It has happened. The UM Digital Library created and maintained by the former Library Systems Office is no longer available. Thanks to Ernest Shaw and Phil Redmon, redirects will take users to new sites. Thank you, Ernest and Phil!
Try these old links out to see how the redirects work. (You may get a page that indicates the link is broken. Wait a few moments.)
Sanborn maps: http://digital.library.umsystem.edu/cgi/i/image/image-idx?page=index;c=umcscsanic
MU college and department histories: http://digital.library.umsystem.edu/cgi/t/text/text-idx?page=home;c=sch