SUBJECT: SciNet span and AppleTalk support on the Mac

The LanC NuBus implementation on the Macintosh supports using the LanC board for running the AppleTalk (EtherTalk) protocol.

When using the LanC board, the AppleTalk performance is lower than the performance of the AppleTalk on-top-of the newer Macintosh (Quadra and Power Macs) built-in Ethernet port. We, therefore, recommend to use this option only when the Macintosh does not have a built-in Ethernet option or does not have a free NuBus slot for a standard Ethernet board. As an example: Mac IIci has only three NuBus slots that might be occupied by Video, SFL-or any other NuBus board, and Ethernet. To be able to install SciNet (PTOP) on this Mac without losing EtherTalk communications we must support AppleTalk on-top-of the LanC board. Please note that any standard NuBus Ethernet board performance is lower then the build-in port that is connected directly on the Mac internal "local bus".

Additional point for using the Build-in port for AppleTalk:
The option to run AppleTalk and SciNet on different ports allows us to create powerful and "healthy" network by supporting the two protocols on two different network segments. This way the high performance SciNet communication does not slow down the Macs AppleTalk communications (as happens with other Macintosh communications accelerator like RunShare & FileBlaster).

Please note that SciNet always runs on the LanC board independently from the selection of the board that runs AppleTalk.