System 7 - Features

Features

Compared with System 6, System 7 offered:

• Built-in co-operative multitasking. In System 6, this function was optional through the MultiFinder; in System 7 it was mandatory.
• Trash was now a formal directory, allowing items to be preserved between reboots and disk eject events instead of being purged.
• Personal File Sharing. Along with various UI improvements for AppleTalk setup, System 7 also included a basic file sharing server allowing any machine to publish folders to the AppleTalk network.
• Aliases. An alias is a small file that represents another object in the file system. A typical alias is small, between 1 and 5 KB. Similar in concept to Unix symbolic links and Windows shortcuts, an alias acts as a redirect to any object in the file system, such as a document, an application, a folder, a hard disk, a network share or removable medium or a printer. When double-clicked, the computer will act the same way as if the original file had been double-clicked. Likewise, choosing an alias file from within an "Open" dialog box would open the original file. (Unlike the path-based approach of shortcuts and symbolic links, aliases also store a reference to the file's catalog entry, so they continue to work even if the file is moved or renamed. Aliases have features of both hard links and symbolic links found on Unix-based systems. All three are supported on OS X.)
• Drag and drop. Document icons could be dragged with the mouse and "dropped" onto application icons to open in the targeted application. Under System 6, one either double-clicked on a document icon to open its associated application, or one could open the desired application and use its Open dialog box. The development of the drag-and-drop paradigm led to a new concept for some applications—such as StuffIt Expander—whose main interactions were intended to be via drag and drop. System 7.5's Drag Manager expanded the concept system-wide to include multiple data types such as text or audio data.
• "System extensions" (small pieces of INIT code that extended the system's functionality) were improved by relocating them to their own subfolder (rather than in the root level of the System Folder itself as on earlier versions), and by allowing the user to hold down the Shift key during bootup to disable them. Later versions of System 7 offered a feature called "Extensions Manager" which simplified the process of enabling/disabling individual extensions. Extensions were often a source of instability and these changes made them more manageable and assisted trouble-shooting.
• "Stationery", a template feature that allowed users to save often-used document styles in special format. "Stationery-aware" applications would create a new, untitled file containing the template data, while non-aware applications would immediately show a Save As dialog box asking the user for the file's name.
• The Control Panel desk accessory became the Control Panels folder (found in the System Folder, and accessible to the user from an alias in the Apple menu). The control panels themselves became separate files, stored within this directory.
• Under System 6, Control Panels and Extensions were known as CDEVs and INITs respectively. System 7 presented the more user-friendly nomenclature in the interface.
• The Apple menu (previously home only to desk accessories pulled from "DRVR" resources in the System file) now listed the contents of a folder ("Apple Menu Items"), including aliases. Desk accessories had originally been intended to provide a form of multitasking and were no longer necessary now that real multitasking was always enabled. The desk-accessory technology was deprecated, with System 7 treating them largely the same as other applications. Desk accessories now ran in their own process rather than borrowing that of a host application.
• The Application menu, a list of running applications formerly at the bottom of the Apple menu under MultiFinder, became its own menu on the right. In addition, Hide/Show functionality was introduced, allowing the user to hide applications from view while still keeping them running.
• Balloon Help, a widget-identification system similar to tooltips.
• AppleScript, a scripting language for automating tasks. While fairly complex for application programmers to implement support for, this feature was powerful and popular with users, and it remains supported as part of OS X.
• AppleEvents. Supporting AppleScript was a new interprocess communication model for "high-level" events to be sent into applications, along with support to allow this to take place over an AppleTalk network.
• 32-bit QuickDraw, supporting so-called "true color" imaging, was included as standard; it was previously available as a system extension.
• Publish and Subscribe. This feature permitted data "published" by one application to be imported ("subscribed to") by another, and the data could be updated dynamically. Programmers complained that the API was unwieldy, and relatively few applications ended up adopting it.
• TrueType outline fonts. Up to this point, all fonts on the Macintosh were bitmapped, or a set of bitmapped screen fonts paired with outline PostScript printer fonts; TrueType for the first time offered a single font format that scaled to any size on screen and on paper. This technology was recognized as being so important that a TrueType extension for System 6 was also released, along with an updated Font/DA Mover capable of installing these new kinds of fonts into the System 6 System file.
• A newly colorized 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 look of previous versions. Only some widgets were colorized — scrollbars, for instance, had a new look, but buttons remained in black and white.
• A new Sound Manager API, version 2.0, replaced the older ad hoc APIs. The new APIs featured significantly improved hardware abstraction, as well as higher-quality playback. Although technically not a new feature for System 7 (these features were available for System 6.0.7), Sound Manager 2.0 was the first widespread implementation of this technology to make it to most Mac users.
• System 7 paved the way for a full 32-bit address space, from the previous 24-bit address space. This process involved making all of the routines in OS code use the full 32 bits of a pointer as an address — prior systems used the upper bits as flags. This change was known as being "32-bit clean". While System 7 itself was 32-bit clean, many existing machines and thousands of applications were not, so it was some time before the process was completed. To ease the transition, the "Memory" control panel contained a switch to disable this feature, allowing for compatibility with older applications.
• System 7.1 marked the advent of System Enablers, small extensions that were loaded at startup to support Macintosh models introduced since the last OS revision. Under System 6, Apple had to introduce a number of minor revisions to the OS solely for use with new hardware. Apple introduced an unprecedented number of new Macintosh models during the System 7 era, leading to some confusion over which System Enabler went with which computer(s).