ntvdm.exe replacement?

Discussion in 'Computer Support' started by Henry T Fiddler, Sep 4, 2004.

  1. Hi ... not sure if these newsgroups have many dinasaurs like myself
    going back into the 80's, but I just posted this at
    microsoft.public.win3x_wfw_dos
    and thought I'd try here also, to reach a wider audience. Here goes
    :) ...

    -----------------------

    Wow ... finally found a newsgroup with some fellow dinasaurs!

    Before launching into my question, I would love any references to
    great websites or other newsgroups to commiserate with fellow "legacy
    dinasaurs". Just upgraded to Win XP Pro a month ago and would
    appreciate some good company!

    OK, now my question. Anyone got any ideas on this problem I'm
    having?

    Way back long long ago (like sometime in the early 80's), I got
    addicted to this 16 bit DOS shareware "PC-Outline". Also, the old
    Borland Turbo Pascal v3 editor. Oh yeah ... there was also Frank
    Bell's Newkey (a shareware version of Prokey). Any of you remember
    those good ole days???

    Well, over the years, been porting from OS to OS, and managing to get
    them all to work just fine up through and including Win 98 SE. I
    knew the perverbial hatchet would fall sometime in the 1st decade of
    the new millennium, and sure enough, with my recent leap into Win XP
    Pro, it has happened, as I am learning all about ntvdm.exe these
    days. :-(

    Managed to get it all working, but the big gotcha is the way ntvdm
    and its components write to the screen in a windowed mode. All is
    fine and hunkey dorey if I go full screen (which is a pain). But in
    an ntvdm emulated DOS window (with title bar, scroll bars, etc), I
    end up with an annoying jerky scrolling. Some old 16 bit DOS apps
    that used "video retrace" are a horror to behold (like trying to run
    through 50 yr old molasses). This was the case with PC Outline until
    I found out how to disable it. And Turbo Pascal appears to have no
    way to disable video retrace. Another real pain is pasting from the
    clipboard into a DOS window (via the control menu's Edit/Paste) with
    the Video Retrace slowness. I get buffer overrun bigtime, tons of
    speaker beeps, and gibberish on the screen. Very buggy Microsoft! I
    found a workaround, which is very kludgy, inconvenient and painful,
    which I won't bother explaining here, unless someone really needs it.

    However even well behaved 16 bit DOS apps (like Microsoft's own
    \window\system32\edit.com that comes with XP Pro), experience an
    annoying jerky scrolling in a DOS window. I have tried on 3+ gHz
    boxes and the speed of underlying processor makes no difference
    whatsoever in the way this emulated display works. I have already
    tried tweaking all the .PIF settings, with various priorities, etc.
    and they have absolutely no effect.

    So, I'm wondering if anyone else has observed this, and if there is
    any known workaround or replacement?

    Thanks all :) !!!
    Henry Fiddler
     
    Henry T Fiddler, Sep 4, 2004
    #1
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  2. Henry T Fiddler

