i been messing with my old dell laptop which has an acer 22" lcd external monitor hooked up to it thru a port replicator.

been trying to troubleshoot this nagging little problem where the external mon dont display in certain situations (dos, debian installer, puppy linux, bootit baremetal boot manager), but does most of the time (all windows,debian wheezy & squeeze, mint, crunchbang,knoppix & kanotix live cd's).

been poking around xorg.conf in the systems that display but haven't learned anything.

yesterday I installed deb71 netinst without desktop & the external monitor displays with just the terminal running, hence my question what file would i look at to try & determine why its working in debian in terminal mode?

Probably a bios setting to tell the hardware which/both display to use.
Unless the dock/replicator is interfering.

Generally once a x starts it loads higher level 'drivers' and takes control of the hardware.
Maybe the KMS is doing similar in debian, even without the bios setting.
What video hardware and drivers are you using?

I have a lappy with a busted screen and an external monitor (VGA-out on the laptop itself), with the bios set to 'both'.
All the POST and boot messages as well as 'real-mode' DOS and non-x linux shows on both (well it used to, and still would if it wasn't stuffed) but once X or windows starts the video driver takes over and displays as per the software settings.
This was problematic on windows as I had to turn on the second monitor using the GUI . Luckily I remembered VNC was already installed , although I haven't bothered booting win on it in over a year now...

thanks ,i'll check the bios settings.

nvidia geforce2 graphics card, i believe, vga out & in.

i also recall having to fiddle with properties in windows to get both to work. something about twinview-cloning as i recall.

no biggie as the big monitor works for most systems. i rarely boot to dos & the boot mgr is only there to choose an op system.

i was disappointed that puppy wouldn't show up on the big mon tho, only live cd ive found that doesn't.