Ilo – a Forth System Running on Uefi
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The post showcases Ilo, a Forth system running on UEFI, sparking discussion about its potential as a command-line shell and its relation to historical systems like Open Firmware.
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Any idea why crc is specifying a custom BIOS image? QEMU comes with a default one, right? Questions like these make me wish asciinema supported recording voiceovers.
I'm guessing that the slow text screen updates are some kind of an artifact of unoptimized UEFI implementation, and/or QEMU, because I'm pretty sure Konilo is a lot snappier than this running under Linux, even though the Ilo implementation is not a highly optimized virtual machine.
I can say that the display & overall performance is noticeably faster on the two actual computers I tested on than under qemu on my Linux system.
It makes sense that it would default to using SeaBIOS; QEMU has a lot of options whose defaults were more reasonable 20 years ago.
I don't think you can make those small tweaks without breaking tens of thousands of users' production setups which depend on those defaults.
The approach the project has settled on is to say that providing user friendly defaults should be the job of a "management layer" piece of software like libvirt, and QEMU proper should concentrate on providing flexible and orthogonal options which that other software can use to tell it what to do.
But in this case, my suggestions should be fairly backwards compatible; retaining the default of BIOS but adding a simple `--firmware uefi` option would change nothing for existing users, and even defaulting to `--firmware uefi,bios` should be mostly compatible since it just tries UEFI and then promptly falls back to BIOS.
New top level command line options are rare these days, and magic "do what I mean" options also rare: we tend to prefer "tell us specifically what you want".
You'd probably want to use `-enable-kvm` so it's not doing full software emulation. Assuming you're running this on another x86-64 machine.
see https://old.reddit.com/r/osdev/comments/yjm04z/vga_on_uefi/i...
It's rather concise, most functions tend to be a single short line. Its syntax is minimal (or non-existent according to some), it's just flat white-space separated tokens. It has imperative/interactive semantics, in the sense that every successive word makes some changes on the current state (the stack).
All of this makes it quite amenable to be used as an OS shell I think, it seems obvious in retrospect.
The idea of starting with an empty Forth and creating a whole universe of automations and DSLs for your system, one command at a time, is quite pleasing, in a purist sense, although perhaps not entirely practical.
Does such a shell exist? Not as minimal as Ilo, one you can actually use in a modern system instead of bash and the like, ideally with a nice display of the stack. Probably Factor is the most appropriate Forth-like to build it on, it already has a good REPL mode, it would mainly involve adding a bunch of utilities for practical command-line use.
For a reference, the 8088 build needs a bit more than that to account for stacks, the VM code, drivers, and memory needed for the actual hardware. (Around 384KiB physical RAM on an 8088/8086 works well from my testing, but I've tested with 285-320KiB in non-standard configurations under a few emulation targets).
I use RetroForth as a working environment on Unix [mostly OpenBSD & FreeBSD], with an (unreleased) userland written in it, along with some use of external standard utilities. I'm still working on improvements around chaining programs via a pipe-like structure, but it's been my main environment apart from Konilo for a few years now.
I went through a short period of figuring out interesting peek/poke memory addresses for modifying the BASIC system, and found the "80" used as the scroll width. Setting that to 60 allowed me to create a non-scrolling status sidebar like that for my first programs/games.
It strikes me that it would have been great to have had a Forth machine back then. That early version of BASIC didn't have a (language accessible) stack! Not even a return address stack, aka GOSUB. So I used strings as a stack to implement a small text adventure parser. (And later, on a computer with graphics pixels, I used BASIC strings as a heap for defining and drawing simple 3D vector objects.) Then I learned Pascal.
Desperate times. Desperate measures. But Forth would have been great.
https://www.acornelectron.co.uk/info/electron/acornsoft_adde...
I still have mine
[1] https://www.jupiter-ace.co.uk/
https://github.com/so-dang-cool/dt
https://github.com/mitchpaulus/mshell
(I wonder how they got that acronym)
* https://en.wikipedia.org/wiki/Open_Firmware
* https://apple.fandom.com/wiki/Open_Firmware
https://www.youtube.com/watch?v=b8Wyvb9GotM
>You may be amused to know that the firmware has an Easter Egg of the Conway's Life. If you press the rocker pad (left side of screen) to the right after powering on, you will get a randomly-select amusement, one of which is Life. It uses the traditional life-death rule with a wrap-around field, and initial conditions that result in a fairly long number of generations before steady-state. Specificially, the initial state is a glider gun and an R-pentomino. The pentomino evolution eventually wrecks the gun, but things get pretty wild for awhile as gliders wrap around and interact with the debris from the pentomino. It almost stabilizes several times, but then something will set off another burst of activity for awhile before it finally dies out.
https://news.ycombinator.com/item?id=21049568
DonHopkins on Sept 23, 2019 | parent | context | favorite | on: OLPC’s $100 laptop was going to change the world (...
That's Mitch Bradley's Open Firmware Forth, which was also on Suns, post-NuBus PowerPC Macs, Pegasos, and IBM Power Systems!
