I stumbled upon two copies of Apple’s iMac setup guides recently and found them pretty interesting. The guide on top is for the Rev C tray-loading model, circa January 1999, and the bottom is for a slot-loading model, circa October 1999.
The 3-page guides cover the same six steps for iMacs that are a generation apart. On first glance they look nearly the same, sporting six circular steps with color images inside. The biggest difference is the lack of text in the later guide. If you look closely you’ll notice that the computers in each image are different as well. The colors and the angles in the images are nearly the same but the details differ.
While these two iMacs share the same shape and industrial design there are differences that these guides illustrate well. In most steps you can see that the slot-loading iMac has more transparency toward the back of the case and shows more of the curved frame than the Rev C iMac, which is obscured by metal RF shielding. In steps three and five you can see that the Rev C iMac has a port door but the slot-loading model doesn’t. Step six makes the changes in the CD-ROM drive and the shape of the speakers obvious.
The colors are nearly the same except for step six which repeats grape for the Rev C model. The Rev C iMac and slot-loading iMac came in the same colors (the shades were a bit different) but the slot-loading model added an additional grey finish called Graphite.
The slot-loading iMac is an evolution of the original iMac, providing faster processors, larger hard drives, faster connectivity for external devices (Firewire), and wireless networking