TimeDX Help.


Direct Draw Selection.

    On a system with more than one display device TimeDX must be told which display is to be used for testing purposes. This selection will determine which display DMDX uses for the experimenter's display and which display to use for the subject (unless DMDX is run with the command line override switch -display).

    I am not going to provide more help on getting a Multimon (multiple display device) system up and running beyond a few tips, it's not documented very well anywhere (although http://www.realtimesoft.com/multimon/db.asp has some good info) and extremely subject to driver idiosyncrasies. Suffice it to say that you must have drivers that explicitly state that they function with your OS (the drivers are different for '98 and NT) and even then they may still not function (although they are a lot better than they used to be when I first wrote the Multimon stuff). I have had good luck using a S3 Trio 64 Chipset based video card as a secondary display (it doesn't really seem to matter that much what the primary is) with '98's built in drivers. Also, the primary display will be the leftmost PCI card -- dunno about a primary AGP card but I suspect the second display card must be PCI (unless you BIOS has the ability to reassign these positions).
    Assuming you have managed to get a second display functioning and can extend your desktop on to it and otherwise change it's properties and use it for applications without crashing the machine there's a good chance it's working well enough for DMDX.
    As noted elsewhere, if the secondary display is used as the subjects display it cannot have the number of scan lines re-programmed, only primary displays have this ability. While the possibility exists that the primary could be used for the subject's display the usability of the machine is severely hampered if the primary is suddenly at a remote location, about the only way I can think of doing it requires switch boxes or video splitters and the like and if those are going to be used then you may as well skip the complicated nature of using Multimon.

    Under TimeDX and DMDX 1 it was recommended that a secondary display not be part of the desktop, under version 2 this no longer applies. On the contrary, all my testing has been with them as part of the desktop and after seeing what one of Ken's machines did when the secondary display was not part of the desktop you must extend the desktop onto the secondary display for version 2 and 3 of DMDX to correctly function (otherwise both displays will tend to be painted white after a job runs).

    One problem has been bought to my attention and it was on a laptop that could have a second monitor plugged into it. The problem was that on running TimeDX for the first time you get a choice of video drivers, the selected item being number 2 which is the external (but not activated) monitor. Subsequently running TimeDX produced an error. Attaching an external monitor and activating this allowed the video driver to be reset but without one the problem was not readily solvable as TimeDX would crash every time it was run. I have since added a command line switch to force the selection of the primary video drivers, -deviceoverride, and I have also changed TimeDX to pick the first driver in the list by default as it appears to be safer than the last driver.




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