confused about the organization of the kernel code

[Zhongjie Zhu <zhuzj.netbsd%gmail.com@localhost>]

Hi,
I was studying some code of NetBSD kernel recently, I found that it is
hard to find where the certain code is located,
for example, there are three directories for file system, ufs, fs,
miscfs, and there are more directories in arch directory
for a certain CPU. why not move them into one directory? Is there any
plan to reorganize the directories?

thanks.