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Thread: Tiny Turbo 286 running in a 5150

  1. #1

    Default Tiny Turbo 286 running in a 5150

    The Orchid Tiny Turbo 286 ... found inside a 5150 and running! Wow

    It has an Intel 8088 chip and what I believe is the 286 chip in the upper right of the board. Connects to the CPU socket on the 5150 motherboard.

    5150 BIOS revision is 10/27/82
    256k on the motherboard, 384k on a Quadram board. All ram is 200ns ... but still, this computer is pretty zippy for a PC!
    Infospotter reports 80286 processor installed


    0314192048.jpg0314192055.jpg0314192103.jpg0314192103a.jpg

    This is similar in concept to the Intel Inboard 386 and the Quadram 386XT boards. I didn't even know this little board existed until today. Does anyone know of any other 286 upgrade boards like this?

  2. #2

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    And here is the Checkit benchmark for the Tiny Turbo 286 installed in the 5150

    0314192143.jpg

  3. #3
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    Quote Originally Posted by chris_nh View Post
    Does anyone know of any other 286 upgrade boards like this?
    At http://minuszerodegrees.net/manuals.htm, see:

    * Accelerator 286
    * AST's HotShot 286
    * Hypertec's HYPERACE-286 and HYPERACE-286 PLUS
    * PCSG's Breakthru 286

  4. #4

    Default

    Wow cool, so I guess there were a few of these types of boards... I was reading a little more and found that Orchid had some other models too. They apparently had an earlier board called PCTurbo and another version of the Tiny Turbo called "Tiny Turbo Xtra". Good stuff.

    Maybe someday somebody will find the actual manual for the Tiny Turbo ... I did find the settings, but the full user manual would have more info. I did find the Xtra manual online which contains some relevant info for the Tiny Turbo boards in general, like how the cpu selector switch works.

  5. #5

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    Here is a link for the Tiny Turbo Xtra manual ... Not the same board as the Tiny Turbo, but still with some relevant info for anyone with this board:

    http://www.elhvb.com/mobokive/archiv...s/1632plus.pdf

    And here are the Tiny Turbo switch settings:
    https://stason.org/TULARC/pc/motherb...TURBO-286.html

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    I think that the small "accelerator" boards never became much more than a specialized curiosity is because they don't really add functionality, just CPU speed. They still have to deal with the bandwidth of the original memory and support devices. While it's true that you get the 286-specific instructions, other features, such as protected-mode segmentation and added address range go unused. An 80186 would have been just as effective, since it gives you the same real-mode instruction set.

    By the time the 80286 hit clone status, imported replacement motherboards were available, cheaper and fully-functional. Of course, the 5150 by this time was obsolete with its 5-expansion slot limit and I've only seen a couple of aftermarket 5-slot motherboards for it.

    This should explain why you don't see more of these things.

  7. #7

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    Quote Originally Posted by Chuck(G) View Post
    An 80186 would have been just as effective, since it gives you the same real-mode instruction set.
    One exception is version 7.0 and higher of Norton Utilities, which refuses to run on anything less than a 286 even though it's only using real-mode code. Try to run any of its programs on a NEC V20/V30/V40 (or 80186/88 if you have one that is PC-compatible) and it'll spit out an error message saying "This program requires at least a 286 CPU".

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    It might be instructive to see how the CPU test is being performed.

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    I thought about this a bit more and tried to answer the question "what quirk would differentiate an 80186 from an 80286 in real mode?". I think I know now.

    Consider the following snippet:

    Code:
    mov ax,sp
    push sp
    pop bx
    cmp ax,bx
    On the 8086 and 80186, the value of SP pushed would be the value of the stack pointer after the push; on an 80286 and above, it would be the value before the push.

    That must be what's going on here.

  10. #10
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    Quote Originally Posted by Chuck(G) View Post
    I think that the small "accelerator" boards never became much more than a specialized curiosity is because they don't really add functionality, just CPU speed. They still have to deal with the bandwidth of the original memory and support devices. While it's true that you get the 286-specific instructions, other features, such as protected-mode segmentation and added address range go unused. An 80186 would have been just as effective, since it gives you the same real-mode instruction set.

    By the time the 80286 hit clone status, imported replacement motherboards were available, cheaper and fully-functional. Of course, the 5150 by this time was obsolete with its 5-expansion slot limit and I've only seen a couple of aftermarket 5-slot motherboards for it.

    This should explain why you don't see more of these things.
    If memory serves (excuse the pun) the Intel Inboard 386 had its own ram, yes?

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