Forum Rules and Etiquette

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This forum is part of our mission to promote the preservation of vintage computers through education and outreach. (In real life we also run events and have a museum.) We encourage you to join us, participate, share your knowledge, and enjoy.

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To put things in engineering terms, we value a high signal to noise ratio. Coming here should not be a waste of time.
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Rule 4: "PM Sent!" messages (or, how to use the Private Message system)

This forum has a private message feature that we want people to use for messages that are not of general interest to other members.

In short, if you are going to reply to a thread and that reply is targeted to a specific individual and not of interest to anybody else (either now or in the future) then send a private message instead.

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Why do we have this policy? Sending a "PM Sent!" type message basically wastes everybody else's time by making them having to scroll past a post in a thread that looks to be updated, when the update is not meaningful. And the person you are sending the PM to will be notified by the forum software that they have a message waiting for them. Look up at the top near the right edge where it says 'Notifications' ... if you have a PM waiting, it will tell you there.

Rule 5: Copyright and other legal issues

We are here to discuss vintage computing, so discussing software, books, and other intellectual property that is on-topic is fine. We don't want people using these forums to discuss or enable copyright violations or other things that are against the law; whether you agree with the law or not is irrelevant. Do not use our resources for something that is legally or morally questionable.

Our discussions here generally fall under "fair use." Telling people how to pirate a software title is an example of something that is not allowable here.

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New user moderation

New users are directly moderated so that we can weed spammers out early. This means that for your first 10 posts you will have some delay before they are seen. We understand this can be disruptive to the flow of conversation and we try to keep up with our new user moderation duties to avoid undue inconvenience. Please do not make duplicate posts, extra posts to bump your post count, or ask the moderators to expedite this process; 10 moderated posts will go by quickly.

New users also have a smaller personal message inbox limit and are rate limited when sending PMs to other users.

Other suggestions
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Different types of Intel Inboard 386/pc's

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    Different types of Intel Inboard 386/pc's

    For some time my notion were - there are two different versions of the Inboard386/pc.
    But is it so ?
    The inboard with 8 bit RAM chips (non parity type)
    ..i have a DOA card with inner sticker:
    fcc id EJM5MYINBRD386PC (Singapore)

    (i have tried a quick repair - but my card is still not working)

    and the Inboard with the 9 bit RAM chips (with parity).

    i have working cards, with inner sticker:
    fcc id: EJM5R7INBRD386PC (made in USA)
    fcc id EJM5R7INBRDAT386 (no - "made in..")
    ..i have not seen any difference in performance the two card compared.

    But looking at the introduction of the Inboard (1987) it seems there is another version

    - with the coprocessor placed above the 80386 socket.
    At first i was septical wether the oldest type only were some Beta version and not up for sale. But some days ago i spotted the older version again in other commercials. So perhaps there IS three types around?

    And today i did search , and there is a RAM piggyback up for auction. (not me selling or buying)

    The box PCIB3120 only says "inboard386" not 386/pc or 386/at, if you search for the model: "PCIB3120" it is made for the inboard386/AT
    and i am speculating - do the oldest type of inboard 386/pc have connections to external RAM card, exactly the same ase 386/at ?? - try and look at old commercial here:

    I have not seen and of the oldest on auction - have any of you seen the oldest Inboard386 type , in person ?

    Again , i do only have Inboard with 8 and 9 chips RAM, so i am only speculating whether the oldest 386/pc and 386/at have the same RAM-expansion connectors.


    The advertisement literally says the IB1200 can accept a piggyback board IB1210 officially up to 2MB expansion for 3MB total. It's likely it would accept the 4MB card also and theoretically 8MB cards but I don't think nc_mike has made further progress at this yet.
    Last edited by cb88; August 11, 2020, 06:15 AM.



      i have seen both the non-parity version (8 chips) and parity version (9 chips) in the wild. The non-parity version seems very rare and might be a later model than the parity version. Regarding memory: i suspect that the inboard 386PC has a total of 4 memory banks with up to 4mb per bank. The memory decoder logic would therefore be able to drive 16mb of memory. The inboard has one bank of 1mb that is not really upgradeable without massive modifications. Since each bank can have 1mb or 4mb of memory, a 12mb expansion may be possible for a total of 13mb memory.



        cb88 - on picture from twitter , the inboard386/pc has like 3 connectors and then 1 connector (for RAM expansion). Like the picture below of the Inboard386/at.
        the 8 chip and 9 chip versions have j1 and j2 each 40 pin.

        stynx - i think the easy solution is upgrading the 2Mb ram card with 1mbit chips , in total 8 mbyte ram
        or perhaps (just a thought) upgrade the 2mb module with one 1mb (soldered) and the free sockets filled with 1mbit chips - in total 5mb extra ram ?
        ..the 1mbit chips only lacks the A9 pin . But i have NO idear if it works :Oo .

        question ..i believe there is only two WE signals to the expansion board - how would you access the third bank ?


          Originally posted by Cimonvg View Post
          question ..i believe there is only two WE signals to the expansion board - how would you access the third bank ?
          You are may be right. But there is one signal line that is unaccounted for.