(Yes, in SysV the file has to be changed every year again. And SGI shows no inclination to change.)

Actually, I think SVR4 includes the Olson code, although I don't think all SVR4.0 systems supply the Olson files. However, I infer from one of Eric Raymond's lists of SVR4 bugs that SVR4.2 does supply the Olson files *and* uses Olson-style timezone specifications (":" followed by the time zone file name) by default. (The bug was that SVR4.0 binaries allegedly don't work with SVR4.2 time zone names, an example of which was given as "US/Eastern" or something such as that; that seems a *tad* bizarre, as if SVR4.0 has the Olson code, SVR4.0 statically-linked binaries should be able to handle Olson-style names, and SVR4.0 dynamically-linked binaries should use SVR4.2 shared libraries and should thus also be able to handle them. Perhaps the bug was that SVR3.x binaries don't handle Olson-style names.) SVR4 uses "/etc/TIMEZONE", but you can set TZ to ":MET" and you shouldn't have to change it every year. (Also, SVR4 should also support POSIX-style TZ settings, which should allow you to put in a value that doesn't require periodic updates *if* your locale's DST rules are sufficiently "regular" that they can be encoded in the TZ setting. I don't know which SVR3.x systems, if any, supported that.) If, as, and when IRIX goes to an SVR4 base, they should probably pick up the Olson code with it.