it is possible to display up to 256 colors or more per screen. With clever programming, it is possible to make the IIGS display as many as 3,200 colors at once. Audio is generated by a built-in Ensoniq 5503 digital synthesizer chip, which has its own dedicated RAM and 32 channels of sound. These channels can be paired to produce 15 voices in stereo. The IIGS supports both 5.25-inch and 3.5-inch floppy disks and has seven general-purpose expansion slots compatible with those on the Apple II, II+, and IIe. It also has a memory expansion slot for up 8 MB of RAM. The IIGS has ports for external floppy disk drives, two serial ports for devices such as printers and modems (which can also be used to connect to a LocalTalk network), an Apple Desktop Bus port to connect the keyboard and mouse, and composite and RGB video ports. A real-time clock is maintained by a built-in battery (a non-replaceable 3.6-volt lithium battery; removable in a later-revision motherboard). The IIGS also supports booting from an AppleShare server, via the AppleTalk protocol, over LocalTalk cabling. This was over a decade before NetBoot offered the same capability to computers running Mac OS 8 and beyond. Graphics In addition to supporting all graphics modes of previous Apple II models (40 and 80 columns text, Low and Double-Low, High and Double-High resolution) the Apple IIGS's Video Graphics Chip (VGC) introduced a new graphic mode called "Super-High Resolution". This new mode offers an increased screen resolution and a vastly wider color palette, with none of the limitations of earlier Apple II graphic modes (such as color bleeding and fringing). Super-High-Resolution supports 200 lines, in either 320 or 640 pixels horizontally. Both modes use a 12-bit palette for a total of 4,096 possible colors, with up to 256 colors (or more) on screen, though not all colors can appear onscreen at the same time. Usage of Super-High-Resolution mode may include: 320×200 pixels with a single palette of 16 colors. 320×200 pixels with up to 16 palettes of 16 colors. In this mode, the VGC holds 16 separate palettes of 16 colors in its own memory. Each of the 200 scan lines can be assigned any one of these palettes, allowing for up to 256 colors on the screen at once. 320×200 pixels with up to 200 palettes of 16 colors. In this mode, the CPU assists