Smalltalker from JP Morgan talks about the daily build process. Man, these guys have a monster image
Developers always start with a fresh image each day. They then ensure that all of their code loads into that fresh image. They don’t like saving images, because it leads to working on older snapshots. The build process they have takes 40 minutes, but it ensures that all developers are always working on an image that can be reproduced from scratch. A saved image cannot necessarily be reproduced.