What's the difference between college-level and corporate programming?

As I explained to someone starting their first programming job, "In college, you get into trouble if you use someone else's code. At work, you get into trouble if you don't." In other words, always search for some code with a licence we can use before writing your own.

My experience of college code is that it may work but it rarely scales and performs well. For example, I downloaded a driver that set up the DMA, did the data transfer then tore down the DMA for every read and write. I changed it to set up the DMA for an open and tear it down for a close, leaving the DMA set up for the data transfers.