What is macOS (Macintosh Operating System)?

macOS stands for Macintosh Operating System. Apple develops it for Macintosh computers. This system introduced a graphical interface.

Users can interact using a mouse with windows, icons, and menus. Overall, macOS revolutionized how we use computers. Its design makes tasks more intuitive and user-friendly. Consequently, it laid the groundwork for modern operating systems.

What is the macOS Operating System?

Apple aimed to make the Macintosh user-friendly. They reduced the operating system’s presence in its early years. This choice helped differentiate it from MS-DOS, which posed technical challenges.

The original macOS team included Bill Atkinson, Jef Raskin, and Andy Hertzfeld. They developed the classic version entirely in-house. The first version launched in 1984.

Over time, the system evolved, leading to nine versions released by 1999. Then, Mac OS X emerged. This version is a Unix variant and retains elements of its predecessors in the graphical interface.

Opinions vary about the original macOS development process. Historical documents link the Macintosh project to the Xerox PARC Alto project.

Additionally, initial contributions came from Ivan Sutherland’s Sketchpad and Doug Engelbart’s On-Line System, both influential in shaping ideas.

Historical

Mac OS X was not the first graphical interface. However, it succeeded due to its affordability. The Xerox Alto was priced at $32,000 back then. It was the star product of Xerox.

The Apple Lisa followed, costing $16,600 and then $10,000. Interestingly, the name “Apple” came from Steve Jobs’ daughter. Finally, System 1 was included in the first Macintosh. The price for this was $2,500.

System 1: 1984

System 1 featured a desktop computer. It included Windows, icons, a mouse, menus, and scroll bars. The Trash acted like a garbage can.

After restarting, everything in it disappeared. Since there was no virtual memory, users couldn’t run two applications at once.

Additionally, creating folders within folders was impossible. All files were saved in one location. A note in the file table allowed each file to appear in its designated folder. This helped users find files in the Finder.

Later, System 1.1 introduced a dialog box. It also added a command to clean your Mac and some speed apps.

System 2: 1985

In 1985, System 2 made notable improvements. First, it increased Finder speed by twenty percent. Then, it removed the return and close commands.

Next, users could create new folders more easily. Meanwhile, closing and desktop printer options were simplified. Items are now listed vertically, each with a small icon.

Additionally, users can drag discs or drives to the trash icon for easy removal. Overall, these updates enhanced user experience with a more efficient interface.

System 3: 1986

In System 3, Finderr is faster and improved. The old HFS has been replaced with the new Macintosh MFS.

Folders are now real, and you can create folders within folders. Zoom icons appear in the bottom right of the Dashboard. Click them to adjust folder content size.

A second click returns the window to the standard size. The trash icon clearly shows when something is placed on it. The lines on it are dotted in opposing directions.

In System 3.2, thirty bugs were fixed. Additionally, the calculator received an update. Now, the on-screen numeric keypad resembles the keyboard keypad. In System 3.3, AppleShare was added for sharing old Macintosh files.

System 4: 1987

System 4 debuted with the Macintosh SE and II. This update introduced support for multiple monitors. Additionally, System 4.1 now supports disks larger than 32 MB.

Users can switch between the standard Finder and Multiple Finder. The standard Finder supports one program, while Multiple Finder handles many programs simultaneously.

Furthermore, Finder displays the memory usage of each program. A new Control Panel is also now configurable. Finally, System 4.3 received updates to fix bugs and printer drivers. This streamlined experience enhances user productivity and system performance.

System 6: 1988

In 1988, System 6 introduced new colors. However, the Finder still lacked color despite the machine’s capabilities.

Additionally, a button was added to cancel the “Erase Disk” process. Users can now see the file version number as well.

Moreover, a notification feature was included. This alerts users via the menu bar when programs need to connect. Finally, versions 6.0.1 to 6.0.8 offered support for new models.

