The operating system you will build, called JOS, will have Unix-like functions, but is implemented in an Exokernel style (i.e., the functions are implemented mostly as user-level library instead of built-in to the kernel).
Lab Setup Guide
Lab 1: Booting a PC
Lab 2: Memory Management
Lab 3: User Environments
Lab 4: Preemptive Multitasking
Lab 5: File System and Shell (Optional)