It was written....
Good question! I'm a little curious about that
too. I also remember
(very
vaguely) seeing some 24" rack panels and such in some catalog, ages ago,
but I don't recall ever running into any hardware that used it.
24" racks
are just as common as 19" racks, depending on your industry. 19"
racks are the defacto standard in the computer industry. 24" racks are still
today the defacto standard in the telco industry. There are some few
occasions where 24" racks are used in the computer industry and 19" in the
telco industry... but not really common.
Walk in to any SWB, Pacbell, etc. phone center and you'll see mostly 24"
racks for telco gear/switches.
Jay West