System 7: 1990

System 7 was a major software update for its time. It removed Finder and Multiple Finder. Instead, System 7 introduced many Finders that could perform multiple tasks.

A significant memory change occurred with the increase to 32MB. This allowed Macs to use more than 8MB of RAM, enhancing the operating system.

Additionally, networking options like AppleTalk were included. File sharing became possible through AppleShare.

QuickTime multimedia software was studied, but was offered as extra software. Furthermore, System 7 added various features for the upcoming Mac OS X.

A menu appeared at the bottom right of the Dashboard. This menu shows the list of running programs and allows easy switching.

After that, a “Help” menu was added. The “trash” changed into a real folder. Now, files could be deleted until the “Empty” option was selected.

Moreover, the drag-and-drop feature was implemented. This allowed users to move text between programs easily. In System 7, the Finder showcased colorful objects and a 3D interface.

The 7.0.1p Performa System launched alongside System 7.0.1. It fixed unique features for new users. System 7.1 made adding or removing a Fonts folder simple. Users could easily add fonts within the same system.

System 7.1.1, also known as SystemScript Pro, was offered as a system extra. It included AppleScript, QuickTime, and PowerTalk. Then, System 7.1.2 was created to support new microprocessor chips.

Next, System 7.5 integrated all Performa features. It provided much more information than the previous Apple Guide. A small bar even appeared on the boot screen.

After eleven years of development, Mac needed an entirely new operating system.

Thus, System 7.6 was the first to follow Apple’s new strategy. It received updates every six months until Rhapsody, or Mac OS X, ended. Finally, some bugs were fixed with version 7.6.1.

System 8: 1997

The Finder received a significant update. It now allows better control over multiple applications. This change boosts performance on processor-intensive computers.

Additionally, the Finder has a refreshed 3D appearance. Users can also customize its look to suit their preferences.

Web Sharing is another new feature. It enables users to host web pages directly from their computers.

Notably, HFS+ now requires more than 1 GB of free space on the hard drive. Furthermore, this was the last version supporting 68K Macs. Earlier versions were exclusively for PowerPC systems.

Version 8.5 introduced Sherlock, an advanced search tool. It searches local disks, network services, and the Internet.

In version 8.6, management features improved significantly. It also added a content option for Sherlock and introduced support for USB and FireWire.

System 9: 1999

In this version, users can add multiple accounts on a Mac. This feature allows each user to have their own settings. Additionally, AppleTalk now works over TCP/IP.

Moreover, Software Update lets users get updates over the Internet. It also informs users when new updates are available.

Versions 9.0.2 and 9.0.3 included special models. Then, 9.0.4 brought everything together. Following that, 9.1 improved stability and added menu windows. This version represents the lowest level of Classic in 10.0 and 10.1.

Furthermore, “Quicksilver” Power Mac G4s launched in the summer of 2001. They introduced version 9.2 as a preinstalled system.

Mac OS X

OpenStep is based on PowerPC. It inherits Mach’s memory and processor features.

Additionally, it uses the UNIX Protocol for device drivers. This protocol supports BSD’s network interface. Moreover, it incorporates some elements from NeXT’s interface.

Today, this operating system runs on almost all Macs. It has successfully evolved over the past ten years.

10.0 “Cheetah”: 2001

Version 10.0 launched on March 24, 2001. It included many features from the Public Beta contributors.

Moreover, it had all the features expected from a modern operating system. This ensured that programs did not interfere with each other. As a result, the processor was less likely to crash.

Device drivers were required to be installed. Additionally, Cocoa was added. This came from NeXT’s advanced OpenStep environment. However, some tasks from the original Mac system were still incomplete.

Users of OS X frequently complained about the name “Cheetah.” Many found it strange and inappropriate. The Classic environment in version 10.0 improved over the General Beta. Still, users faced compatibility issues and odd behaviors.

Furthermore, the interfaces of OS X resembled the macOS interface. Users thought they had similar features. However, they needed to adapt and learn new habits. Overall, change was necessary to move away from the old system.

