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