Bits and pieces of longstanding Mac APIs are finding their way out of OS X and into code repositories of history. One of the latest, with the introduction of OS X Mavericks, is Open Transport.
Developer Brent Simmons pointed out the loss in a post on his Inessential blog. Open Transport was included in OS X through version 10.8.
I admit that I was astounded that Open Transport still remained in the OS. It's been around since System 7 in the classic Mac days.
Newcomers to Macs or Windows systems have no clue about how networking was implemented back in the days. Nowadays, we have easy switching between various wireless and wired networking hardware and protocols and we take this for granted. It was so much harder back then, for users, developers and networking vendors.
For example, Open Transport let Mac users change networks or even settings without restarting the computer. Restarting, that's right. The user interface let users store various configurations and switch between them. Magic.
Here's a bit of the flavor of those times. It's from the MacInTouch column by Ric Ford in the April 15, 1996 issue of MacWEEK, titled "Open Transport is friendly, but splits Mac family:"
Apple does not support classic networking on PCI Power Macs, and it is not clear if some variation on the original MacTCP work-around for these models is still viable. Apple's Network Software Selector, the utility for switching between classic and Open Transport networking, is a little strange. It switches to Open Transport networking by disabling the MacTCP and Network control panels and making them invisible. The files remain in the Control Panels folder, however, for switching back. (Apple puts Network Software Selector in an Apple Extras folder instead of more conveniently in Apple Menu Items or Control Panels.)
In addition, Simmons said a number of other familiar frameworks are being depreciated.
Newly-deprecated: InstantMessage.framework, Quicktime.framework, QTKit.framework. (Superseded by Social.framework and AVKit and AVFoundation.)