Wringing out the changes
By Paul Murphy, author of The Unix Guide to Defenestration
Sun sometimes makes changes to Solaris, especially stuff considered "security related," that they don't go out of their way to tell you about. For example, did you know that tftp's behavior changed quite dramatically somewhere between 2.5.1 and 2.7? I know I didn't find out until some tftp boot sensitive devices started failing and it took most of an afternoon to figure out that tftp now silently refuses to respond if asked for a file it can't access.
On the other hand, you don't have to accept some of these changes. On something like tftp, for example, you can just load the binaries from 2.5.1 and pretend you don't hear the groans from the peanut gallery.
More generally you can load and run just about anything compiled for SPARC from as far back as SunOS 4.1.3 as long as you're careful about dependencies and don't care about the security implications of your actions. Suppose for example that you suffer from a severe mental illness that makes you want to use your 1989 BRS Search license for SunOS and your 1993 copy of WABI and Microsoft office on a Solaris 9 machine. Impossible? not at all - just create a static device tree that's got the libraries you need and, as long as you don't have kernel dependencies, the executables will execute.