DOS screens blanking out

Discussion in 'Virtual PC' started by Richard Coleman, Nov 19, 2003.

  1. I'm working for a company that are looking to use VPC
    version 5.1, on W2000 PCs (256M RAM, SP2).

    We're trying to run W95 on this, & off this some DOS apps.
    The DOS apps open fine three times.

    Then on the fourth time onward the screen comes up blank/
    black. If you know what the application keys are you want
    to operate (such as closing this) outlines appear which
    are blank, but no characters can be seen. App will close
    OK, so app appears to be working.

    Closing & restarting the W95 VPC session allows us to go
    back to the situation of these DOS apps opening fine three
    times, but not the fourth time onwards.

    These apps work fine on a standard W95 PC.
     
    Richard Coleman, Nov 19, 2003
    #1
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  2. Sorry, should have said.

    This particular app is a Clipper compiled one.
     
    Richard Coleman, Nov 19, 2003
    #2
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  3. Richard Coleman

    pml Guest

    You may consider try the following:
    - For Windows 2000: Installing latest servicepack avalible for your
    language, the current servicepack for English Windows 2000 is SP4.
    - For VPC 5.1: Upgrade to VPC 5.2 (unless you have *hosts* running
    Win98SE/WinME) or you need to use CMOS clock.
    - Use some other DOS version, possibly loading ANSI.sys, instead of using
    Windows 95 just for launching "text mode full screen" DOS-apps. For instance
    the DOS that accompanied VPC ("Dos 2000") or "Free dos". The tricky part is
    to get networking running, DOS networking isn't exactly plug'n'play. You
    will need a DOS driver for the network adapter "bundeled" with VPC
    (Dec/intel 21140 / "tulip") for your application.
     
    pml, Nov 19, 2003
    #3
  4. Richard Coleman

    cb Guest

    I've seen this behaviour quite a lot with not just DOS, but anything that
    switches to text-mode from a graphical mode a number of times under VPC. For
    example I have seen this bahaviour when opening a full-screen DOS-box under
    Win3.x, as well as OS/2 Warp etc. It even happened on Netware 6 as well when
    switching from the GUI to the console.
     
    cb, Nov 19, 2003
    #4
  5. Richard Coleman

    pml Guest

    Under Windows 3.11 it's a common problem with certiain graphics adapters
    that, when entering full screen mode, most of the text is not visible (due
    to miss in initialization). To initialize the full screen mode type "MODE
    CO80" when in full screen. When that has been done, it's possible to switch
    back and forth between window and fullscreen without problem.
    If you do not need to run program in full screen mode you could change
    either properties for that program or the "_default.pif" so it always starts
    in window mode (but note: When entering full screen mode the screen will
    probably go blank).

    Though I find it unlikely that 32-bit OS:es have this problem; at least the
    graphic card manufacturers have probably fixed this bug long ago.
     
    pml, Nov 19, 2003
    #5
  6. Richard Coleman

    Guest Guest

    Thanx for that - have you ever queried this with Connectix
    or Microsoft & have they ever responded?
    Then on the fourth time onward the screen comes up blank/
    black. If you know what the application keys are you want
    to operate (such as closing this) outlines appear which
    are blank, but no characters can be seen. App will close
    OK, so app appears to be working.

    Closing & restarting the W95 VPC session allows us to go
    back to the situation of these DOS apps opening fine three
    times, but not the fourth time onwards.

    These apps work fine on a standard W95 PC.
    ------------------------------
    but anything that switches to text-mode from a graphical
    mode a number of times under VPC. For example I have seen
    this bahaviour when opening a full-screen DOS-box under
    Win3.x, as well as OS/2 Warp etc. It even happened on
    Netware 6 as well when switching from the GUI to the
    console.
     
    Guest, Nov 20, 2003
    #6
  7. Thanx for that.
     
    Richard Coleman, Nov 21, 2003
    #7
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