create_disk.sh: add comment re. s390x partition table
It came up in conversation with and that the partition
table we have here for s390x is actually transformed by coreos-installer
at install-time.
Let's add a comment to keep that in mind here.
@@ -142,6 +142,10 @@ case "$arch" in
sgdisk -p "$disk"
;;
s390x)
+ # NB: in the bare metal case when targeting ECKD DASD disks, this
+ # partition table is not what actually gets written to disk in the end:
+ # coreos-installer has code which transforms it into a DASD-compatible
+ # partition table and copies each partition individually bitwise.
sgdisk -Z $disk \
-U "${uninitialized_gpt_uuid}" \
-n ${BOOTPN}:0:+384M -c ${BOOTPN}:boot \
