Paolo_R wrote:What about emulating:
LH BTRIEVE /E /M:48 /P:4096 /T:\CLARION3\CLARION.TRN
I don't know what the BTRIEVE command does. Everything else is not needed since DOSBox already has enough FILES, wastes no space on BUFFERS and STACKS, and has a MOUSE driver and DOSKEY style command line editing built-in.
umb=true basically simulates the combination of EMM386 NOEMS and DOS=UMB. You need both in real DOS to get UMB support, although you can use e.g. UMBPCI instead of EMM386 (pickier on hardware, but better software compatibility). ems=false corresponds to the NOEMS option, although NOT loading EMM386 at all would also correspond to ems=false.
Note that the need for UMBs is much less in DOSBox compared to real DOS, as they're mostly used to "LH" drivers into, and as said above most of the more common drivers are built-in with DOSBox and don't take up any emulated memory. So you have enough free memory even without all these DOS memory management shenanigans of unhappy memory.