Jaguar makes OS X ready for everyday use
Jaguar, released in August 2002, was the third version of OS X and the first that felt truly feature complete and ready for use as a primary OS. (It was also the first time Apple branded OS X using its internal codename). Jaguar incorporated a number of notable new features and built-in apps that delivered value not available in Mac OS 9. Its popularity compared to its predecessors was also boosted by the fact that new Macs would boot into OS X by default, and that a large swath of developers had begun to release OS X native apps.
Two of the most notable features in Jaguar related to networking. The first was Rendezvous (later renamed Bonjour), which allowed Macs to automatically detect resources like shared printers and scanners, file servers and other Macs offering services on a local network. The second was built-in support for Windows file and printer sharing. This made integrating Macs into Windows environments or a mixed Mac/PC home environment much easier.
Jaguar also enhanced the Mac's file system and graphics capabilities, introduced a more advanced email client and a native instant messaging client (iChat), and included Universal Access features for users with disabilities. Additional software released around Jaguar included Apple's Safari browser, iCal (later renamed Calendar), and iSync, which allowed syncing of calendar and contact data across multiple Macs and other devices like iPods, PDAs and some cell phones.
Panther marks Apple's entrance into the enterprise
Released in October 2003, Panther marked a couple of important milestones for OS X, including the first major change to the user interface -- the brushed metal look that would dominate the UI for more than a decade -- as well as redesigned Finder windows that include the sidebar still in use today.
Probably the most significant change in Panther was the move away from proprietary directories for storing user, group and computer information. Panther and Panther Server introduced support for a new network directory system, Open Directory, built on open standards including LDAP and Kerberos. Open Directory was appropriate for network environments and, because it was based on open standards, Macs could integrate directly with Microsoft's Active Directory.
That meant that for the first time a user could log into any Mac or PC in a company using the same set of credentials and have access to the same set of network resources.
Apple also ramped up security with Panther by introducing FileVault to automatically encrypt and decrypt a user's home directory on the fly. Other notable additions included Fast User switching, allowing multiple users to be logged in at one time; Expose for easily managing open apps and windows; audio and video chat in iChat AV; and the introduction of Apple's Xcode developer environment, which is still in use today.
Tiger's big claim to fame: Support for Intel
Tiger was released a year and half after Panther, in the spring of 2005. Like its immediate predecessors, it boasted new features and apps that remain with us now: Spotlight search; easy scripting with Automator; VoiceOver for reading text; the first iteration of Parental Controls; and Dashboard, which allowed for dynamic HTML widgets to display data in an overlay of the desktop for easy access. (That feature was later replaced by the Notification Center widgets in Yosemite.)
The most significant place Tiger plays in Mac history, however, came several months after its initial release. It was the first commercial version of OS X to run on Macs with Intel processors, the first of which -- the MacBook Pro and first Intel iMac -- stunned the world when they were unveiled in January 2006.
The second OS X transition
Although Tiger was the first commercial version of OS X to run on Intel processors, Apple had actually been hedging its bets for years in case it ever needed to replace the PowerPC chips that had powered Macs since the early '90s; the company had reportedly produced an Intel version of every OS X release. The move away from the old Classic environment and Mac OS 9 apps made for a cleaner move to Intel when it was needed.
The transition to Intel chips was about more than having an appropriate version of OS X ready to go. As with the transition from the classic Mac OS to OS X, Apple needed developer support. Also like that transition, it meant that developers would need to port their apps. Apple planned well for this as it developed and refined the OS X APIs, somewhat minimizing the work needed by developers to make the switch. The Mac by this point had also become a surer bet for developers than when OS X was being developed eight years earlier.
One difference, however, was that Apple didn't have to worry about winning over users. OS X on Intel looked and felt exactly the same as on a PowerPC. Although Apple did need to provide a way to run PowerPC apps for a time, it did so with an emulation engine called Rosetta that ran transparently in the background. From a user perspective, PowerPC apps simply worked, though they did run a bit slower than Intel apps.
The transition also allowed Apple to attract new users since Intel Macs could also run Windows. This was done either through Apple's Boot Camp, which allows a user to boot into either OS X or Windows, or through virtualization tools like Parallels Desktop, VMware Fusion, and VirtualBox, all of which allow Windows (and Windows apps) to run alongside OS X.
The seamlessness of this transition was matched by how fast it occurred. Apple introduced the first Intel Macs in January 2006 and finished moving its complete Mac lineup to Intel processors in just eight months.
Leopard packs in the features; Snow Leopard packs in the improvements
Without a doubt, 2007's Leopard release was the most feature-packed version of OS X ever, boasting more than 300 new features big and small as well as several significant interface tweaks such as the 3D shelf-like Dock. A full list of these features goes well beyond the scope of this retrospective, but here are some highlights.
Back to My Mac offered easy remote access to one's Mac; the Dock gained the ability to preview folder contents using Stacks; iChat gained support for projecting content to other users and remote screen sharing; QuickLook made it easy to preview documents without opening them; Spaces offered users virtual desktops to help organize onscreen content and minimize clutter; Time Machine made backups (and restoring items from backups) incredibly easy; and an application firewall, along with support for digitally signed applications and application sandboxing, improved security.
Leopard also furthered Apple's enterprise goals by supporting access to Microsoft Exchange in its native email, contacts and calendar tools.
Leopard Server included several important new features, particularly for small and mid-size businesses. It offered a simplified setup process and tools designed for ordinary users rather than IT pros. It also included easy-to-manage services for features like email, internal messaging, wikis and shared contacts/calendars. Leopard Server also became easier to integrate as a departmental solution in larger enterprises with an Active Directory infrastructure.
It's worth noting that Leopard shipped later than expected, in October 2007, largely because resources had been pulled from the OS X development team to help finalize development of something new from Apple: The original iPhone.
In contrast to its feature-packed predecessor, Snow Leopard, released in August 2009, focused almost entirely on improving performance. It was the least feature-filled OS X release since Puma in 2001. Snow Leopard was significant for two reasons beyond those under-the-hood updates: it was the first version of OS X not to run on PowerPC hardware and it was the first version to support the Mac App Store, which was introduced early the following year.