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Ruuds Diagnostic ROM - 4 KB of RAM at Address A0000


EXAMPLE #1

You may be lucky and have an EGA card (or VGA card) that puts video RAM at A0000 (640 KB) even though the card is uninitialised (repeat: unitialised).  My fully-populated IBM EGA card and my AST-3G card are not in that category.


EXAMPLE #2

Use of the RAM card shown at here, the 'Lo-tech 1MB RAM Board'.

On that card, switch 2.3 would be turned on to provide RAM between addresses A0000 (640 KB) and AFFFF (704 KB).
That is 64 KB of RAM, but it accomplishes '4 KB of RAM at address A0000'.


EXAMPLE #3

Use of the RAM card shown at here, the 'Monotech MicroRAM' card.

On that card, switch 'A000-B000' would be turned on to provide RAM between addresses A0000 (640 KB) and AFFFF (704 KB).
That is 64 KB of RAM, but it accomplishes '4 KB of RAM at address A0000'.


EXAMPLE #4

Use of the RAM card shown at here, the 'IBM 64/256KB Memory Expansion Option'.

If you use the switch settings pictured below, the card will present RAM past A0000 (640 KB).

POTENTIAL PROBLEM:  This card uses dynamic RAM, not static RAM. It is unsuitable if there is a dynamic RAM refreshing problem on the motherboard.

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EXAMPLE #5

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EXAMPLE #6

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