ucore is a teaching OS which is derived from xv6&jos in MIT, OS161 in Harvard and Linux.
ucore was developed and used in Department of Computer Science & Technology, Institute for Interdisciplinary Information Sciences, Tsinghua University.
The codes in the files that constitute xv6&jos are Copyright (2006-Current) Frans Kaashoek, Robert Morris, and Russ Cox and uses MIT License.
The codes in the files that constitute OS/161 are written by David A. Holland.
The codes in the files that constitute ucore are Copyright (2010-Current) Yu Chen, Naizheng Wang, Yong Xiang and uses GPL License.
The documents in the files that constitute ucore are Copyright (2010-Current) Yu Chen, Yong Xiang and uses Creative Commons Attribution/Share-Alike (CC-BY-SA) License.
You can download this virtual disk image -- oslabs_for_student_2012.zip (576.2MB,) from http://pan.baidu.com/share/link?shareid=69868&uk=2585194235, which
is an VirtualBox disk image (contains ubuntu 12.04 and needed softs, and is zipped with zip and xz format), and can be unzipped
by haozip software (http://www.haozip.com).
After unzip oslabs_for_student_2012.zip, you will get
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C:\vms\ubuntu-12.04.vbox.xz
C:\vms\ubuntu-12.04.vmdk.vmdk.xz
C:\vms\ubuntu-12.04.vmdk-flat.vmdk.xz
---
then you will continue unzip all these files, and get
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C:\vms\ubuntu-12.04.vbox
C:\vms\ubuntu-12.04.vmdk.vmdk
C:\vms\ubuntu-12.04.vmdk-flat.vmdk
---
If you installed VirtualBox soft, then the last step is: double clik file "ubuntu-12.04.vbox" and run ubuntu 12.04 in VirtualBox.