my guess, each strip has an id to uniquely identify each one. For simplicity, say the id is just a number. When you click next, it just bumps to the next one in line..i.e. 1,2,3,4, etc...
so...maybe it's "random order", as opposed to just "random".
i.e. a random order of numbers from 1 to 5 might be: 5,1,2,3,4.
..then when you hit random, it just bumps you to the next one in this predefined random order.
When I hit random on my ipod and move the next song, I think it really is random because sometimes I get the same song again.
...computers inherently cannot create a true random number anyway.
For example, in this C snippet, I use the the current time to generate a seed value, and then this is used as a basis for generating a random number between 0 and maxNum.
randNum1 = (lrand48() % maxNum)http://linux.about.com/library/cmd/blcmdl3_srand48.htm