Background
The iMac G3 was released by Apple in August 1998 under the name “iMac.” The G3 suffix was only added later when Apple released the iMac G4. Regardless, the iMac G3 is an all-in-one computer with a 15-inch screen and a gumdrop-shaped plastic case. Under the screen, the computer has two speakers and an optical drive. Apple initially released the computer in a translucent blue plastic, but they later came out with designs in red, green, orange, purple, gray, white, and some unique patterns.
In 1999, Apple released an updated version of the iMac G3 with a slot-loading optical drive. Although the iMac G3 received incremental updates until it was discontinued in March 2003, all the machines use a standard 3.5-inch hard drive for storage and two slots for memory. Thus, these parts are easy to replace if they break.
Identification
You can identify the iMac G3 by its unique colors and shape, but you can also find the serial number for your machine on the bottom of the device. The original models (with model number M4984) have a tray-loading optical drive below the screen that has a rectangular front. The new models (with model number M5521) have a rounded front panel on the optical drive. They also have two USB 1.1 ports, which were quite new at the time.
Additional Information
iMac (first model) on Apple-History