Missing mail archives

I just realized that many older mailing list messages do not appear to be 
archived on the IETF. In particular, I found very little before July, 1998.

I’d particularly like to find the MMUSIC and AVT archives. 

I have the vague feeling that a lot of other stuff is missing prior to summer 
1998 from other groups, but I wasn’t paying that much attention to them at the 
time.

Do we have this stuff hiding somewhere?