10.1 “Puma”: 2001

It was released after versions 10.0 and 10.1. This update improved performance, especially on Macs with G3 processors.

Additionally, the updates included bug fixes and component enhancements. These updates are known as versions 10.1.1 through 10.1.5.

Moreover, many open-source UNIX utilities are now available. As a result, additional drivers support a wider range of devices.

10.2 “Jaguar”: 2002

On August 25, 2002, Apple released the 10.2 “Jaguar” version of its operating system. This update improved performance and featured a refined look. It also included over 150 enhancements.

Notably, it increased support for Microsoft Windows networks. Additionally, it introduced Quartz Extreme, which allowed the graphics card to handle more tasks. A new spam filter was added for better email management.

Moreover, Apple introduced the Rendezvous network system. This feature helped store Address Book contact information. iChat was also included. It offered chat support for AOL Instant Messenger.

Lastly, the update included a redesigned Finder. Now, every window supports integrated searches for more straightforward navigation.

10.3 “Panther”: 2003

MacOS Xv10.3 “Panther” launched on October 24, 2003. It brought higher performance and a revamped user interface.

This update was significant compared to the previous year’s Jaguar. However, it no longer supports older G3 models.

In Panther, Finder received an update. It features a metallic interface and speed search options.

Additionally, Exposé introduced a new way to manage windows effectively.

Another addition is Quick User Switching. This feature allows multiple users to open sessions and switch quickly between them.

Moreover, this version includes integrated fax support. FileVault offers real-time encryption for users’ private directories.

Panther also boosts system-wide speed, particularly for G5 models. Overall, Panther marked a notable upgrade in macOS history.

10.4 “Tiger”: 2005

Version 10.4, called “Tiger,” was released on April 29, 2005. It introduced over 200 new improvements. However, some older machines could not support it. Notably, Tiger required a FireWire connection for all Apple devices.

This version introduced exciting new features. For instance, Spotlight is a content and metadata search system. Additionally, Dashboard widgets allow quick access to everyday tasks and information.

QuickTime 7 debuted with H.264 support and a redesigned interface. Furthermore, Safari received updates, including better speed, security, and RSS support. Lastly, Tiger offered 64-bit memory support for new G5s, using the LP64 system.

10.5 “Leopard”: 2006

The Leopard version was released on October 26, 2007. This version is compatible with PowerPC and new Intel technology. Among the features of the latest version:

1. Time Machine: It allows you to revert to a particular version of a folder, the entire hard drive, a single file, and a roll of photos in iPhoto.
2. Mail 3: This is the third version of this email program from Apple, which now includes Notes and To-Do, as well as various Templates for sending HTML emails.
3. iChat: It allows you to chat with tabs or have animated icons; now, it has many additional functions for presenting video for video chats and sharing the desktop.
4. Dashboard: Brings a tool called Dashcode to create widgets easily. In addition, Safari has a Webclip button that allows you to take any part of a page being viewed and convert it to a Widget. Improvements have been made to accessibility features.
5. Finder: With CoverFlow, similar to iTunes, it has a function called QuickLook that allows you to open several files at the same time with different extensions, and there is no need to open the program; users can even search other network-connected Macs.
6. Dock: It looks like a glass tray that receives reflections and has stacks that let you stack a series of items, and when you click on it, it appears in a number of options.

A breakthrough in text-to-speech features with a new synthesized voice called Alex, the largest of which can speak clearly at high speeds. It also brings support for Braille displays.

10.6 “Snow Leopard”: 2009

The latest version of the Mac operating system, nicknamed Snow Leopard, was released on August 28, 2009, and is faster than its predecessors, in addition to a few new exciting features:

• The new Exposéis are integrated with the Dock.
• You can use the touch screen to add Chinese characters.
• The time zone is set automatically.
• Provides support for connecting to Microsoft Exchange 2007 servers.
• Less challenging disk space consumption and a maximum of 16 TB RAM support.

