AIX is an IBM mainframe operating system of the 1970s that is cruelly trapped in
the body of a UNIX system. Although the UNIX plumbing keeps the system run-
ning, AIX has no particular interest in being UNIX or in following UNIX conven-
tions. It employs a variety of hairpieces, corsets, and makeup kits to project an
image more consistent with IBM’s taste. It’s an open, modular system that longs to
be closed and monolithic.
Those who approach AIX as UNIX will discover a series of impediments. AIX
does not really trust administrators to understand what they are doing or to di-
rectly modify the system. Instead of simplicity, modularity, and flexibility, AIX
offers structure. Considerable engineering effort has been spent to catalog admin-
istrative operations and to collect them into the System Management Interface
Tool (SMIT). If what you need isn’t in the catalog...well, don’t you worry your
pretty little head about that.
Unfortunately, SMIT isn’t AIX’s only added layer of indirection. SMIT operations
map to shell commands, so every SMIT operation requires a dedicated command
that implements it in one step. Hence, the rich profusion of command families
(such as crfs/chfs/rmfs) that implement predefined recipes. These commands
add complexity and overhead without creating much value; other UNIX systems
do just fine without them.
Because administrative operations are mediated through software, AIX sees no
need to store information in text files. Instead, it’s squirreled away in a variety of
binary formats and logs, most notably the Object Data Manager. Sysadmins can
use generic ODM commands to inspect and modify this data, but that’s some-
thing of a black art, and it’s generally discouraged. Overall, the ODM is a dark and
mysterious continent with many backwaters, much like the Windows registry.
If one persists in cutting away at AIX’s carapace, one does eventually discover a
sad little UNIX homunculus lying contorted therein. But it’s not a healthy crea-
ture; it’s wrinkled with age, its skin pale from lack of exposure to the outside world
and to the last few decades of UNIX advancements. Clearly, IBM considers the
real action to be somewhere other than the UNIX mainstream.