When I booted raspbian on raspberry pi, the name of partition is
/dev/mmcblk0
But when I connect sd card via USB reader on Ubuntu 16.04, it shows a different name as
/dev/sdc
These sd cards are same. So what happened here?
And also does this matter when I backup and separate as two partitions with the different name by using
dd and fdisk commend ?
You mount your SD Card on different computer. All what you describe is as expected. It depends on how the SD Card is connected to the computer [1]. On your Ubuntu it is connected with an USB card reader. With this it enumerates device names just as they are connected beginning with /dev/sda, e.g. for your mounted hard disk, /dev/sdb for your CD drive and /dev/sdc for your SD Card because it was connected at last. On your raspberry pi it is connected into its slot. For this there is used a special device naming /dev/mmcblk0. For details look at the reference.
references:
[1] https://www.tldp.org/HOWTO/Partition-Mass-Storage-Definitions-Naming-HOWTO/x99.html