    Linda Guest

    "Henry T Fiddler" <> wrote in message
    news:...
    > Hi ... not sure if these newsgroups have many dinasaurs like myself
    > going back into the 80's, but I just posted this at
    > microsoft.public.win3x_wfw_dos
    > and thought I'd try here also, to reach a wider audience. Here goes
    > :) ...
    >
    > -----------------------
    >
    > Wow ... finally found a newsgroup with some fellow dinasaurs!
    >
    > Before launching into my question, I would love any references to
    > great websites or other newsgroups to commiserate with fellow "legacy
    > dinasaurs". Just upgraded to Win XP Pro a month ago and would
    > appreciate some good company!
    >
    > OK, now my question. Anyone got any ideas on this problem I'm
    > having?
    >
    > Way back long long ago (like sometime in the early 80's), I got
    > addicted to this 16 bit DOS shareware "PC-Outline". Also, the old
    > Borland Turbo Pascal v3 editor. Oh yeah ... there was also Frank
    > Bell's Newkey (a shareware version of Prokey). Any of you remember
    > those good ole days???
    >
    > Well, over the years, been porting from OS to OS, and managing to get
    > them all to work just fine up through and including Win 98 SE. I
    > knew the perverbial hatchet would fall sometime in the 1st decade of
    > the new millennium, and sure enough, with my recent leap into Win XP
    > Pro, it has happened, as I am learning all about ntvdm.exe these
    > days. :-(
    >
    > Managed to get it all working, but the big gotcha is the way ntvdm
    > and its components write to the screen in a windowed mode. All is
    > fine and hunkey dorey if I go full screen (which is a pain). But in
    > an ntvdm emulated DOS window (with title bar, scroll bars, etc), I
    > end up with an annoying jerky scrolling. Some old 16 bit DOS apps
    > that used "video retrace" are a horror to behold (like trying to run
    > through 50 yr old molasses). This was the case with PC Outline until
    > I found out how to disable it. And Turbo Pascal appears to have no
    > way to disable video retrace. Another real pain is pasting from the
    > clipboard into a DOS window (via the control menu's Edit/Paste) with
    > the Video Retrace slowness. I get buffer overrun bigtime, tons of
    > speaker beeps, and gibberish on the screen. Very buggy Microsoft! I
    > found a workaround, which is very kludgy, inconvenient and painful,
    > which I won't bother explaining here, unless someone really needs it.
    >
    > However even well behaved 16 bit DOS apps (like Microsoft's own
    > \window\system32\edit.com that comes with XP Pro), experience an
    > annoying jerky scrolling in a DOS window. I have tried on 3+ gHz
    > boxes and the speed of underlying processor makes no difference
    > whatsoever in the way this emulated display works. I have already
    > tried tweaking all the .PIF settings, with various priorities, etc.
    > and they have absolutely no effect.
    >
    > So, I'm wondering if anyone else has observed this, and if there is
    > any known workaround or replacement?
    >
    > Thanks all :) !!!
    > Henry Fiddler


    You'll get more posters reading a post if you're not so long winded about
    what you're asking.
     
    Linda, Sep 4, 2004
    #2
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  3. On 4 Sep 2004 02:15:17 -0700, (Henry T

    >Way back long long ago (like sometime in the early 80's), I got
    >addicted to this 16 bit DOS shareware "PC-Outline". Also, the old
    >Borland Turbo Pascal v3 editor. Oh yeah ... there was also Frank
    >Bell's Newkey (a shareware version of Prokey).


    >Managed to get it all working, but the big gotcha is the way ntvdm
    >and its components write to the screen in a windowed mode. All is
    >fine and hunkey dorey if I go full screen (which is a pain). But in
    >an ntvdm emulated DOS window (with title bar, scroll bars, etc), I
    >end up with an annoying jerky scrolling.


    This can be expected.

    In full screen mode, DOS text apps write to display memory, either
    directly, via BIOS calls, or via DOS calls. No matter which method is
    used, the SVGA BIOS/chipset's own character set is used, and the
    process is fast. Some "recent" DOS apps such as PC Tools 8 or Norton
    Utilities 7 (don't try *that* in NT) redefined the SVGA text mode
    character set to do prettier pseudo-graphics, e.g. box edged etc.

    In windowed mode, all of those text writes are channeled through wads
    of Windows drivers and some buffering (e.g. so that reads from display
    memory will work) and that is not only very slow, but also uses the
    Windows character set instead of that within the SVGA card. This also
    breaks the look of apps that define custom character sets.

    If you need such apps to run fast while still being able to "see" the
    rest of Windows, I might suggest trying a dual-head SVGA card. If you
    can run Windows on your "larney" screen and your DOS apps on an old
    14" off the other SVGA port, that could be quite nice...



    >-------------- ---- --- -- - - - -

    "I think it's time we took our
    friendship to the next level"
    'What, gender roles and abuse?'
    >-------------- ---- --- -- - - - -
     
    cquirke (MVP Win9x), Sep 4, 2004
    #3
  4. "Linda" <.@.> wrote in message news:<>...
    > You'll get more posters reading a post if you're not so long winded about
    > what you're asking.


    Right ... and please stop wasting our time with your irrelevant
    comments, so we all have more time to write accurate and detailed
    descriptions of our problems. Also, I don't appreciate your hiding
    behind <.@.>!
     
