<p>What's the difference and are they "Enginnering" careers or plain computer science?</p>
<p>Software developer and software engineer are basically interchangeable. I consider them engineering, and I consider "plain" computer science to be a science/engineering hybrid, but I believe that's being debated in another thread. Systems engineering is a different subject. I remember that there was a thread a while back discussing it, and you might want to do a search.</p>