There are two different times that you can partition: prior to or
during the installation of Debian. If your computer will be solely
dedicated to Debian you should partition during installation as
described in section 3.5 on page [*]. If you have a machine with
more than one operating system on it, you should generally let the
other operating system create its own partitions.
The following sections contain information regarding partitioning in
your native operating system prior to Debian installation. Note that
you’ll have to map between how the other operating system names
partitions and how Linux names partitions; see Table 2.1 on page
[*].