Speaking of Forth experts -- there's Mitch Bradley, who created OpenFirmware:

https://news.ycombinator.com/item?id=21822840

Here's the interview with Mitch Bradley saved on archive.org:

https://web.archive.org/web/20120118132847/http://howsoftwar...

I've previously posted some stuff about Mitch Bradley -- I have used various versions of his ForthMacs / CForth / OpenFirmware systems, and I was his summer intern at Sun in '87!

Mitch is an EXTREMELY productive FORTH programmer! He explains that FORTH is a "Glass Box": you just have to memorize its relatively simple set of standard words, and then you can have a complete understanding and full visibility into exactly how every part of the system works: there is no mysterious "magic", you can grok and extend every part of the system all the way down to the metal. It's especially nice when you have a good decompiler / dissassembler ("SEE") like ForthMacs, CForth, and OpenFirmware do.

https://news.ycombinator.com/item?id=9271644

>DonHopkins on Mar 26, 2015 | parent | favorite | on: The Elusive Universal Web Bytecode

>The other "universal bytecode" that came out of Sun and actually has seen a lot of use is Mitch Bradley's Open Firmware Forth based boot ROMs, used by Suns' 68k, SPARC and x86 boxes, Apple's PPC Macs, IBM, ARM, OLCP XO-1, and many other systems.

>http://en.wikipedia.org/wiki/Open_Firmware

https://news.ycombinator.com/item?id=12240478

DonHopkins on Aug 7, 2016 | parent | favorite | on: “EFI? Intel has been trying to shove that down ou...

>Mitch Bradley originally developed a Forth system at Sun for use diagnosing and developing hardware, by burning it into ROM and running it via a serial port.

>It was based on Langston and Perry's Forth-83, and had a meta compiler that could target different word sizes and architectures. He made it even more architecture and word size independent, implemented interactive top level loops and conditionals, emacs-like line editing, all kinds of low level device drivers and testers that ran in stand-alone mode, and many other features, including full 16 and 32 bit support with a vocabulary for writing word size and endian independent code.

>He ported Sun Forth to 68K and SPARC Sun workstations, as well as the Amiga and other systems. It ran in both stand-alone mode (from disk, tftp or ROM), or under Unix. Under Unix, it could dynamically relocate and link in Unix libraries, and you could call back and forth between Forth and C.

>Sun Forth eventually evolved and standardized into the Open Firmware [1], whose purpose was to support machine independent byte code [2], so plug-in hardware cards could include ROMs with Forth byte code drivers that ran on 68K, SPARC, x86 and other systems.

>Sun shipped it with the SPARC workstations, Apple adopted it and shipped it on their PowerPC Macs, IBM shipped with their POWER servers, and Mitch worked directly with the OLPC project extending OpenFirmware to support the OLPC XO-1 Children's Computer secure and power efficient hardware. [3]

>>OLPC Wiki: Open Firmware

>>Open Firmware is the hardware-independent firmware (computer software which loads the operating system) that the XO runs.

>>It was developed by Mitch Bradley at Sun Microsystems, and used in post-NuBus PowerPC-based Apple Macintosh computers (though it has been dropped with Apple's transition to Intel processors), Sun Microsystems SPARC based workstations and servers, IBM POWER systems, and PegasosPPC systems, among others. On those computers, Open Firmware fulfills the same tasks as BIOS does on PC computers.

>>For example Fedora and Debian use the YaBoot BootLoader for Open Firmware.

>>The Open Firmware user interface includes a FORTH-based shell interface. FORTH is a powerful high level language that is remarkably compact. A complete Forth development environment including compiler, decompiler, assembler, disassembler, source level debugger, and assembly language debugger is present in the XO boot ROM (SPI FLASH). With the Open Firmware Forth system, you can directly access all of the hardware devices on the XO, use built-in functions like selftest diagnostics and games, and even write complete applications, without needing any external tools. The bulk of Open Firmware is written in Forth, so the source level debugger can be used to debug Open Firmware itself.

>[1] http://www.openfirmware.info

>[2] http://www.openfirmware.info/FCODE_suite

>[3] http://wiki.laptop.org/go/Open_Firmware

https://news.ycombinator.com/item?id=15040859

>DonHopkins on Aug 17, 2017 [-]

>Emacs qualifies as a window manager in my book! ;)

>That code you linked to is from Mitch Bradley's "Forthmacs", which ran on Sun workstations including 68k i86 and SPARC, and also Atari ST, Mac and other systems. He developed it into the "Open Boot ROM" architecture, which was used in Sun workstations and Apple PowerPC Macs as well as the OLPC children's laptop.