The following innovations should also be highlighted:

• Grand Central is a programming technique that allows you to use multi-core processors and optimize performance.
• QuickTime X will have optimized support for existing codecs.
• OpenCL (Open Computing Language) allows you to program applications that use the graphics processing unit for non-graphic use.

10.7 “Lion”: 2011

This release came out on July 20, 2011. It brought several enhancements to Apple’s iOS. One new feature is the launchpad. This tool lets users navigate easily between installed apps. It also makes better use of multitouch gestures.

In addition, the update removed Rosetta. As a result, PowerPC applications became incompatible.

Moreover, there were changes to the graphical user interface (GUI). For instance, auto-hiding scroll bars now appear only when in use.

Lastly, Mission Control was introduced. This feature combines Exposé, Spaces, Dashboard, and full-screen applications into one interface.

10.8 “Mountain Lion”: 2012

Mountain Lion was released on July 25, 2012. It marked the beginning of two-year updates. Game Center now includes apps like Reminders.

This app serves as a separate to-do list from iMessage and iCal. Additionally, iWork allows users to back up documents on iCloud. Overall, these features enhance user experience and productivity.

10.9 “Mavericks”: 2013

Launched on October 22, 2013, Mavericks was a free upgrade for all users working with a 64-bit Intel processor for Snow Leopard or later.

10.10 “Yosemite”: 2014

Launched on October 16, 2014, Yosemite includes many features similar to iOS 7. For example, it had a redesigned user interface with a more minimal, text-based ‘flat’ design with translucent effects and intensely saturated colors.

10.11 “El Capitan”: 2015

Launched on September 30, 2015, El Capitan enhances the Mac experience. It focuses on improving system performance.

For instance, it brings updates to Maps and Notes applications. Additionally, it features the San Francisco font, which boosts readability.

Overall, these changes make using your Mac smoother and more enjoyable.

10.12 “Sierra”: 2016

Sierra was released on September 20, 2016, and included Siri, Optimized Storage, and Updates to Photos, Messages, and iTunes.

10.12 “High Sierra”: 2017

High Sierra, released on September 25, 2017, had a few user-visible features, including Safari, Photos, and Mail updates. The notable innovation in this version is the Apple File System.

10.14 “Mojave”: 2018

Mojave was the version that came up with Dark Mode on September 24, 2018.

10.15 “Catalina”: 2019

macOS Catalina was launched on October 7, 2019, but many of its users complain that 32-bit applications are not officially supported.

Operating System Versions

The first Mac operating systems had two main programs: “System” and “Finder.” Each program had its own version number.

System 7.5.3 was the first version with the Mac OS logo. Later, version 7.6 became the first officially named “Mac OS.”

Before the PowerPC G3 microprocessor, key system parts were stored in read-only memory on the motherboard. This setup helped save space for floppy disks, since early Mac computers lacked hard drives. Only the 1991 Classic model could boot from ROM.

Additionally, this design provided a fully graphical interface. Users did not need a text-only console or command-line mode. Boot-time errors appeared graphically.

These errors showed up as icons or simple messages, often using the Chicago font. In contrast, PCs at that time displayed messages in a mono-spaced font on a black screen. Users had to use the keyboard for input.

To offer this level of detail, the system relied on kernel software in the ROM. This software helped operate Apple computers and licensed clones with Apple-copyrighted ROM content.

Overall, the Mac system falls into two families. The first is the Classic family, based on Apple Computer’s original code. The second is the Mac OS X family, which is UNIX-based and includes the NeXTSTEP system.

Classic Mac OS (1984–2001) Version

Classic operating systems often rely on command-line interfaces. In contrast, they offer entirely graphical environments. This makes them easy to use. Moreover, they feature collaborative multitasking.

However, these systems face some criticisms. They struggle with memory management and lack protected memory. Additionally, extensions for extra functionality may clash.

