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Thread: 5150 Memory Discussion/Question

  1. #1

    Default 5150 Memory Discussion/Question

    In my quest to keep my 5150/5161 all IBM, I ordered two of the 64/256 memory expansion cards, to my knowledge fully populated. I will have a 256 (short length) card available for sale later (PM me, if you are already interested).

    The motherboard has 256k and each card will be fully populated; now, can I configure the cards using the dip switches to allocate only 192 kb or will I have to physically remove chips?

    Also, I've read the article here, so for the first card I know the the DIP switches will be on, off, on, on, but I'm not sure what will the other card be; will it have to be on, off, off, off for starting 448k?

    Does it matter which slot the memory expansion card goes in, in relation to its DIP switch configuration?>

    Thanks,
    Daniel
    Daniel P. Cayea - The Lyon Mountain Company - Plattsburgh, New York 12901
    Vintage Equipment: IBM 5150 * IBM 5161 * ThinkPad 770ED
    Modern Equipment: MacBook Pro 13 * Alienware M15R3

  2. #2

    Default

    I have a 256k card that can give DOS 704K and 896K total RAM (with included software).

    https://books.google.com/books?id=gB...%20AMS&f=false

    http://www.vcfed.org/forum/showthrea...Expansion-card


    Here's the software that comes with it and the manual:

    http://www.vcfed.org/forum/showthrea...886#post460886
    PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step

  3. #3
    Join Date
    May 2006
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    Default

    Quote Originally Posted by lyonadmiral View Post
    ... I ordered two of the 64/256 memory expansion cards, to my knowledge fully populated.
    Quote Originally Posted by lyonadmiral View Post
    The motherboard has 256k and each card will be fully populated ...
    So what you are trying to achieve is shown at [here].

    Card #1: Starting address of 256 KB, and all 4 banks enabled.
    Card #2: Starting address of 512 KB, and only the first two banks enabled (2 x 64 KB = 128 KB).

    Quote Originally Posted by lyonadmiral View Post
    Also, I've read the article here, ...
    Per that page, switches 1/2/3/4 on the card control the starting address of the card.
    The parent to that page is [here], and that page shows that switches 5/6/7/8 selectively enable/disable the various banks.

    Therefore,

    Card #1: 1=on, 2=off, 3=on, 4=on, 5=off, 6=off, 7=off, 8=on
    Card #2: 1=off, 2=on, 3=on, 4=on, 5=off, 6=on, 7=off, 8=off

    Quote Originally Posted by lyonadmiral View Post
    Does it matter which slot the memory expansion card goes in, in relation to its DIP switch configuration?
    No.

  4. #4

    Default

    Thanks!

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