If you are interested in security then you need to be aware of the techniques that hackers can use to find out how your applications work.
Thinking about trace methods made me remember my good friend Phil's program libtrace that was written a few years ago. Phil wrote the C and PowerPC assembler code to hook calls made to functions in dynamic link libraries for IBM AIX 4.3 and higher. This enabled Phil to get truss like functionality for the IBM. The code is available on Phil's companies page Useful Programs and Scripts. libtrace is included along with some other useful programs, for instance inf_vgda that Phil wrote to allow the manipulation of the VGDA area of a LVM managed physical disk. This all means that you can hot swap disks (as Phil says, "if you know what you ar doing").
Another program that is of interest is rsb also written by Phil that allows the superblock of a jsf file system to be read and dumped. This includes inodes of files that have been deleted. If this is the case and the physical space has not be overwritten it allows files to be "undeleted". This can be useful if something is deleted and you need it. But also remember that someone else could "undelete" files or data that you thought had been deleted.