Often, extensions do not work well together. Sometimes, they only function in a specific order. Consequently, troubleshooting them can be a lengthy, trial-and-error process.

File Systems and Compatibility

The original Macintosh utilized the Macintosh File System (MFS). This flat-file system included a single-level folder.

Soon after, Apple introduced HFS in 1985. HFS uses a natural directory tree system, enhancing file organization. Both systems are compatible.

Most file systems, like DOS and Unix, treat files as byte arrays. They require apps to interpret the byte data. In contrast, MFS and HFS use two branches for their files.

The data fork holds the document’s text or image bitmaps. The resource fork contains structured data, like graphics or sound files.

A file can exist with just a data fork. Alternatively, it may include a resource fork. For example, a text file can hold both the text and its style. Thus, apps that do not recognize the style can still read plain text.

However, these forks create interoperability issues. Copying files from a Mac to another system may separate the source fork. This process often needs coding systems like BinHex or MacBinary.

Compatibility and Transition from Classic to OS X

For PowerPC platform versions before OS X v10.4, no compatibility layer exists. This limitation affects the legacy Mac applications known as Classic media.

Classic media runs an exact copy of OS 9.1 or later within an OS X process. The original Macintosh shipped with OS X and OS 9.2 preinstalled.

Users need to install OS X 9.2 and 10.4 Tiger manually. These versions are not included by default on newer machines. The best classic applications work well in this environment.

Yet, compatibility relies on software written to interact directly with the operating system.

Because OS 9 does not support x86 hardware, Classic Environment cannot run on Intel-based Macs. As a result, many Classic users upgraded to OS X.

However, critics argue that OS X is more complex. Some features from the original Mac OS are missing. This can lead to slower performance on older hardware.

Drivers created for older systems don’t work with OS X. Many older Apple machines lack support. Therefore, a significant number of users stick with the Classic OS. By 2005, reports indicated that most users had transitioned to OS X.

The Shift to Intel Processors

In June 2005, Steve Jobs announced a shift from PowerPC to Intel processors. This move aimed to provide better compatibility for newer Classic applications.

At the same conference, Jobs introduced developer migration kits. These kits included beta versions of Apple software for Intel-based Macs.

In January 2006, Apple released its first Intel-based Macs, including the iMac and MacBook Pro. Not long after that, they launched a mini Mac with Intel Core Solo and Duo processors.

By May 16, 2006, the MacBook was available. Apple completed the transition on August 7 with the Mac Pro.

To assist this shift, Intel-based Macs included Rosetta. This technology allows them to run OS X software compiled for PowerPC systems.

Rosetta operates seamlessly in the background. Although execution may be slower than native code, it offers a consistent user experience.

Mac OS X

Mac OS, officially version 10, has a unique history. It follows the 9th edition and Classic systems. This operating system is based on NeXTSTEP and the Mach Core.

Steve Jobs brought NeXT to Apple, which now uses Unix. Additionally, it incorporates BSD code.

The client version has six major updates. The latest is OS X 10.6, called Snow Leopard. Similarly, OS X includes six significant server versions. The first, OS X Server 1.0, entered beta in 1999.

Both versions share the same architecture. However, server versions include management tools. These tools help manage OS X-based systems, workgroup servers, and web services.

Currently, Xserve runs as the default operating system for server hardware. You can also use it with a Mac Mini or install it on other Macs.

Unlike the client version, OS X Server can run on virtual machines. Emulation software like Parallels Desktop makes this possible.

Finally, OS X serves as a foundation for iOS. It is also the OS used on Apple TV and earlier devices like the iPhone and iPad.

Star Trek Project

In 1992, Apple began a secret project called Star Trek. This prototype aimed to create a macOS version for Intel x86 computers. The goal was to support DOS applications with help from Novell.

At that time, Novell DOS struggled as users transitioned to Windows. Many saw a combination of DOS as a possible alternative.

Unfortunately, the project was short-lived. A new CEO changed Apple’s strategy in early 1993.

