Not really, the processor has to be designed to support it that way to make it practical. With interrupts, execution can be interrupted at any point, and you have to be able to restore the registers to the correct state before letting the process continue from that point. It's technically doable, but with a chip that has only 128 bytes of RAM, you'll be pretty limited in how many processes you can run. Even Windows, prior to Win95, used the event loop style for multitasking.