I used to call it "L1-A Forth", because that's the Forth you got when you pressed "L1-A" on a Sun keyboard to get into the boot monitor. He also made a great version of that Forth system with a metacompiler that ran under Unix (Forthmacs), which I used a lot.
https://github.com/MitchBradley
https://github.com/MitchBradley/openfirmware
https://en.wikipedia.org/wiki/Open_Firmware
https://web.archive.org/web/20121119070656/https://elinux.or...
http://macos9lives.com/smforum/index.php?topic=1965.0
https://github.com/ForthHub/ForthFreak/blob/master/Forthmacs
Also:
https://news.ycombinator.com/item?id=38689282
>Mitch Bradley came up with a nice way to refactor the Forth compiler/interpreter and control structures, so that you could use them immediately at top level! Traditional FORTHs only let you use IF, DO, WHILE, etc in : definitions, but they work fine at top level in Mitch's Forths (including CForth and Open Firmware).
More about Mitch and OpenFirmware:
https://news.ycombinator.com/item?id=29261810
https://web.archive.org/web/20090920123423/http://radian.org...
>And lest you think this is some kind of Apple-paid rant, I'll mention Mitch Bradley. Have you read the story of Mel, the "real" programmer? Mitch is that guy, in 2008. Firmware superhacker, author of the IEEE Open Firmware standard, wrote the firmware that Sun shipped on its machines for a good couple of decades, and in general one of the few people I've ever had the pleasure of working with whose technical competence so inordinately exceeds mine that I feel I wouldn't even know how to start catching up. Mitch's primary laptop runs Windows.
So your temporary top level code is out of the way of HERE and can compile permanent stuff into the dictionary or whatever it needs to do. Then you can do stuff like "10 0 do i , loop" and the numbers you're ,'ing won't get mixed up with the code of the loop that's ,'ing them.
This post has a bunch of links to the OpenFirmware metacompiler's implementation and also the CForth implementation:
https://news.ycombinator.com/item?id=38689282
Here are the control structures in kernel.fth (this is some beautiful FORTH code to read for pleasure):
kernel.fth: https://github.com/MitchBradley/openfirmware/blob/master/for...
Here is the same approach in CForth, the low level C kernel code (necessarily ugly C macrology) and the higher level FORTH control structure definitions (more beautiful FORTH code):
forth.c: https://github.com/MitchBradley/cforth/blob/master/src/cfort...
control.fth: https://github.com/MitchBradley/cforth/blob/master/src/cfort...
Here is another paper about refactoring the FORTH compiler/interpreter with deferred words that Mitch wrote called "Yet Another Interpreter Organization":
https://groups.google.com/g/comp.lang.forth/c/lKQjcJL_o54/m/...
>There has been a mild controversy in the Forth community about how to implement the text interpreter. The particular problem is how the distinction between compiling and interpreting should be coded. At least three distinct solutions have been advocated over the years. I propose a fourth one, and claim that it is the best solution yet.
[describes FIG-FORTH's solution with STATE, PolyForth's solution with two separate loops for compiling and interpreting, Bob Berkey's coroutines approach]
>What is Wrong with all this
>These different schemes do not at all address what I consider to be the fundamental problems with the interpreter/compiler.
>Fundamental Problem #1:
>The compiler/interpreter has a built-in infinite loop. This means that you can't tell it to just compile one word; once you start it, off it goes, and it won't stop until it gets to the end of the line or screen.
>Fundamental Problem #2:
>The reading of the next word from the input stream is buried inside this loop. This means that you can't hand a string representing a word to the interpreter/compiler and have it interpret or compile it for you.
>Fundamental Problem #3:
>The behavior of the interpreter/compiler is hard to change because all the behavior is hard-wired into one or two relatively large words. Changing this behavior can be extremely useful for a number of applications, for example meta-compiling.
>Fundamental Problem #4:
>If the interpreter/compiler can't figure out what to do with a word (it's not defined and it's not a number), it aborts. Worse yet, the aborting is not done directly from within the loop, but inside NUMBER. This severly limits the usefulness of NUMBER because if the string that NUMBER gets is not recognizable as a number, it will abort on you. (The 83 standard punts this issue by not specifying NUMBER, except as an uncontrolled reference word).
[describes Mitch's solution of making DO-DEFINED, DO-LITERAL, and DO-UNDEFINED a deferred word]
>So what?
>This may seem to be more complicated than the schemes it replaces. It certainly does have more words. On the other hand, each word is individually easy to understand, and each word does a very specific job, in contrast to the old style, which bundles up a lot of different things in one big word. The more explicit factoring gives you a great deal of control over the interpreter.
[describes cool examples of what you can do with it]
>Finally, a really neat way to write keyword-driven translators. Suppose you have some kind of a file that contains a bunch of text. Interspersed throughout the text are keywords that you would like to recognize, and the program should do something special when it sees a keyword. For things that aren't keywords, it just writes them out unchanged. Suppose that the keywords are ".PARAGRAPH", ".SECTION", and ".END". [...]
>I have used this technique very successfully to extract specific information from data base files produced by a CAD system. Instead of outputting unrecognized words, I actually just ignored them in this application, but the technique is the same in either case.
Mitch had the coolest P.O. Box address for his Forthware company in Mountain View!This deferred word approach is actually what I used for the HyperTIES markup language interpreter/formatter for NeWS I wrote in Forth and C and PostScript, using Mitch's Sun Forth / Forthmacs (predecessor to OpenFirmware that ran on the Sun):
https://donhopkins.com/home/ties/doc/formatter.st0
https://donhopkins.com/home/ties/fmt.f
https://donhopkins.com/home/ties/fmt.c
https://donhopkins.com/home/ties/fmt.cps
https://donhopkins.com/home/ties/fmt.ps