Operating Systems

In 1984, Apple Computer introduced the Apple Macintosh personal computer.  The first version was the Macintosh 128K model which came bundled with the Mac OS operating system then known as the “System Software”.  The Mac is often credited with popularizing the graphical user interface (GUI).

The Mac OS has been pre-installed on almost every Macintosh computer ever sold.  The operating system is also sold separately from the computer just as with Microsoft Windows.  The original Mac OS was heavily based on the Lisa OS previously released by Apple for the Lisa computer in 1983.  It also used concepts from other operating systems previewed by Apple executives.

In 1984, Apple partnered with Microsoft in an agreement that would have Microsoft creating versions of Word and Excel for the Mac OS.  For the majority of the 1980’s, the Mac OS lacked a large amount of compatible software, however, the introduction of System 7 saw more software becoming available for the platform.

System 6 was the first major revision of the operating system, although the Mac OS kernel was kept the same from the System 7 revision until Mac OS 9.

The Macintosh project started in early 1979 with Jeff Raskin who envisioned an easy-to-use low-cost computer for the average consumer.  In September of ’79, Raskin was given permission to start hiring for the project.

In January of 1981, Steve Jobs completely took over the Macintosh project.  Jobs and a number of Apple engineers visited Xerox PARC in December of 1979 which was three months after the Lisa and Macintosh project had begun.

After hearing about the pioneering GUI technology being developed at Xerox PARC from former employees like Raskin, Jobs negotiated a visit to see the Xerox Alto computer and Smalltalk development tools in exchange for stock options.  This was probably one of the best business moves Jobs had ever made.

The final Lisa and Macintosh operating systems used concepts from the Xerox Alto, but many elements of the GUI were creating by Apple including a menu bar and pop-up menus.  Specifically, the click and drag concept was developed by Jeff Raskin.

Unlike the IBM PC which used 8 KB of system ROM for power-on self test and basic input/output chores, the Mac ROM was significantly larger at 64 KB and held key OS code.  Andy Hertzfeld was responsible for most of the original coding.  He was able to conserve some of the ROM space by interweaving some of the assembly language code.

In addition to coding the ROM, he also coded the kernel, the Macintosh Toolbox, and some of the desktop accessories as well.  The icons of the operating system which represented folders and application software were designed by Susan Kare who later designed the icons for Microsoft Windows 3.0.

Apple was very strong in advertising this new machine.  After it was created, they actually bought out all thirty-nine pages of advertisement space in Newsweek Magazine’s November/December, 1984 edition.  It worked incredibly well and the investment paid off as Macs began flying off the shelves.

The first version of Mac OS along with subsequent updates were different from other operating systems in that this OS didn’t use command line interface but rather user friendly interface. Many people think that Windows was the first to employ GUI, but Mac had them beat.

Updates to the OS mostly focused on changes to the “finder” which is an application for file management which also displays the desktop.  Prior to version 5, the finder could only run one application at a time.  When version 5 was released, it contained multi-finder which could run several applications at once.

Time was given to background applications only when the foreground running applications gave it up in co-operative multitasking, but in fact most of them did via a clever change in the operating system’s event handling. 

System 5 also brought Color Quick Draw to the Mac II.  This significantly altered the extent and design of the underlying graphics architecture but it is a credit to Apple that most users, and perhaps more importantly existing code, were largely unaware of this.

System Software 5 was also the first MAC operating system to be given a unified system software version number as opposed to the numbers used for the system and finder files.

In 1991, System 7 was released.  It was the second major upgrade to the Mac OS adding a significant user interface overhaul, new applications, stability improvement, and many new features.

The most visible change was a new full-color user interface.  Although this feature made for a visually appealing interface, it was optional.  On machines not capable of displaying color or those with their display preferences set to monochrome, the interface defaulted back to the black and white of previous versions.  Only some interface elements were colorized:  scrollbars had a new look but push buttons remained in black and white.

The biggest feature added in system 7 included the built-in co-operative multitasking.  In system 6, this function was optional through the multi finder.  System 7 also introduced aliases which are similar to shortcuts that were introduced in later versions of Windows. 

System extensions were enhanced by being moved to their own subfolder.  A subfolder in the system folder was also created for the control panels.  A smaller update - dubbed system 7.5 - included the extensions manager, a previously third party program which simplified the process of enabling and disabling extensions.

System 7 moved the Mac to true 32-bit memory addressing necessary for the every-increasing amounts of RAM available.  Earlier systems used the lower 24 bits for addressing and the upper 8 bits for flags.  This was an effective solution for earlier Mac models with very limited amounts of RAM, but it became a liability later.  Virtual memory support was also added as a separate, optional feature.

The Apple menu, home only to desk accessories in system 6 was made more general purpose:  the user could now make often-used folders and applications - or anything else they desired - appear in the menu by placing aliases to them in an “Apple Menu Items” subfolder of the system folder.

The trash folder, under system 6 and earlier, would empty itself automatically when shutting down the computer or, if multi-finder were not running, when launching an application.  System 7 re-implemented the trash as a special hidden folder allowing files to remain in it across reboots until the user deliberately chose the “Empty Trash” command.

There were some other “high level” additions in system 7.  Many people felt that Apple dropped the ball on some of these additions and accused the company of not fully thinking through these updates.  Microsoft was accused of the same thing with earlier versions of Windows as well.

One of the most confusing aspects of the Mac OS was the reliance on countless System Enablers to support new hardware which would prove to plague the Mac OS all the way to version 8 after which iMac introduced its “New World” architecture.  Although the iMac itself requires a system enabler with OS 8 as other Macs released at that time, Macs released after the iMac do not require a system enabler.

Another problem encountered was that various system update extensions with inconsistent version numbering schemes.  Overall stability and performance of the Mac OS gradually worsened during this time which introduced Power PC support and 68K emulation.

When version OS 7.6 was released, the stability of the operating system was much better.  People began to fully embrace the Mac OS and their legitimacy returned as a popular operating system.

System 7 also saw the introduction of an interactive help application, and the addition of “Stickies” which were basically virtual Post-It notes.  Many Mac users still have OS 7 on their Apples.

Two other versions would follow in OS 8 and OS 9 each improving on the previous version.  Apple continued to develop updates to their operating system making it more stable and capable of more tasks working efficiently to bring Mac into the 21st century.

The most recent version and one that is used on new systems today is Mac OS X.  This version provides a stable operating environment for the Mac PC and offers more flexibility than other systems.  The graphics are updated with lots of color and a flashier look.