Developer Documentation
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Compatibility Issues

While the iMac computer has many new features, there should be no compatibility problems with applications that operate correctly with earlier Macintosh models. Compatibility issues for expansion and peripheral devices are listed here.

System Software

The iMac computer has newly designed system software that provides Open Firmware booting and Mac OS ROM in RAM. The system software is described in Chapter 5. For software compatibility information, see Compatibility .

Main RAM Expansion Modules

For expansion of main RAM, the iMac computer uses standard SO-DIMMs that contain SDRAM devices. These are similar to the SO-DIMMs used in the Macintosh G3 PowerBook Series. For more information, see Main RAM Expansion .

The main RAM DIMMs in the iMac must be SO-DIMMs that use SDRAM devices. SO-DIMMs that use EDO or SGRAM devices will not work.

Video RAM Expansion Modules

For expansion of video RAM, the iMac computer accepts one standard SO-DIMM that contains SGRAM devices. This is the same as the video expansion SO-DIMMs used in the the Power Macintosh G3 computers. For more information, see Video RAM Expansion .

The video RAM DIMMs in the iMac must be SO-DIMMs that use SGRAM devices. SO-DIMMs that use EDO or SDRAM devices will not work.

USB Ports and Devices

The USB ports take the place of the ADB and serial I/O ports found on earlier Macintosh computers. Software shims have been added to allow existing applications designed to work with ADB mice and keyboards to work with the equivalent USB devices. See USB Compatibility Issues .


© 1998 Apple Computer, Inc.