To take advantage of 32-bit addressing you must be running System 7.0 or higher. Many Macintosh models can enable 32-bit addressing in the Memory control panel.
Older Macintosh II models will need the 32-Bit System Enabler or MODE32 from Connectix to provide the capabilities of 32-bit addressing. Models that require this utility are the Macintosh II, IIx, IIcx, and SE/30. Other models, like the Plus, SE, and Classic can't use 32-bit addressing.
You would use 32-bit addressing if you have more than 8MB of physical RAM installed in your computer. Alternatively, you can use 32-bit addressing in conjunction with virtual memory to expand your memory to any arbitrary amount up to the available space on your hard disk. Remember, however, that Apple recommends the amount of virtual memory not exceed double the physical memory present in your Macintosh. Setting virtual memory higher causes significant performance degradation.
The Memory Control Panel lets you select between 24-bit operation and 32-bit (addressing) operation. Changes take effect when you restart. When you run in 32-bit mode, it's important that your applications be 32-bit-compatible. Most current releases of application software are compatible. Check with your software publishers for information about a specific product.
Follow these steps to run in 32-bit mode:
1) Open the Memory control panel.
2) Select 32-bit addressing.
3) Restart your computer to run in 32-bit mode.
Article Change History
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12 Sep 1994 - Reviewed for technical accuracy, revised formatting.
02 Mar 1993 - Revised to add 32-Bit System Enabler information.
21 Aug 1992 - Revised to include information on MODE32.
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