caps zonder size limit?
invoke ipc: try sync; try receiver memory; try caller memory; fail.

memories map:

top
- lcd
- keyboard
- sound
- led
- udc
- battery
- beeper
- msc
- nand
- filesystem
- network
- top session manager
- - user session
- - - program container
- - - - driver emulation
- - - - driver emulation
- - - - program
- - - program container
- - - - driver emulation
- - - - program
- - user session
...

te doen:
- caps in init met een cap per process
- die cap bevat caps in target memory met een cap per service
- die cap bevat een user van de service
- sysreq is geen aangeboden service, usbfs wel
- sysreq schakelt tussen running processes incl. user switching.

- display interface: put pixel commando
- typewriter: print toetsen op scherm; shell?

- terminal
- emulaties automatisch per proces
- start programma van filesystem
- nand driver
- filesystems met backing store

Boot process:
- bootinit and filesystem (and backing store) are started.
- bootinit starts run.elf and loads init.elf.
- run starts init.
- init loads init.config and executes it.
- during that process, the initial programs are killed.

Order:
run.elf
init.elf
init.config
load.elf
drivers
emulations
programs

init.config is a script:

	# load <name> = <filename>			load a file into memory.  Don't use this after killbootthreads.
	load session = session.config
	load driver_lcd = lcd.elf
	load driver_buzzer = buzzer.elf
	load driver_gpio = gpio.elf
	load driver_audio = audio.elf
	load driver_udc = udc.elf
	load driver_nand = nand.elf

	load emu_lcd = emu_display.elf
	load emu_buzzer = emu_buzzer.elf
	load emu_keyboard = emu_keyboard.elf
	load emu_audio = emu_audio.elf
	load emu_udc = emu_udc.elf

	# killbootthreads				destroy bootinit, bootfs and bootstore.
	killbootthreads

	# receive <cap> = <name> (<type> [, <index>])	prepare to accept a capability from a named program.
	receive display = driver_lcd (display)
	receive display_bright = driver_lcd (setting)
	receive buzzer = driver_buzzer (buzzer)
	receive keyboard = driver_gpio (keyboard, 0)
	receive sysreq = driver_gpio (keyboard, 1)
	receive audio = driver_audio (audio)
	receive udc = driver_udc (udc)
	receive nand = driver_nand (wstring)

	# driver <name>					run a previously loaded program priviledged.
	driver driver_lcd
	driver driver_buzzer
	driver driver_gpio
	driver driver_audio
	driver driver_udc
	driver driver_nand

	# wait						wait until all expected capabilities are received.
	wait

	# sysreq <cap>					use a capability as the system request keyboard.
	sysreq sysreq

	# give <name> (<type> [, <index>]) = <cap>	give this capability to this program when it requests it.
	give emu_display (display) = display
	give emu_display_bright (setting) = display_bright
	give emu_buzzer (buzzer) = buzzer
	give emu_keyboard (keyboard, 0) = keyboard
	give emu_audio (audio) = audio
	give emu_udc (udc) = udc

	# run <name>					run a previously loaded program (normally).
	run emu_lcd
	run emu_buzzer
	run emu_keyboard
	run emu_audio
	run emu_udc

	# include <name>				include a loaded file as another config file.
	include session

	# loop						sit and do nothing (respond to system request).
	loop