This document serves the purpose of measuring kernel changes since 2.4.4, in an attempt to understand what it means to port a 2.4.4 compatible application to the most recent kernel edition. That application is of course, Checkpointing/Restart As Kernel module (CRAK).
Following is a table that summarizes the relevant information:
| File | LOC 2.4.4 | LOC 2.6.25.4 | Comments |
| linux/kernel.h | 134 | 440 | |
| linux/module.h | 350 | 622 | |
| linux/fs.h | 1453 | 2102 | |
| linux/wrapper.h | 8 | N/A | |
| linux/binfmts.h | 70 | 105 | |
| linux/file.h | 101 | 124 | |
| linux/sys.h | 31 | 30 | Deprecated for 2.6 |
| linux/net.h | 229 | 346 | |
| linux/inet.h | 53 | 53 | Includes types.h in newer kernel |
| linux/devfs_fs_kernel. | 246 | N/A | What was it good for? Purpose in CRAK? |
| linux/ipc.h | 73 | 106 | |
| File | LOC 2.4.4 | LOC 2.6.25.4 | Comments |
| asm/mman.h | 39 | 42 | |
| asm/uaccess.h | 592 | 27 | get_user(), access_ok(): complexity moved |
| asm/page.h | 124 | 27 | Same as above |
| asm/ptrace.h | 64 | 172 | Moved: arch/um/include/sysdep-i386/ptrace.h |
| asm/param.h | 25 | 23 | Refactored |
| net/sock.h | 1323 | 1385 | Moved protocol specifics to ipv4,6 |
| net/tcp.h | 1824 | 1385 | |
| net/dst.h | 163 | 300 | More includes: rcupdate, jiffies. neighbors.h stays common |
| net/route.h | 170 | 211 | Added rt_cache stats |
| config.h | Seems deprecated in both versions! |