I had the pleasure to talk for an hour to Jan Baan, the founder of ERP pioneer Baan and now business process management firm Cordys. One of his major themes was the value of being able to look back to the ERP days and benefit from the wisdom of a cadre of fellow (and maybe mellow) executives from the old company. Baan is a true software veteran, only half a year short of the age when The Beatles suggested he might be "doing the garden, digging the weeds, who could ask for more". But he is hardly alone in running a business software concern as the whole business software sector has grown up and it is common -- indeed typical -- to be CEO in the sixth or seventh decade of life.

Using the Software Top 100 as source material, 55 or 56 would appear be the mean average age at which the running of a top 10 software concern can be yours. Henning Kagermann is 62, Steve Ballmer is 53 and Oracle's Larry Ellison was 65 yesterday, although his youthful appearance suggests either a picture in the attic or some M&A with a guy called Faust. Recent arrivals at the top of the software CEO tree Enrique Salem of Symantec (43) and Adobe's Shantanu Sarayem (45) bring down the average considerably.

The rise of client/server software brought in an age of the sickeningly youthful tech billionaire but these builders of what Robert X. Cringely called "accidental empires" are all grown up now. They haven't lost their cachet, however and like the geriatrics that fill stadia around the world, they've just proven that software, like rock and roll, is no longer a young man's game.