Despite this, the team managed to run Macintosh Finder and some basic apps, like QuickTime, smoothly. Later, some code from this project was reused for PowerPC.

Fifteen years after the Star Trek project, Apple officially supported x86 architecture. Apple then transitioned all desktop computers to this architecture.

However, the Star Trek Project did not directly lead to this change. Instead, Darwin’s development included x86 support for OS X 10.0 and later. macOS was fully introduced with the release of Macintosh x86 computers.

68000 Processor Emulation

Although Star Trek software was never introduced, third-party emulators emerged. Programs like vMac, Basilisk II, and Executor let macOS Classic run on Intel PCs.

However, these emulators only support 68000 series processors. Most cannot run macOS versions past 8.1, as they require PowerPC processors.

To use these emulators, you need a Mac ROM image. Many users worry about the legal implications of these images and Apple’s intellectual property rights.

Interestingly, Executor software from Abacus Research & Development stands out. It relies entirely on reverse engineering without using Apple’s technology. Yet, full functionality remains limited, and many programs may fail when running.

Still, these emulators carved out a niche for classic Mac 68000 apps on x86 platforms. Development halted in 2002, but the source code was published in 2008.

Emulators that rely on Mac ROM images often provide near-complete compatibility with macOS. Furthermore, modern x86 processors have drastically improved performance.

During this time, many Macintosh users shifted to PowerPC. This transition allowed them to use OS 8.xx and 9.xx versions easily.

Consequently, software support for PowerPC enhanced performance. Overall, this helped smooth the switch to PowerPC-specific applications while running the 68000 emulator and Classic media apps.

PowerPC Emulation

Developing 68000 emulators posed many challenges, especially for PowerPC support. Emulation code was complex, and performance was a concern.

PowerPC emulation had to compete with actual PowerPC Macs. Many developers created simultaneous versions for both the 68000 Classic and the PowerPC. This reduced the need for emulation.

Moreover, PowerPC Mac users chose faster applications. Over time, Apple stopped selling 68000 Macs.

Consequently, the existing user base quickly dwindled. Even with advanced 68000 emulation, it posed no threat to genuine Macs. Their release was late and immature.

The PearPC emulator can run PowerPC processors for newer macOS versions. However, it is still in early development and slower than local systems.

During the shift from PowerPC to Intel, Apple recognized the need for a PowerPC emulator. Thus, they introduced Rosetta to protect customer software investments.

Before Rosetta’s announcement, many expected poor performance from PowerPC emulators on x86. Surprisingly, Rosetta showed only a slight drop in performance.

Another emulator, SheepShaver, has been around since 1998 for BeOS on PowerPC. In 2002, it became open-source, allowing use on other platforms.

Initially, SheepShaver didn’t work on x86. It required a real PowerPC processor, similar to a hypervisor. While it supports PowerPC, it only works up to macOS 9.0.4. This is due to its lack of memory management unit emulation.

Other emulators include ShapeShifter, Fusion, and iFusion. Additionally, some ran classic macOS with a PowerPC accelerator board.

This method improved speed compared to the m68k series. Performance issues arose from real Macs operating in MMU bypass mode.

Macintosh Clones

Over the years, several manufacturers made Macintosh clones. Companies like Power Computing, UMAX, and Motorola produced these devices.

They ran different versions of the classic Mac operating system. In 1997, Steve Jobs ended the clone licensing program after returning to Apple.

In 2008, Psystar Corporation announced a low-cost computer. This machine ran Mac OS X 10.5 Leopard.

Psystar named its system OpenMac and later Open Computer. However, Apple soon engaged in legal battles with Psystar over these clones.

In 2009, HyperMegaNet UG released a “Macintosh-compatible” computer. This device was sold under the PearC trademark. The company claimed the software license terms were unreadable before purchase.

Therefore, they argued that the restriction against OS X on non-Apple hardware was invalid in Germany. Consequently, PearC computers are now sold outside Germany, including in Spain.