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.

Here are some obvious examples of when you should not reply to a thread and use the PM system 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.

Reporting problematic posts

If you see spam, a wildly off-topic post, or something abusive or illegal please report the thread by clicking on the "Report Post" icon. (It looks like an exclamation point in a triangle and it is available under every post.) This send a notification to all of the moderators, so somebody will see it and deal with it.

If you are unsure you may consider sending a private message to a moderator instead.

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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C80287XL Math Co-Procesor for 286 motherboards

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    C80287XL Math Co-Procesor for 286 motherboards

    I'm selling "C80287XL Math Co-Processors" for 286 motherboards. This particular model is the best Math Co-Processor made for the 286. It's able to automatically match the speed of whatever 286 processor you throw at it. It's a 40 Pin Ceramic DIP and is in good working condition. Don't leave that Math Co-Processor socket empty on your motherboard - Soup your system to the max and install one of these.

    Info on this Processor at this link:

    I'm selling them for $15 each plus $5 shipping.
    I have 6 for sale.
    Email if your interrested.

    Last edited by barney; July 27, 2012, 06:58 PM.

    Still have any of the 287XL fpu's left? I'm interested in one if you'll send to the UK.



      I still have 4 left. Anybody interrested?


        Originally posted by Megatron-uk View Post
        Still have any of the 287XL fpu's left? I'm interested in one if you'll send to the UK.

        I have an Intel D80287-10 that I'd ship to the UK if you're interested.
        PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step


          Originally posted by Stone View Post
          I have an Intel D80287-10 that I'd ship to the UK if you're interested.
          I'm ideally after the 287XL as I'm running a 16MHz cpu (with plans to try and find a 20/25MHz Harris in the future!).


            I have a Harris 80286-16.

            I think that 80287 FPUs ideally run @ 1/2 to 2/3 of the CPU speed so an 80287-10 would be a good fit for an 80286-16 or an 80286-20.
            PM me if you're looking for 3" or 5" floppy disks. EMail For everything else, Take Another Step


              The 287XL works at up to 12 MHz, as far as I know.

              The 287XL runs at 1/2 the clock speed if pin 39 is pulled low, where the standard 287 will only run at 1/3 the clock speed if the same pin is pulled low. If the pin is high, then both runs at 1/1 the clock speed.

              The main difference is that the 287XL is a 387SX in disguise. Programs will therefore see and treat it as a 387 instead of a 287. Another thing to note is that it is to a larger extent asynchronous to the 286, and will not monitor the execution of ESCAPE instructions as a regular 287 would.
              Last edited by per; August 6, 2012, 01:21 PM.
              Current systems owned by me:
              Vintage:IBM PC/XT submodel 087 ( 1983 ), [Kon]tiki-100 rev. C (1983), Compaq Portable I ( 1984 ), IBM PC/XT submodel 078 ( 1985 ), IBM PC/XT286 ( ~1986 ), 3x Nintendo Entertainement Systems ( 1987 ).
              Obsolete:Commodore A500 ( ~1990 ), IBM PS/2 model 70/386 type 8570-161 ( 1991 ), Atari Lynx II ( ~1992 ), Generic Intel 486SX PC ( ~1993 ), AT/T Globalyst Pentium w/FDIV bug MB ( 1994 ), Compaq 486DX4 laptop ( ~1995 ).


                I have just 2 left. Let me know if you are interrested. Thanks.


                  Hey Barney! Have you tried putting one of these in your Wang? If so, did it work? I'm asking because I put an IIT 2C87 (rated for 20 MHz) in mine and it has problems when running at 16 MHz. At 8 MHz it works just fine though. I don't know what the problem is.
                  Looking for a cache card for the "ICL ErgoPRO C4/66d V"


                    Yes, I did. It's on my Wang and running beautifully. Best damn chip I ever used before.



                      If anybody is still interrested, I still have 2 or 3 more of these Math Co-processors I'm selling. PM me if your interrested. Thanks.