    Henry T Fiddler, Sep 4, 2004
    #4
  5. "cquirke (MVP Win9x)" <> wrote in message news:<>...
    > On 4 Sep 2004 02:15:17 -0700, (Henry T


    > In windowed mode, all of those text writes are channeled through wads
    > of Windows drivers and some buffering (e.g. so that reads from display
    > memory will work) and that is not only very slow, but also uses the
    > Windows character set instead of that within the SVGA card. This also
    > breaks the look of apps that define custom character sets.


    Very logical, and just what I would have thought .... HOWEVER ...

    This explanation would lead one to believe that emulated display
    performance would be highly sensitive to underlying processor speed.
    Ie. faster processors should paint these Windows characters faster and
    with less jerkiness than slower processors. However I have tried this
    out on several boxes with widely varying speeds and the performance is
    identical on all. It appears that the output is governed somehow to
    the clock, so that we could run someday on 100 gHz boxes, and still
    experience this same awful performance!

    > If you need such apps to run fast while still being able to "see" the
    > rest of Windows, I might suggest trying a dual-head SVGA card. If you
    > can run Windows on your "larney" screen and your DOS apps on an old
    > 14" off the other SVGA port, that could be quite nice...


    I have a laptop. I take it on the road and move it constantly. In
    addition, I am convinced that this windowed video performance is
    completely unrelated to processor speed, video ram, video card speed,
    etc. It appears to be something inside ntvdm or one of it's related
    driver modules.

    Thanks for your insights. Any more?
     
    Henry T Fiddler, Sep 4, 2004
    #5
  6. Henry T Fiddler

    CS Guest

    On 4 Sep 2004 11:33:41 -0700, (Henry T
    Fiddler) wrote:

    >"Linda" <.@.> wrote in message news:<>...
    >> You'll get more posters reading a post if you're not so long winded about
    >> what you're asking.

    >
    >Right ... and please stop wasting our time with your irrelevant
    >comments, so we all have more time to write accurate and detailed
    >descriptions of our problems. Also, I don't appreciate your hiding
    >behind <.@.>!


    You may not appreciate her hiding, but at least she's smart enough not
    to use her real E-mail address and then cross post it to many groups.
    You're just asking for SPAM and E-Mail viruses by using a real E-Mail
    address. Of course then you'll probably complain to AT&T and say it's
    their fault. But you'll keep on writing those accurate and detailed
    descriptions of your problems......
     
    CS, Sep 4, 2004
    #6
  7. On 4 Sep 2004 11:42:57 -0700, (Henry T Fiddler) wrote:
    >"cquirke (MVP Win9x)" wrote
    >> On 4 Sep 2004 02:15:17 -0700, (Henry T Fiddler) wrote:


    >> In windowed mode, text writes are channeled through Windows
    >> and buffering (e.g. so that reads from display memory will work)
    >> and that is not only very slow, but also uses Windows character
    >> set. This breaks custom character sets.


    >This explanation would lead one to believe that emulated display
    >performance would be highly sensitive to underlying processor speed.
    >Ie. faster processors should paint these Windows characters faster and
    >with less jerkiness than slower processors.


    You'd think so, yes; I suspect part of the reason it doesn't, may have
    to do with real-time slicing so that other tasks run at the same time.

    When these old DOS apps were written, they generally avoided writing
    text to screen via DOS or even BIOS services as these were "too slow".

    Ironically, those optimizations become meaningless when Windows
    emulates DOS apps; in fact, there may be more code required to emulate
    a "direct" write to display memory than a DOS or BIOS call.

    So although the processor is massively faster, there's considerably
    more code involved. It still seems slower than I'd expect; perhaps
    the impact is because the entire overhead is repeated for each
    character that is written to the window.

    >However I have tried this out on several boxes with widely
    >varying speeds and the performance is identical on all.


    That suggests real-time slicing at character-granularity.

    >Thanks for your insights. Any more?


    Only as above, alas!



    >--------------- ----- ---- --- -- - - -

    IRC is just multiplayer notepad.
    >--------------- ----- ---- --- -- - - -
     
    cquirke (MVP Win9x), Sep 5, 2004
    #7
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