Multiple Display Spanning With the iMac G5

Dan Frakes, at the Macworld Editors’ Notes Weblog:

Although many people assume that Apple’s consumer-level computers don’t support screen spanning because they use lower-end video cards or because of some other type of hardware limitation, that’s not really it — the video cards found in all of Apple’s latest consumer models fully support this feature. The real reason is that Apple has disabled extended desktop mode in Open Firmware. If you don’t know what Open Firmware is, don’t worry; the key here is that if this feature can be disabled in Open Firmware, it can also be enabled in the same way.

In other words, Apple cripples its “consumer” machines such as the iBook and iMac such that their video output to a second display is limited to mirroring, rather than spanning. An Open Firmware hack — unsupported, of course — is all it takes to enable the feature.

★ Thursday, 14 October 2004