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Thread: How to Create working TRS-DOS 2.x disks?

  1. #1
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    Question How to Create working TRS-DOS 2.x disks?

    Ok so I know how to create working TRS-DOS 2.x disks that are bootable in an emulator but when tried in my Model I they don't work. Any ideas? Something about the DAM marks. Any help appreciated.
    *FrankG*

  2. #2

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    Recently I've created TRS-DOS boot disks, both 3,5" and 5,25", using .IMD images and ImageDisk 1.7. Only "Double-step" setting needs to be adjusted (right now, I don't recall how it was set, it depends on the drive you installed, DD or HD). IMD images are easily converted from DMK format (.DSK image files found in most of the rom sets out there) using the DMK2IMD tool provided in the same package as ImageDisk.
    The most tricky part must be the PC motherboard disk controller+5,25" drive pair, not all of them work. You can use a tool that IIRC can be downloaded from Dave Dunfield's page and checks the PC setup compatibility. The 3,5" drives usually work flawlessly.

  3. #3
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    The problem is indeed in the DAM for the directory area. F9 and FA marks are used in Model 1 single-density mode and cannot be written using standard PC floppy controllers (even those that do support single-density). You can use a Catweasel and Tim Mann's software to write the floppies from a DMK file. however.

    There may be patches to TRSDOS to get around this; I'm not certain.

    Even later (e.g. WD1793) TRS-80 floppy controllers cannot differentiate the FA address marks when reading. This is why the double-density conversion kits for the Model 1 kept the original controller for SD mode and added a second for DD.

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    Check out page 19 of this file:

    http://www.tim-mann.org/trs80/doc/Dsmblr.txt

    The BASIC program described under the heading "Model I TRSDOS patch" will patch TRSDOS 2.3 such that an emulator copied
    diskette will boot correctly in the Model 1. Works Great!

    Cheers!
    Kevin

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    jltursan: I'll try that and see if it will work for me. My floppy drive is a 5.25 dd drive

    Chuck: As i figured a software hiccup. I know my controller can handle SD mode it's an Adaptec 1542.

    Kevin: I'll try that BASIC prgram and see if it works.

    Thanks all.
    *FrankG*

  6. #6
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    jltursan: can't get IMD to work on my PIII system which is what I use as my "TRS-80"

    Kevin: That basic program did not work for me.
    *FrankG*

  7. #7

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    Forget about XP and above, IMD does only work under DOS and Windows 95/98 (the last is the one I'm using), which one do you have installed in your PIII?, other than that, ImageDisk is a very "nice" program that even works in a Windows 7 machine (no disk copying of course, just showing the menu screen).

  8. #8
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    Maybe Dave needs to include some code. Trying to use IMD under 2K/XP/7 seems to be more common nowadays:

    Code:
    //  WinEnhanced - Are we running under Windows?
    //  -------------------------------------------
    //
    //    Returns 1 for Windows NT, 2 for Win95  or 0 for plain old DOS.
    //
    
    int WinEnhanced( void)
    {
    
      union _REGS
        regs;
    
      regs.x.ax = 0x1600;
      _int86( 0x2f, &regs, &regs);
      if ( regs.h.al & 127)
        return 2;
    
    //  We stil may be in NT.  Check for OS version 5.50.
    
      regs.x.bx = 0;
      regs.x.ax = 0x3306;			// get true version
      _intdos( &regs, &regs);
      return (regs.x.bx == 0x3205) ? 1 : 0;
    } // WinEnhanced

  9. #9
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    Forgot to mention. My PIII TRS-80 is running MS-DOS 5.0. So straight DOS, no Windows. Had this problem before were the only thing it would run on was a Tandy 1000! And I don't really feel like setting that machine up right now just to run ImageDisk. So I guess I'll stick with TRS-DOS 2.7DD. Which does seem to work after being created in the emulator. This was Tandy's double density version of DOS and it does support my Aerocomp DD controller board. Or LDOS.
    *FrankG*

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