Microsoft KB Archive/38092

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Disabling Shadow RAM on ALR 16386/20386 Computers in Windows PSS ID Number: Q38092 Article last modified on 01-23-1992 PSS database name: W_Win3

2.03 2.10 2.11 3.00 3.00a



The Advanced Logic Research (ALR) 16386 and 20386 systems reserve 128K of 32-bit RAM for swapping system BIOS and EGA BIOS codes from ROM. Execution of the BIOS code in RAM occurs much faster than execution from ROM. This swapping (or shadowing) increases speed up to 300 percent for the 16-bit system BIOS code accesses and increases speed up to 1200 percent for the slower 8-bit EGA BIOS code.

The BIOS swaps ROM to RAM automatically on system power-up and on subsequent system resets. For testing purposes in Windows/386, you may wish to disable this feature. Two methods available to bypass the shadowing are as follows:

  1. To temporarily disable the shadowing, press the F1 key during the system initialization at power-up. If this solves a problem you are experiencing with Windows/386, you may wish to permanently disable this feature.
  2. To permanently disable the shadowing, set the system board switch position 5 to OFF.

Additional reference words: 3.00 3.00a 3.0 3.0a 3RD_PARTY

Copyright Microsoft Corporation 1992.