Thanks.  I'm not sure I agree as to compatibility issues, but that is
probably because I find that certain software vendors (IBM) often make
poor design choices and then we are stuck with them "forever" because
of having to be compatible.
 
DEC's TOPS-20 operating system had a neat feature that allowed a file to
have a version number.  One could reference a file without a version number
and always get the most recent (highest number) version.  Opening for
output always created a new version unless the version was specifically
requested.  This file system allowed a subroutine to be referenced either
generically, or by specific version.  Combining this concept with management
practice that maintained incompatible versions, the compatibility issues
would be less severe, allowing (hopefully) for greater progress in software
sophistication.  Too bad IBM did not adopt something like this.
 
The multiple X-To has been seen only on SOME mail, less than half.  My
ListServ is on 1.5b I think (it says it is).
 
I still have not gotten hold of the person in the graduate admissions
office here who handles foreign student admission.  I have gone ahead
and sent to you by snail mail (postal delivery) the Graduate Programs
Catalog and the Catalog of Course for University of Illinois/UC.