>https://github.com/ForthHub/ForthFreak/blob/master/Forthmacs

>https://en.wikipedia.org/wiki/Open_Firmware

>http://wiki.laptop.org/go/Open_Firmware

>On SunOS, Forthmacs had a library clink.f with the ability to dynamically relocate and link Unix libraries so that you could call them from Forthmacs, pass arguments on the stack, etc. SunOS didn't actually support shared libraries or dynamic address relocating at that time, so Forthmacs simply ran the Unix linker utility to create a file with the library relocated to the desired address space in the FORTH dictionary, and then read that file into memory, define its symbols in the FORTH dictionary, and let you access its variables and call its functions directly from FORTH!

>That's how Mitch originally integrated MicroEmacs with Forth to make Forthmacs, and how I later integrated "uwm" into FORTH: I refactored uwm so instead of having an event loop in the main function, it was a library that could be called by FORTH, which would link the library in and run the main loop itself, calling into the library as needed to initialize and handle specific events (_uwm_init, _uwm_poop).

http://www.donhopkins.com/home/archive/piemenu/uwm1/fuwm-mai...

>Here's the glue that links in the uwm library from fuwm.out:

http://www.donhopkins.com/home/archive/piemenu/uwm1/load-fuw...

.( Loading...) cr
requires tasking.f
requires uwm.f
requires clink.f
.( Linking...) cr
"" fuwm.out clink
.( Linked!) cr

https://news.ycombinator.com/item?id=17480298

>DonHopkins on July 7, 2018 | parent | favorite | on: Tali Forth 2 for the 6502

>Cool! Does it include a FORTH 6502 assembler written in FORTH? I love writing assembly code in RPN with Forth macros!

>You can write FORTH code with loops and conditionals and any kind of logic and parameters, that dynamically assembles machine code! Much better than your typical macro assembler.

>Here's some 6502 assembler for an Apple ][ SUPDUP terminal emulator that does ram card bank switching:

>http://www.donhopkins.com/home/archive/forth/supdup.f

>Here's some Forth 68k assembler that draws lines on a weird Sun-2 CGONE graphics board.

>http://www.donhopkins.com/home/archive/forth/cg/bline.f

>Mitch Bradley's 68k forth lets you use interactive conditionals and loops in the top level outer interpreter!

>I think he wrote a paper about that feature, which I might be able to dig up ... Here's something related he wrote about refactoring the outer interpreter, but not what I'm thinking of:

https://groups.google.com/forum/#!topic/comp.lang.forth/lKQj...

>avhon1 on July 7, 2018 [-]

>> Does it include a FORTH 6502 assembler written in FORTH?

https://github.com/scotws/TaliForth2/blob/master/docs/manual...

>>Currently, there is no assembler included. The plan is to include a simple assembler based on Simpler Assembler Notation (SAN).

>It does include a disassembler: https://github.com/scotws/TaliForth2/blob/master/docs/ch_dis...

>The author has written a 6502 assembler in gforth: https://github.com/scotws/tasm65c02

>Here is a document describing the notation: https://docs.google.com/document/d/16Sv3Y-3rHPXyxT1J3zLBVq4r...

>DonHopkins on July 7, 2018 [-]

>I got a quick reply from Mitch Bradley!

>Yes I wrote a paper but I probably can't find it. The easiest place to look would be in the Open Firmware source.

>https://github.com/MitchBradley/openfirmware/blob/master/for...

>The magic is all in +level and -level. Search for those in kernel.fth to see other places they are used to achieve a similar effect, e.g. in abort"

>For an alternative but effectively equivalent formulation, see:

>https://github.com/MitchBradley/cforth/blob/master/src/cfort...

>and

>https://github.com/MitchBradley/cforth/blob/master/src/cfort...

lukego on Dec 18, 2019 [–]

I love your posts about this stuff :)

I was also an "intern" of sorts for Mitch as recently as 2009 or so. I wrote the audio driver for OLPC XO 1.5 and went to Taipei to help with the bringup. I was amazed to watch Mitch using Forth to interactively tweak the DDR memory settings, find bugs in the motherboard, and find bugs in the CPU which was a godawful x86 from VIA that had seemingly only been debugged enough to boot windows :)

DonHopkins on Dec 18, 2019 | parent [–]

That must have been a fun and unique opportunity! His programming and debugging process has to be seen to be believed. OpenFirmware is definitely a highly polished work of love. Its well-commented and meticulously organized source code reads like fine literature or classical music! Stuff like the metacompiler and kernel, for example:

https://github.com/MitchBradley/openfirmware/blob/master/for...

https://github.com/MitchBradley/openfirmware/blob/master/for...