GNU/Linux Running On An 8-Bit Processor
dartttt writes, quoting Ubuntu Vibe: "Dmitry Grinberg has successfully booted Ubuntu 9.04 on an 8 bit micro machine with 6.5 KHz CPU and 16 MB RAM. Grinberg did this experiment on a ATmega1284p, 8-bit RISC microcontroller clocked at 24MHz and equipped with 16KB of SRAM and 128KB of flash storage. Since the RAM was too low, he added 30-pin 16MB SIMM to the machine and a 1 GB SD card to host Ubuntu image. ... To get the world's slowest Linux Computer running, he had to write an ARMv5 emulator which supports a 32bit processor and MMU. A similar machine can be made very easily and everything should come in about $20."
There is source code available, but it's under a non-commercial use only license. Just how slow is it? "It takes about 2 hours to boot to bash prompt ('init=/bin/bash' kernel command line). Then 4 more hours to boot up the entire Ubuntu ('exec init' and then login). Starting X takes a lot longer. The effective emulated CPU speed is about 6.5KHz, which is on par with what you'd expect emulating a 32-bit CPU & MMU on a measly 8-bit micro. Curiously enough, once booted, the system is somewhat usable. You can type a command and get a reply within a minute." If you like watching a whole lot of nothing, there's a video of the boot process below the fold.
Nice trick. However, let me point out that in 1990 Geoworks GEOS was capable of running a preemptive multitasking GUI looking much like QT but with better automatic widget layout, on an 8 MHz 8088. I will just heave a great sigh in the name of the lost art of tight coding. No, Linux is not tightly coded. I should know. The best you can say about it is, the other guys are worse.
Have you got your LWN subscription yet?
No version of windows ever ran on an 8-bit processor. Windows 1.0-3.0 would run on an 8086, but that is still 16-bit, and Windows 3.1 won't even run on that, it needs a 286 or higher.
I was bored :)
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1. Enjoy your job
2. Make lots of money
3. Work within the law
Choose any two.