

icy bridge May 18, 2026, 7:50 PM

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shadow ridge if it works the way i assume it does, you could just make one node that goes fro...

it'd be 0xc0000000 to UINT32_MAX but yeah

shadow ridge May 18, 2026, 7:50 PM

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why the C

twilit smelt May 18, 2026, 7:50 PM

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uppermost 25% of the addr space

icy bridge May 18, 2026, 7:50 PM

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because below that missing memory still has to result in a bus error

shadow ridge May 18, 2026, 7:50 PM

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wtf?

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rare will L

short owl May 18, 2026, 7:51 PM

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twilit smelt bc xrstation is a mosaic of design decisions made over like 8 years of everythin...

Ok but what was the original reason for such a thing

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Like why have it at 0xC0000000

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What's there (or isn't)

twilit smelt May 18, 2026, 7:51 PM

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its where slot space starts

short owl May 18, 2026, 7:51 PM

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Ah

twilit smelt May 18, 2026, 7:51 PM

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expansion slots are mapped in increments starting there

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and they have special behavior upon accessing an empty slot

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which is to return 0

icy bridge May 18, 2026, 7:51 PM

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actually i can't do this with just a single low-priority memory region, since that doesn't quite model the behavior correctly

twilit smelt May 18, 2026, 7:51 PM

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as opposed to RAM which will time out and bus error

icy bridge May 18, 2026, 7:52 PM

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the address space is divided into 128M regions and if nothing is present in the entire region it needs to read zeroes and ignore writes, but if something is present somewhere in the region but not at the address you're accessing it needs to throw a bus error

icy bridge May 18, 2026, 7:53 PM

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twilit smelt and they have special behavior upon accessing an empty slot

which they shouldn't have btw, since the manual states:

If a card is not present in a slot, an access will result in a short timeout followed by a bus error exception. This can be used to detect if a card is present in a slot or not.

twilit smelt May 18, 2026, 7:53 PM

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yeah when writing the manual i decided to make that change

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and then

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forgot to ever make that change

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in the emulator or firmware

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i can do that now if it makes your life easier

icy bridge May 18, 2026, 7:54 PM

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that would be nice thank you

icy bridge May 18, 2026, 7:54 PM

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icy bridge the address space is divided into 128M regions and if nothing is present in the ...

i wasn't looking forward to all the hacky logic necessary to correctly model this

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especially considering i might add hotplug in the future

twilit smelt May 18, 2026, 7:54 PM

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it only impacts the firmware so its an easy enough thing to do and have the latest firmware come with the latest xremu commit so nothing breaks inbetween

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first i need to order a gigantic tuna sandwich and cinnermen role on d*oord*ash becasue im a disgusting chud

twilit smelt May 18, 2026, 7:57 PM

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twilit smelt yeah when writing the manual i decided to make that change

reason i decided to change that is its more realistic if it always bus errors

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or at least

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it would require less logic in a real hw impl

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you would need to have some kind of electromechanical indication that theres a board in a slot or not via some kind of switch

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and if theres not then youd need logic on the mobo to activate that pretends to be an endpoint device and put a 0 on the data bus and acknowledge the bus read

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which you could do

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but why

shadow ridge May 18, 2026, 8:02 PM

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icy bridge i wasn't looking forward to all the hacky logic necessary to correctly model thi...

you could have every device register 2 nodes per region

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one that does bus errors with priority 1 higher than the 0 read node

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and the other just handles the device normally with higher priority than the error one

twilit smelt May 18, 2026, 8:06 PM

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aw man thats a breaking change to mintia1

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i forgot it reprobes ebus

icy bridge May 18, 2026, 8:07 PM

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Fuck!

twilit smelt May 18, 2026, 8:07 PM

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it ok ill make that change in mintia1 nobody will notice or care

icy bridge May 18, 2026, 8:07 PM

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i also lost the race to make the change

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i was literally about to send the patches

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fuck it i'll send them anyway

📎 0001-Fw-use-bus-errors-for-ebus-detection.patch 📎 0001-remove-special-casing-for-bus-errors-above-3G.patch

twilit smelt May 18, 2026, 8:08 PM

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our xremu changes were literally identical

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but i didnt do the breakout function you did in a4x

shadow ridge May 18, 2026, 8:08 PM

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icy bridge fuck it i'll send them anyway

i cant believe you wrote these 25 years ago

twilit smelt May 18, 2026, 8:08 PM

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i did this

icy bridge May 18, 2026, 8:08 PM

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twilit smelt but i didnt do the breakout function you did in a4x

i thought it'd look a bit too messy to do it all in one function

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also if this were a real platform where actual hardware failure could occur i'd say that the bus error callback should be applied for as short a time as possible to reduce the chance of ignoring actual errors

twilit smelt May 18, 2026, 8:11 PM

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yeah its bad to have it applied across a print call

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serial or framebuffer errors could then be ignored weirdly

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i think its fine to have it applied across just pure logic though

icy bridge May 18, 2026, 8:13 PM

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yeah

twilit smelt May 18, 2026, 8:13 PM

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so i changed that

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the mintia1 change will be more interesting

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because itll need to catch the bus error exception in a way that is never done yet

icy bridge May 18, 2026, 8:13 PM

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anyway with that a4x patch qemu now errors on amtsu probing (since i haven't implemented amtsu yet)

twilit smelt May 18, 2026, 8:13 PM

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so i will be going into Ke innards

#MINTIA (not vibecoded)