[ ] Printing strings and integer numbers (both decimal and hex) on the screen is certainly a must. This is one of most basic ways of debugging, and virtually all of us have gone through a kprint() or kout in version 0.01. \
[ ] Outputting to a serial port will save you a lot of debugging time. You don't have to fear losing information due to scrolling. You will be able to test your OS from a console, filter interesting debug messages, and automatize some tests. \
[ ] Having a working and reliable interrupt/exception handling system that can dump the contents of the registers (and perhaps the address of the fault) will be very useful. \
[ ] Plan your memory map (virtual, and physical) : decide where you want the data to be. \
[ ] The heap: allocating memory at runtime (malloc and free) is almost impossible to go without. It should be implemented as soon as possible.
### Other features I am thinking of:
[ ] USTAR Filesystem ( For its simplicity this is very likely the first filesystem the OS is going to support) \
[ ] Memory Management \
[ ] Scheduling (Unknown what the scheduling algorithm will be, as with everything suspect simplicity) \
[Modern Operating Systems [book]](https://www.amazon.com/Modern-Operating-Systems-Tanenbaum-Andrew/dp/1292061421/ref=sr_1_1?__mk_nl_NL=%C3%85M%C3%85%C5%BD%C3%95%C3%91&dchild=1&keywords=Modern+Operating+systems&qid=1619967779&sr=8-1)