ucore is a teaching OS which is derived from xv6&jos in MIT, OS161 in Harvard and Linux.
The code in the files that constitute xv6&jos is Copyright 2006-2007 Frans Kaashoek, Robert Morris, and Russ Cox and uses MIT Licnese.
The code in the files that constitute OS/161 is written by David A. Holland.
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lab1: boot/protect mode/interrupt

boot/protect mode
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proj1       (--)        : bootloader which can switch to protect mode & print str by serial port/LPT/CGA
proj2       (proj1)     : bootloader which can read disk& elf file
proj3       (proj2)     : bootloader which reads elf OS, and elf OS which can print string

stack
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proj3.1     (proj3)     : switch to 64-bit mode, show call stack (only rbp & rip)

interrupt
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proj4       (proj3.1)   : OS can support interrupt response on serial(COM1), keyboard, timer device
proj4.1     (proj4)     : OS reset the segments(now have user text/data segments) by using LGDT, LTR instruction. prepare for proj4.1.1

user mode v.s. kernel mode
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proj4.1.1   (proj4.1)   : OS can switch between kernel mode and user mode using x86 INTERRUPT method

lab2: memory management (physic/virtual)
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proj5       (proj4.1.1) : OS can detect the physical memory space, manage physical memory using simple method in a physical memory manager framework
                          (the minimal allocated size is 4KB), can build page table
proj5.1     (proj5)     : best fit allocation (the minimal allocated size is 4KB)
proj5.1.1   (proj5.1)   : first fit(the minimal allocated size is 4KB)
proj5.1.2   (proj5.1)   : worst fit(the minimal allocated size is 4KB)
proj5.2     (proj5.1)   : buddy(the minimal allocated size is 4KB, maximal size is 4MB) memory manager

slab
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proj6       (proj5.2)   : slab memory manager for allocate/free mem size <4K (32byte ~ 128K byte)

virtual memory management structure
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proj7       (proj6)     : page fault handler & vmm struct

swap
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proj8       (proj7)     : swap in/out including page replacement method

memory map
--------------------
proj9       (proj8)     : add some simple function about memory map, such as map, unmap, dup, exit, etc.
proj9.1     (proj9)     : share memory (low level, use shmem_t)
proj9.2     (proj9.1)   : copy on write

lab3: process
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proj10      (proj9.2)   : PCB, kernel thread
proj10.1    (proj10)    : user process, read elf format file, fork, execve, load_icode, yield and a round-robin scheduler o(n)
proj10.2    (proj10.1)  : finish syscall wait, kill, exit
proj10.3    (proj10.2)  : sys_brk, manage heap
proj10.4    (proj10.3)  : sleep, add timer
proj11      (proj10.4)  : setup a kernel thread named kswapd that manage swap
proj12      (proj11)    : syscall map, unmap, and share memory (low level, share memory between parent and children); user mode thread and thread group; user mode lock (base on share memory, test bit);

lab4 scheduling
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proj13      (proj12)    : scheduling framework, and a simple First Come First Serve(FCFS) scheduling method
proj13.1    (proj13)    : RoundRobin(RR) scheduling method
proj13.2    (proj13.1)  : MultiLevel Feedback Queue(MLFQ) scheduling method (based on RR)

lab5 mutex/sync
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proj14      (proj13.2)  : semaphore in kernel
proj14.1    (proj14)    : semaphore for user process (shared among processes or threads), spipe (pipe based on semaphore/share memory)
proj14.2    (proj14.1)  : add timeout for semaphore wait
proj15      (proj14.2)  : event (with timeout)
proj16      (proj15)    : mailbox

lab6 filesystem
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proj17      (proj16)    : vfs, file, devices(stdin, stdout, null)
proj17.1    (proj17)    : pipe (anonymous pipe and fifo)
proj18      (proj17.1)  : add sfs 'simple filesystem' - only file operations (32-bit filesystem)
proj18.1    (proj18)    : add mkdir/link/rename/unlink (hard link)
proj18.2    (proj18)    : add exec
proj18.3    (proj18.2)  : add exec with arguments (at most 32)
proj19      (proj18.3)  : shell