I am using a Sony (sve15118fnb) laptop. Recently I installed windows 10 and decided to dual boot it with Ubuntu. The disk uses MBR partition table, so the maximum number of primary partitions allowed is 4.
The disk partitions before installing Ubuntu, the red boundary indicates what was a logical partition before installing Ubuntu:
This makes 3-primary and 1-logical partition. But while installing Ubuntu, I went with the default (primary) as the partition type for swap and root directories. And after installing Ubuntu, the disk management shows partitions like this after installing Ubuntu
This makes 5-primary!! and 1-logical partition. How is this possible?
PS: While installing Ubuntu, I didn't get any error/warning about the max number of primary partitions allowed. But every time before booting into Ubuntu this message shows up and only shows when booting to Ubuntu and not while booting to Windows: