Back-up discs are to re-set to factory settings. Using CD's would take this amount of discs and was important to number them to load in sequence.
Today it's a DVD disc and only requires one and you have the option to repair the OS.
Surface Pro (2017) vs Surface Pro 4
Where HTML5 is headed next
MacBook Pro v Surface Pro 5
Synology invites you to visit them at Insomnia on 26th – 29th August. Book your tickets now and visit Synology.