Happy 19th birthday, Cocoa!

On October 19th, 1994 NeXT Computer, Inc. (later NeXT Software, Inc.) published a specification for OpenStep, a cross-platform interface for application programming, based on their existing Objective-C frameworks and the Display PostScript graphics system.

A little bit of history

First there came message-passing object oriented programming, in the form of Smalltalk. Well, not first, I mean first there was Simula 67, and there were even things before that but every story has to start somewhere. In 1983 Brad Cox added Smalltalk messaging to the C language to create the Object-Oriented pre-compiler. In his work with Tom Love at Productivity Products International, this eventually became Objective-C.

Object-Oriented Programming: an Evolutionary Approach

If PPI (later Stepstone) had any larger customers than NeXT, they had none that would have a bigger impact on the software industry. In 1988 NeXT released the first version of their UNIX platform, NEXTSTEP. Its application programming interface combined the “application kit” of Objective-C objects representing windows, menus, and views with Adobe’s Display PostScript to provide a high-fidelity (I mean, if you like grey, I suppose) WYSIWYG app environment.

NeXTSTEP Programming Step One: Object-Oriented Applications

N.B.: my reason for picking the Garfinkel and Mahoney book will become clear later. It happens to be the book I learned to make apps from, too.

Certain limitations in the NEXTSTEP APIs became clear. I will not exhaustively list them nor attempt to put them into any sort of priority, suffice it to say that significant changes became necessary. When the Enterprise Objects Framework came along, NeXT also introduced the Foundation Kit, a “small set of base utility classes” designed to promote common conventions, portability and enhanced localisation through Unicode support. Hitherto, applications had used C strings and arrays.

It was time to let app developers make use of the Foundation Kit. For this (and undoubtedly other reasons), the application kit was rereleased as the App Kit, documented in the specification we see above.

The release of OpenStep

OpenStep was not merely an excuse to do application kit properly, it was also part of NeXT’s new strategy to license its software and tools to other platform vendors rather than limiting it to the few tens of thousands of its own customers. Based on the portable Foundation Kit, NeXT made OpenStep for its own platform (now called OPENSTEP) and for Windows NT, under the name OpenStep Enterprise. Sun Microsystems licensed it for SPARC Solaris, too.

What happened, um, NeXT

The first thing to notice about the next release of OpenStep is that book cover designers seem to have discovered acid circa 1997.

Rhapsody Developer's Guide

Everyone’s probably aware of NeXT’s inverse takeover of Apple at the end of 1996. The first version of OpenStep to be released by Apple was Rhapsody, a developer preview of their next-generation operating system. This was eventually turned into a product: Mac OS X Server 1.0. Apple actually also released another OpenStep product: a y2k-compliant patch to NeXT’s platform in late 1999.

It’s kindof tempting to tell the rest of the story as if the end was clear, but at the time it really wasn’t. With Rhapsody itself it wasn’t clear whether Apple would promote Objective-C for OpenStep (now called “Yellow Box”) applications, or whether they would favour Yellow Box for Java. The “Blue Box” environment for running Mac apps was just a virtual machine with an older version of the Macintosh system installed, there wasn’t a way to port Mac software natively to Rhapsody. It wasn’t even clear whether (or if so, when) the OpenStep software would become a consumer platform, or whether it was destined to be a server for traditional Mac workgroups.

That would come later, with Mac OS X, when the Carbon API was introduced. Between Rhapsody and Mac OS X, Apple introduced this transition framework so that “Classic” software could be ported to the new platform. They also dropped one third of the OpenStep-specified libraries from the system, as Adobe’s Display PostScript was replaced with Quartz and Core Graphics. Again, reasons are many and complicated, though I’m sure someone noticed that if they released Mac OS X with the DPS software then their bill for Adobe licences would increase by a factor of about 1,000. The coloured box naming scheme was dropped as Apple re-used the name of their stagecast creator software: Cocoa.

So it pretty much seemed at the time like Apple were happy to release everything they had: UNIX, Classic Mac, Carbon, Cocoa-ObjC and Cocoa-Java. Throw all of that at the wall and some of it was bound to stick.

Building Cocoa Applications

Over time, some parts indeed stuck while others slid off to make some sort of yucky mess at the bottom of the wall (you know, it is possible to take an analogy too far). Casualties included Cocoa-Java, the Classic runtime and the Carbon APIs. We end in a situation where the current Mac platform (and, by slight extension, iOS) is a direct, and very close, descendent of the OpenStep platform specified on this day in 1994.

Happy birthday, Cocoa!

About Graham

I make it faster and easier for you to create high-quality code.
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