Everything dmux said, adding the fact that Forth can be implemented by extremely simple and compact code, think of it as the smalltalk of the embedded world (For instance Apple bios - open firmware - give the user a Forth REPL)
[1] https://en.wikipedia.org/wiki/Open_Firmware
[2] https://en.wikipedia.org/wiki/Mitch_Bradley
In fact: the Open Firmware boot loader and plug-in card firmware interface technology, commonly used by both Sun and Apple, is the only firmware standard in existence to ♫ have its own theme song ♫ [3] !!!
[3] https://web.archive.org/web/20070204145613/http://playground...
: OpenFirmwareSong ( 🎸- ♬ )
\ By Mitch Bradley.
\ Sung to the tune of "The Flintstones".
𝄞
." Firmware" cr
." Open Firmware" cr
." It's the appropriate technology," cr
." Features" cr
." FCode booting" cr
." Hierarchical DevInfo tree." cr
." Hack Forth" cr
." Using Emacs on the keys," cr
." Save in" cr
." NVRAM if you please." cr
𝄒 cr
." With your" cr
." Open Firmware" cr
." You can fix the bugs in no time" cr
." Bring the kernel up in no time" cr
." We'll have an FCode time!" cr
𝄒 cr
\ Thank you and good night!
reboot
;OpenFirmware is one of the main inspirations for the design of Snabb Switch too. I was impressed that Mitch writes his own drivers faster than most people can integrate off-the-shelf ones. He sets a great example of getting more done by making a habit of self-sufficiency instead of accumulating ever more dependencies and keeping them up to date.
Relevant blog entry: http://lukego.github.io/blog/2012/10/28/firmware-vs-software...
I worked with Mitch on "bringup" of the OLPC 1.5 hardware and got to see him doing amazing things. The best was when he needed to initialize the memory controller to make RAM available and so he flashed a small Forth system that could run strictly within cache and then connected to that with a serial port and poked the memory controller registers until he had the RAM working. Made an impression on me :-).
ps: I did buy a Mac Mini with the idea that I could play with bare metal Forth.