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Thread: Corona PPC400 graphics emulation software

  1. #1

    Default Corona PPC400 graphics emulation software

    Hello all, a few months ago I given a Corona PPC400 which is an IBM portable clone. It came to me in a non-working condition I've been able to work out the variety of issues it had and it is finally booting DOS 3.0 from floppy. No particular reason for 3.0 its just what I had handy, I'm running 5.0 on my Tandy 1000.

    So the point of this post is related to some information I came across in the users manual for this model. From the manual:

    "The super-resolution monitor can be used to
    emulate via software IBM text and graphics modes
    that normally would be displayed using a color
    card with a 200-line color monitor. The PC-400
    and PPC-400 can emulate all seven IBM screen
    modes:
    40 X 25 text (modes 0 euid 1); two pages of
    text are available
    80 X 25 text (modes 2 and 3); one page of
    text is available
    IBM mediiam-resolution graphics (modes 4
    and 5)
    IBM high-resolution graphics (mode 6)"

    I also found a blurb from an old InfoWorld issue that mentions this software graphics emulation as well. Now, I don't have any of the original software for this system and I haven't been able to locate any either so I'm not sure what was used to emulate graphics modes on this machine. Currently if I try to run anything that requires CGA graphics I get an Unexpected Store Exception error. So, does anyone have any ideas what this software may have been?

    Thanks in advance for any input.

  2. #2

    Default

    Here's a pic for those who are interested.


    IMG_5914.jpg

  3. #3
    Join Date
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    Default

    The Corona used system RAM as display RAM, and needed the Corona OEM DOS to balance things properly. If you're running generic MS-DOS, you need to boot and run Corona DOS. Version 1.2x is available on the web; I'm trying to source a copy of Corona DOS 2.x but won't know if I got it for a week or more.

    My PPC-400 only has 128K RAM, and boots up showing 112K available (16K reserved for video). It behaves about as badly as you'd expect; very similar to a 128K PCjr which has a similar system/video RAM layout.
    Offering a bounty for:
    - The software "Overhead Express" (doesn't have to be original, can be a copy)
    - A working Sanyo MBC-775, Olivetti M24, or Logabax 1600
    - Documentation and original disks for: Panasonic Sr. Partner, Zenith Z-160 series
    - Music Construction Set, IBM Music Feature edition (has red sticker on front stating IBM Music Feature)

  4. #4

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    Trixter, thanks for the tip. I had a hunch the solution be something like that. Some googling lead me to the corona dos 1.25 images on winworld but Im having some issues restoring the image. I notice in the readme its a 320k image. Is that correct? Any tips on recreating this disk?

  5. #5

    Default

    Well, in the 3 days that it took my post to be approved I was able to successfully create and boot from the Corona dos image I found. Unfortunately it didnt solve my issue. One interesting difference is that when my machine boots it shows that the full 512k is available to DOS with no reservation for video memory. I Id find in the manual that there are some jumpers on the board for video settings but it seems to indicate those only apply to the desktop models and not the portables.

    Anyway, a newer version of DOS (2.0 or newer) would be a lot more useful. Hopefully that resource comes to fruition.

  6. #6
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    format a: /t:40 /n:8 if on an older DOS, or
    format a: /f:320 if on a newer DOS.
    Offering a bounty for:
    - The software "Overhead Express" (doesn't have to be original, can be a copy)
    - A working Sanyo MBC-775, Olivetti M24, or Logabax 1600
    - Documentation and original disks for: Panasonic Sr. Partner, Zenith Z-160 series
    - Music Construction Set, IBM Music Feature edition (has red sticker on front stating IBM Music Feature)

  7. #7
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    Default

    To write 320k (8-sector) ".img" or ".ima" files from DOS, use
    Brutman's DskImage:
    https://www.brutman.com/PCjr/pcjr_downloads.html

    To write ".imd" files from DOS, use:
    Dave Dunfield's ImageDisk:
    http://www.classiccmp.org/dunfield/img/index.htm

    You can also convert 320k .img/.ima files to ImageDisk using the ImageDisk command:
    320k raw to imd:
    BIN2IMD <image.img> <image.imd> DM=5 N=40 SS=512 SM=1-8 /2

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