ikOS Reference Manual¶
ikOS is a small multitasking kernel for 8-bit Atmel/Microchip AVR microcontrollers, written in the ik language and built with the ik8b toolchain. It boots into an interactive shell over the UART, with a tiny scripting language, a hierarchical filesystem on the on-chip EEPROM, and commands for files, processes, memory, GPIO, and the serial buses (UART/SPI/I2C/ADC).
It targets the atmega32 and atmega328p out of the box and fits in
32 KB of flash with a few hundred bytes of SRAM. Scheduling is cooperative:
each process runs until it yields, and a Timer0 tick drives up and timed
sleeps. ikOS is not a hard real-time OS — there is no preemption or priority
scheduling.
This manual is organised into three parts: a user guide (build it, drive the shell, write scripts, use storage), a kernel internals section (boot, scheduler, memory map, filesystem, drivers), and a reference (the full command set).
Meet Iki
Iki is the ikOS mascot — an ant.
Why an ant? Ants are tiny, yet together they accomplish feats far beyond their size: they carry many times their own weight, build, forage, and defend as one. They manage it through cooperation and union — no ant is in charge; each does its small part and yields to the colony. ikOS works the same way: a kernel small enough to fit in 32 KB, where processes are scheduled cooperatively, each yielding the CPU to the others so that, together, the little system does real work. Small, collaborative, capable — that is Iki.
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(o o)
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/ | | \
A first session
ikOS 0.1.0 Sauva GPL-3.0+
/$ mkd etc
/$ cd etc
/$ say hello >> motd
/$ cat motd
hello
/$ cd /
/$ ls
/
`-- etc/
`-- motd
Kernel internals
Appendix