OpenTransport
From Free net encyclopedia
OpenTransport was the name given by Apple Computer to their implementation of the Unix-originated System V STREAMS. OpenTransport included STREAMS-based code for handling TCP/IP and serial devices, but Apple added their own implementation of their former commonly used protocol, AppleTalk. OpenTransport also included libraries for handling various GUI tasks, and loading and unloading the various libraries on the Mac OS, which did not handle such tasks at that time.
OpenTransport was generally successful, and offered enormous speed improvements over Apple's existing TCP/IP implementation, MacTCP. Developers also liked it because it was flexible in the way it allowed protocols to be "stacked" to apply filters and other such duties.
It was introduced with System 7.5.2 which was released only with the then-new PCI based Power Macs. OpenTransport was mandatory on PCI-based Macs but a utility called Network Software Selector was released to allow switching between OpenTransport and old-style networking on older machines which supported both. OpenTransport was later abandoned during the move to Mac OS X, which uses the far more common Berkeley sockets networking system, although it is still present and usable in a limited form by older applications in the Classic environment. At the time this abandonment caused serious consternation among programmers, but this has generally disappeared since.