In 1999, Apple released a humble product called Mac OS X (pronounced “ten”) Server 1.0. In look and feel, the operating system was very similar to Mac OS 8 (and 9), but, beneath the interface, the system contained some drastic changes that would eventually revolutionize the entire Macintosh software line. It eschewed the classic Mac OS nanokernal for the NEXTSTEP hybrid kernel, and it contained a hybrid of classic Macintosh features and NEXTSTEP features – even requiring an emulation layer to run classic Mac OS applications. This Mac OS was unlike anything that had come before it. In fact, it was really Mac OS in name only.

A Little Background

In 1986, two years after the introduction of the Macintosh and the Mac OS, Steve Jobs found himself ousted from the company he helped create. Ever the entrepeneur, he quickly launched into two new ventures – one was an unwanted animation studio that would become Pixar, and the other was a new computer company called NeXT.

NeXT computers were technically advanced for their time. They were released in 1990 with 25MHz processors, 8 MB RAM, an ethernet port, 256 MB storage, and a 1120×832 display. In contrast, typical machines of the time would have had 16MHz processors, 640 kb RAM, no networking, 10-40 MB storage, and 640×350 displays. NeXT Computer is considered a pioneer in bringing networking to desktop computers. The first email programs and web browsers were developed for NeXT. Unfortunately, the NeXT hardware was doomed to failure (mainly due to prohibitively high costs), but the operating system would live on.

NEXTSTEP was released in the days of Windows 3.1 and Mac OS 7, and it stood out from its competition both visually and in capabilities.



Mac OS 7, Windows 3.1, and NEXTSTEP. These screenshots are all courtesy of Wikipedia.

NEXTSTEP was based on the Mach kernel and BSD. It featured object-oriented programming based on the Objective-C language. It was meant to be viewed on higher-resolution displays, and it included many software tools for networking and collaboration. Additionally, NEXTSTEP was the first general operating system to handle color standards, advanced sound processing, modern typography, and internationalization. It’s interface featured real-time scrolling and window dragging as well as window notifications and transparency. Again, this was all in the early 90’s, well before the world would be captivated by Windows 95.

NEXTSTEP faded into obscurity after the mass adoption of Windows 95, but it would find a strange rebirth in 1996 when it was acquired by Apple, and Steve Jobs returned to the company that had rejected him ten years prior.

Reinventing the Mac OS

When Steve Jobs came back to Apple through the NEXT acquisition, Apple had already put massive efforts into overhauling the Mac OS through the Copland and Taligent projects (though some Copland features were eventually incorporated into OS X). Both of these systems were laid to rest in the late nineties in favor of Rhapsody, an operating system based primarily on the OPENSTEP (neé NEXTSTEP) operating system. Rhapsody eventually became Mac OS X Server 1.0 which would lead to the public beta of Mac OS X.


OPENSTEP and Rhapsody (both courtesy GUIdebook) side by side

Though called Mac OS, system 10 shared little in common with the previous Mac operating systems outside some superficial interface elements. Like NEXTSTEP, Mac OS X is based on the Mach kernel and BSD Unix. They are both object-oriented environments based on the Objective-C programming language. Both feature a dock, system services, managed memory, and preemptive multitasking. In fact, if you crack open the UI of most Mac OS X applications, you will find files with the extension “.nib” contained within. NIB is short for NeXT Interface Builder.

Like Mac OS X Server 1.0 and the Rhapsody developer builds, Mac OS X is incapable of natively running applications written for previous versions of the Mac OS. These applications were relegated to a “blue box” called Classic, and they could not take advantage of Mac OS X’s more advanced features. The Classic layer, effectively the final vestiges of the original Mac OS, lost support with the recent Intel-transition of Macintosh computers, placing the final nails in the coffin of the system that served Apple since 1984.


System 1.1 (from GUIdebook) next to Mac OS X 10.5 Leopard (from Apple)

As John Siracusa wrote last year (on the fifth anniversary of Mac OS X), “The Mac is dead. Long live the Mac.” OS X is Mac OS in name only. Truth be told, Mac OS X is the never-released NEXTSTEP 5, for the system shares much more in common with that legacy than with the Mac OS legacy. Apple took a daring move with Mac OS X in that they completely pulled the rug out from under their current OS foundation and replaced it with something entirely new – a feat that other OS vendors have been reluctant to attempt.

As Mac OS X becomes a more mature product, it resembles NEXTSTEP more and more while retaining the style and simplicity Mac users have come to expect. NEXTSTEP and the classic Mac OS were products doomed to failure – the former for being too far ahead of the times and the latter for being to far behind – but Apple has created a powerful and stable operating environment from the ashes of both, similar to each but ultimately original and innovative.