Mounting system to r/w via ADB on COBY MID-7015?

I am a semi-linux n00b, so bare with me.

When mounting the various partitions on a new device, how can you figure out some of the locations for the syntax.

On a DroidX we can mount the system partition with this code:

Code:

mount -o rw,remount -t ext3 /dev/block/mmcblk1p21 /system 

How would I do this on a new device, say the MID-7015, how would I find the /dev/block/mmcblk1p21 that is applicable to the MID-7015. I am assuming you can see it with some terminal command, but alas my n00bness gets me.

Any help or pointers to where to read would be great

I am guessing I can just do a mount, and it will list the current?