use quickbasic compiler or powerbasic/turbobasic instead of bascom perhaps?

Or maybe QuickBasic, which might be more compatible with GWBasic.

stupid overflow problem in bascom and qb:
10 a%=32767 'a is an integer within limit
20 b#=a%*2 'b is a double float and is twice of a
30 print b#
this code has no problem running in gwbasic, but in bascom or qb it bumps a stupid "overflow", probably because a%*2 is above the limit of integer but i am transfering the value to a double. any workaround?

Did you try

20 b#=a%*2.0

This would maybe cast the integer to a float first, so you don't get the overflow.

yeah integer promotion.

you need to do

b# = a%
b# = b# * 2

or try root42's answer.

What about MS PDS BASIC 7.x ? It had MBasic roots and was aimed torwards professionals.

bascom1.0 is extremely stupid, it gives endless "sq" errors(messed line numbers) even for a program with 3 lines, only because its saved by plain text editor and not gwbasic, which seems to add an EOF sign after the last line. the only solution is to load it in gwbasic and save again.