TITLE
    DOS Compatibility Card: System Using Large Amount of RAM (9/95)
Article ID:
Created:
Modified: 		15038
3/31/94
9/29/95
TOPIC



    In the About This Macintosh dialog box, the system software on my Quadra 610 with the DOS Compatibility Card is using over 5.5 MB. Before I started using the DOS Compatibility Card, my system software was only using 1.5 MB. Why is there an increase in the size of the system software?

DISCUSSION


    The DOS Compatibility Card comes with a 72-pin SIMM expansion slot. This SIMM slot ships without a SIMM installed. Without a SIMM installed, the Macintosh and the DOS Compatibility Card share the memory installed in the Macintosh. In the PC Setup control panel, the amount of RAM that is shared can be changed in the memory section. The default amount of shared memory is 4 MB. The shared amount of RAM shows up in the About This Macintosh dialog box as part of the System software memory amount.

    The PC Setup control panel allows you to change the amount of shared RAM. This allows you to lower the system software usage, by decreasing the amount of RAM set aside for the DOS Compatibility Card. The PC Setup Control panel also has an ON and OFF switch. This allows you to turn off the DOS Compatibility Card and free up all the shared memory if you aren't going to use DOS. After turning off the PC Setup control panel and restarting, the amount of RAM used by the system software returns to the original amount, in this case 1.5 MB.

    If a SIMM is installed on the DOS Compatibility Card, then there is no shared memory, so the system software remains at the original amount.


    Support Information Services

Document Information
Product Area: Computers
Category: DOS Compatible
Sub Category: DOS Compatibility Cards
Keywords: kwindows

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