System 6
Encyclopedia : S : SY : SYS : System 6
- This article is about the Macintosh operating system version. For the IBM word processor, see System 6 (word processor).
Multitasking
Cooperative multitasking made its Macintosh debut in March 1985 with a program called Switcher, which allowed the user to launch multiple applications and switch between them. However, many programs and features did not function correctly with Switcher, and it did not come with the operating system, so it had to be acquired from Apple separately. System Software 6 featured a much more seamless approach called MultiFinder. MultiFinder originally debuted with System Software 5 (System file 4.2 / Finder 6.0).Multitasking under System Software 6 was optional — startup could be set to Finder or MultiFinder. If MultiFinder were selected, the Finder and its functions continued to run when an application was launched. The MultiFinder environment allowed users to see past the windows of running applications to view Finder icons such as the Trash, or the windows of other applications running in the background.
Differences
- System 6 was the last Apple operating system made in machine code. System 7 and up was programmed in C.
- At the upper right hand corner was the icon of the currently running application; clicking on it would cycle through running applications rather than displaying a menu of running applications to choose from. This was the forebearer of System 7's Application menu. The list of running applications appeared at the bottom of the Apple menu instead.
- System 6 supported only 24 bits of addressable memory, rather than the full 32 bits, and so could address a maximum of 8 megabytes of RAM. There was no built-in support for virtual memory, which was only possible through third-party extensions from Connectix at the time.
- Under System 6, although you could drag a file or folder out onto the Desktop, and the system would then remember that placement, you could not save directly to the Desktop and there was no invisible Desktop Folder as there was under System 7 and subsequent classic Macintosh operating systems. In file "open" dialogs, existing files on the Desktop would show up at the root of the drive.
- File "Open", "Save", and "Save As" dialog boxes would rotate through available disks when one used the Tab key. With the debut of System 7, the Tab key was repurposed to shift the input focus from the file name field to the window showing the contents of the currently active disk or folder. These dialogs did not contain the "New Folder" button of later versions, although third party extensions made that functionality available.
- The Apple menu was not as extensively editable as under System 7 and later classic Mac OS. The only items that could exist under the Apple menu were mini-programs called Desk Accessories, which were installed and removed with the aid of a program called "Font/DA Mover". The Chooser, the Scrapbook, and the Control Panel were Desk Accessories, and only a maximum of 15 could be installed at one time. There was no "Apple Menu Items" folder.
- The Control Panel, as noted, was a Desk Accessory. The items that would be known as Control Panels under System 7 were called control panel devices, or 'cdevs' ('cdev' being the file type of these files), and were placed at the root of the System Folder rather than in a dedicated subfolder. Items with this file type were picked up on by the Control Panel desk accessory, which would include them in a scrollable list of controls and settings. In this way, the Control Panel was conceptually closer akin to Mac OS X's System Preferences than to System 7's "Control Panels" folder. System behavior modifiers that did not include a control panel interface — these would be called "Extensions" under System 7 and beyond — were known as 'INITs' (again, for their file type, which was 'INIT') and were also placed at the root of the System Folder.
- The Trash (or Wastebasket in the British version of the OS), under System 6 and earlier, would empty itself automatically when one quit or, if MultiFinder were not running, when one launched an application. System Software 4.7 (System file 3.0 / Finder 5.1) introduced Trash "bulging", i.e., when the Trash contained files, it would gain a bulged appearance.
- System Software 6 did not have aliases; it did not have custom icons (and icons did not appear in the "info" window of a file, folder, or disk); and although it supported color for applications, most of the Finder and System-dialog interfaces were in black and white. Since System Software 5.0 (System file 4.2 / Finder 6.0) the Finder did support coloring of icon outlines on a color-capable Mac, and System Software 5.0 was the first to use this ability for Finder labels. The Labels (called Colors in System Software 6) menu did not get displayed on a black and white Macintosh.
- MultiFinder by default ran desk accessories in a special application called DA Handler, since the Finder's heap was not resizable. System 7 and later Finder run desk accessories in the Finder, since if the Finder run out of heap space, it can use memory from the system heap, which can be resized. Both can be overridden by using the Option key, which run the desk accessory in the current application.
Version History
| Version Number | Release Date | Computer |
| 6.0 | April 1988 | |
| 6.0.1 | September 19, 1988 | Macintosh IIx |
| 6.0.2 | Late 1988 | |
| 6.0.3 | March 7, 1989 | Macintosh IIcx |
| 6.0.4 | September 20, 1989 | Macintosh IIci and Macintosh Portable |
| 6.0.5 | March 19, 1990 | Macintosh IIfx |
| 6.0.7 | October 15, 1990 | Macintosh Classic, LC and IIsi |
| 6.0.8 | April 1991 |
External links
| History of the Apple Macintosh Operating Systems |
|---|
| Mac OS>Classic Mac OS (History): System 6 · System 7 · Mac OS 8 · Mac OS 9 |
| Mac OS X (History of Mac OS X>History): Public Beta · v10.0 · v10.1 · v10.2 · v10.3 · v10.4 · v10.5 |
| Mac OS X Server: Rhapsody (OS)>Rhapsody · Mac OS X Server 1.0 · Mac OS X Server |
| Other OS projects: A/UX · Taligent · Copland · Darwin (operating system)>Darwin |
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