IBM 5100 General Comments


This page is for user comments, or to put notes to answer comments/questions I’ve had over time.

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3 thoughts on “IBM 5100 General Comments

  1. Greetings! As you are one of a few people who actually use 5110, I want to ask if I see a blank plane on the cassette slot, does that mean it is a Model2 5110? What is the major difference between model 1 and 2 except the cassette drive and APL/Basic?
    And also: it is a logical choice to buy a 5110 these days for 10000USD?
    Thanks a lot.

    1. Hello! Ah yes my information about the Type 1 vs Type 2 isn’t in an obvious location. It is in the Tape section since that is mainly the difference between them:

      So yes, a blank panel where the cassette would go (meaning lack of the internal tape) is a Model 2 5110. That’s really the only difference, as either Model 1 or Model 2 could have 16 to 64KB and any of the communication cards could also be used in either model. That said, keep in mind that an internal tape cannot be easily added to a Model 2 — mainly, the BaseIO card (attached to the CPU) lacks some circuitry to control the tape.

      As far as the software, either Model 1 or Model 2 could also have the APL or BASIC ROS cards. There were some APL-only (Type A), and BASIC-only (Type B), and mixed (Type C) models.

      Last year (2022), a very complete IBM 5100 went for nearly $10k (full memory, full communication cards, and APL/BASIC and in very good condition). From two sources, we know only about 30,000 units were made — this is across all of the IBM 5100/5110/5120 (not EACH, but altogether). That means, approximately, there only existed about 10,000 of each of those models. Of those, it is estimated only about 10% of them were APL models. These weren’t “massed-produced” in the same way as other early computer systems. I think this puts them on par in rarity as a SOL-20 — which is to say, barely 1 a year becomes available to collectors. Things you can find essentially any week might be in the under $500 category – but something more rare like this, $2000-$5000 may be more appropriate (depending on cards and condition). At least, that’s how I think of it — I think in terms of how many days or how much airplane tickets or gas I’d have to use to find a particular system. It’s not 100% accurate (there is no standard price here), but I think it gets to a more fair “finders fee” type price. And because of the original quality, I do think many of these systems will still function – if there is one that doesn’t work, it’s hard to say how that effects value (like a non-working CRT may be easier to deal with than a non-functional ROS card). But that said, there is no guarantee how long they’ll continue to function. The silver MOSFET type chips that contain the boot up software is still a mystery and “unobtainable” replacements.

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