First post, by napierm
Sorry if this is covered elsewhere but I have looked extensively and haven't found this issue.
I have an old dos program I like called TangoPCB Plus which is a nice cad package and is still quite usable for small boards and will do multi-layer boards and is very easy to use. It dates from 1991 and unfortunately is just old enough not to have vesa drivers. I mostly use in on an 486 dos/windows3.11 machine with a Tseng 4000 card but that machine is getting a bit long in the tooth (much like its owner).
So I've loaded dosbox 0.73 and am running under a windows XP SP3 machine. It is a new Dell laptop usually running in a docking station but I don't think that makes any difference.
The program runs fine in vanilla VGA mode and will run in 800x600 mode flawlessly with either the svga_et3000 or svga_et4000 machine setting. Is OK in full screen mode but is a bit too small in a window to do much with. BTW, dosbox is an awesome virtual machine. Great job.
However, the behavior in 1024x768 mode is interesting. The program finds the Tseng hardware and comes up in the right screen resolution. It seems to work just fine except that the lower 1/3 of the screen (or window) is black. It's as if the program is writing to what it thinks is video memory but that portion isn't being displayed. The behavior is identical with with either the svga_et3000 or svga_et4000 machine setting. None of the other machine settings will work at all except at 640x480.
and played with that value some but it didn't make any difference.
I don't have a config.sys and autoexec.bat just has the SET BLASTER ....
Tangop has several video .drv files but the only ones that seem to work here are the vga, orc800 (tseng), and orc1024(tseng) with the problem.
Thanks in advance,
The extroverted engineer stares at the other person's shoes.