This article is from the CD-Recordable FAQ, by Andy McFadden (firstname.lastname@example.org) with numerous contributions by others.
Small quantities of 90-minute and 99-minute blanks have appeared, but since
their introduction in late 2000 they haven't become as commonplace as other
lengths. Indications are that many recorders and some software don't
really work with the longer discs.
The discs have capacity of roughly 791MB (90 min) and 870MB (99 min).
However, all the capacity in the world won't help you if you can't
read the disc after you write it. If you're interested in larger but
incompatible discs, your best bet is probably DVD-R. Other alternatives,
such as DD-R/DD-RW (section (2-37)), ML (section (2-39)), and GigaRec
(section (2-46)) never really took off.
CD time stamps are two digits (binary coded decimal, in case you were
wondering), so exceeding 99 minutes isn't possible. You could, in theory,
declare there to be 99 seconds in a minute and 99 sectors per second, but
that would break just about everything that tried to read one. The limits
of the specifications are being pushed at 80 minutes and even harder at 90,
so don't expect much more out of CD-R. Some knowledgeable individuals have
stated that the longest possible CD-R is 79 minutes, 59 seconds, 74 blocks
long, because of the way that the last possible start time of the lead-out
is encoded, but you can use "overburning" (discussed in the next section)
to write past that point. (Experiments suggest that the actual limit is
88 minutes; either way, you're pretty far from 99.)
See http://www.mmore.com/download/Technical_write-up-MMORE_90_min.pdf for
a tutorial on burning 90-minute discs with Nero. In short: make sure your
drive supports overburning, set "Enable overburn" in the "Expert features"
tab of the preferences, ignore the warnings, and cross your fingers.
Always verify the disc afterward.