| What does it do?
The System Folder contains almost all the essentials of the Mac OS, the software which makes your computer work as you expect (most of the time). Divided into folders, it has the core software to make each part of the hardware work, including peripheral devices, networking, and Internet connections. These provide common services to applications, for using files, drawing on the screen, windows, menus, and so on. The folder also contains extensions to support multimedia, such as QuickTime. Without it, your Mac is dead silicon. How does it work?
When you start up your Mac, it locates the active System Folder (set using the Startup Disk control panel), and loads that copy of the Mac OS, extensions, and so on. The active System Folder is a special folder which has been ‘blessed’ by virtue of its name and contents, including the System file the core of the Mac OS and the Finder, its friendly front end. Recent Macs don’t have ROM chips with the most basic part of the Mac OS in them, but load a software ROM file, Mac OS ROM, from the active System Folder. Towards the end of the startup process, it runs anything located in the Startup Items folder, and when you shut down your Mac, it runs anything located in the Shutdown Items folder. What can go wrong with it?
Plenty! You can normally have just one System Folder on any given volume, but you can divide your disks into two or more volumes if you need to run two different versions of the Mac OS. Having two on a single volume is a sure way to invite confusion and disaster. A lost or damaged System Folder will result in a question-mark being shown persistently at startup: insert a bootable CD to get round this. How can I upgrade it?
Mac OS upgrades come in two types: major releases (for example, Mac OS 9) have to be bought on CD-ROM from Apple dealers. Minor upgrades (for example, Mac OS 9.0.4) can be downloaded from Apple’s support sites or bought on CD, and then have to be applied to the appropriate base version of the Mac OS to accomplish the upgrade. Further info
All the better Mac books explain the structure of the System Folder. Web sites with excellent general coverage include MacFixit, specialising in bugs, problems, and glitches, at www.macfixit.com, and Macintouch, with news and reports on major new products and problem areas, at www.macintouch.com. | |
