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Thread: Tandy bios extensions for 286 accelerator board; anyone have docs on them?

  1. #1
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    Default Tandy bios extensions for 286 accelerator board; anyone have docs on them?

    The Tandy 1000 and 1000SX apparantly had custom bios bits that enabled the use fo the Tandy 286 upgrade card.

    Does anyone know what they were? Are they documented anywhere?

    I'm curious whether the card could be initialized with a custom bios in a non-Tandy XT system.

  2. #2

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    I find this unlikely. I had a Tandy 1000A for several years before I could afford the 286 Express card. There wer no changes to the 1000A BIOS to install the card and the 286 Express card was based on a similar card for the XT with a few Tandy specific tweaks.

    I think the 286 express card used the standard trick of being a BIOS extension that loaded on boot. Much like loading the extension for an XTIDE or SCSI card.

    My memory could be wrong, but I wanted to start a dialog.

    I believe the 286 Express card had special tests that verified it was running on a Tandy machine and this may prevent it from running on a generic PC. Do you have a 286 Express available? They were great.
    Last edited by kb2syd; November 30th, 2017 at 07:42 AM.

  3. #3
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    Quote Originally Posted by kb2syd View Post
    I find this unlikely. I had a Tandy 1000A for several years before I could afford the 286 Express card. There wer no changes to the 1000A BIOS to install the card and the 286 Express card was based on a similar card for the XT with a few Tandy specific tweaks.

    I think the 286 express card used the standard trick of being a BIOS extension that loaded on boot. Much like loading the extension for an XTIDE or SCSI card.

    My memory could be wrong, but I wanted to start a dialog.

    I believe the 286 Express card had special tests that verified it was running on a Tandy machine and this may prevent it from running on a generic PC. Do you have a 286 Express available? They were great.
    YOu may be right, it might even work in a non-tandy XT system, I simply can't find any documentation that it did, an dI don't own any other XT-class boxes to test on currently!

  4. #4

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    On boot, when the driver is loaded my 1000A with 01.01.00 bios and 640k shows:

    286 Express (tm) GACD V1.39
    Configured for Tandy
    (C) 1987 PC Enterprises Inc.

    This with no special configuration parameters on loading the driver, just enabling the cache. I believe this is the last version of the 286 Express software

    Some Tandy catalogs that listed it did show it was for the 1200 and XT's so I don't know if there was actually a difference between them. The 1987 catalog, RCS-17B shows this.
    Collection online nonstop since May 1997: http://www.cchaven.com

  5. #5
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    This sounds odd. Do we know the date of the 1000A BIOS and the date the Express card was announced?
    My Wish List: Vintage Mac SCSI->ETHERNET DaynaPORT LINK T DP0801 Manual, Make-It 486 (or other) 80286 upgrades, Hallock Systems gear / disk images, Copy II PC 'Enhanced' Option Board, Earth Computers ISA Z80 cards & TurboDOS disk. TRS-80 Model IV TurboDOS, Pulsar Little Big Board gear, Tandy Videotext Information System (VIS) for Model 16 Xenix

  6. #6
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    The 286 Express Card's manual has a 1987 date. The Tandy 1000's BIOS is dated for 1984, the 1000A/HD's for 1985, the 1000EX/SX/AX for 1986. The card was strictly intended for those computers (except the EX). It will not work in an IBM PC, I tried it and it failed to boot. Subtle differences in the implementation in the expansion bus between the IBM PC/XT and the Tandy 1000s can cause issues with unusual boards like accelerator cards and the Transcopy cards on Tandys.
    My Retro Computing and Vintage Gaming Blog : http://nerdlypleasures.blogspot.com/

  7. Default

    The copy of the 286 Express manual I have, downloaded as PDF, makes no mention of using it in a XT either. I found it interesting that Tandy's 1987 catalog shows it as for the XT and 1200.
    Collection online nonstop since May 1997: http://www.cchaven.com

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