Introduction of the PowerBook and System 7

On 13/05/1991, Apple Inc. released System 7, a major update to the Macintosh operating system introduced during the 1991 Worldwide Developers Conference. Internally code named Big Bang, System 7 represented the most substantial software upgrade for Macintosh computers since the platform’s debut in 1984. The release introduced new system level capabilities designed to improve multitasking, networking, and memory management on Macintosh hardware. System 7 added built in virtual memory support, allowing Macintosh computers to use hard disk space as additional RAM. Apple also introduced Personal File Sharing, enabling users to share files and folders across AppleTalk networks without requiring a dedicated server. The update included TrueType font technology, providing scalable fonts that maintained clarity at different sizes, and Aliases, which functioned as shortcut files linking to applications, documents, or folders. These changes expanded usability and simplified navigation within the Macintosh interface. The operating system also laid groundwork for multimedia features introduced later in 1991, including QuickTime, which required System 7 to run. QuickTime enabled playback of digital video and audio within applications, expanding multimedia capabilities on Macintosh systems. Although System 7 launched in May 1991, Apple introduced the PowerBook portable computer line later that year on 21/10/1991, meaning the operating system initially shipped on desktop Macintosh models before appearing on Apple’s new notebook computers.