the 'Classic' environment is not installed as a default, I
think, but should be on your Install disk (I have Tiger,
it was on DVD2). Alternately, you copy an old
System folder you have (must be 9.2 or later) onto
your hard drive, and OS X should find it, update it
automatically, and boot from it by trying to run a
System 9 program (this is how it worked for me).
I had problems with a REALLY slow start up (maybe
4 to 5 minutes, with 'Connection to Server failed'
messages by the dozen) but followed another link on
here, and in half an hour, I had cleaned up all old
references to my old hard drive (this includes, for
example, turning off in the Apple Menu options the
'last used' lists), and am getting a start up
time of about 15 seconds, even with Extensions on!!!
This has been my solution to the crappy, basic printer
driver Epson supplies for my old (but still amazingly
good) Stylus 740 printer - from OS X, you get NO
options, so I fire up OS 9.2.2, & it works like a dream.
Apart from that (even including that, I suppose!!)
Mac OS X 10.4.2 Tiger kicks ass!!!!