Do I understand correctly that the QB87 executable is machine code plus some instructions to DOS? So the executable is specialized to a class of CPUs and to DOS. The QB87 executable, despite its abundance of INT instructions, runs decently fast in NTVDM -- about 80× faster than it does in DOSBox. …

... Not sure about QB, but many forms of compiled BASIC, unlike other compiled programming languages, use interrupt handlers extensively, and the numerous INT instructions cause frequent drops to normal core. This degradation of speed could be mitigated if the BASIC compiler can be instructed to …

keenmaster486: I was lucky to find the FreeBASIC suite whole, in order figure out how to make it go. Have you heard of QB64 ? Its IDE looks much like QB4.5's (which I earlier poo-pooed). It's more tolerant of QuickBASIC syntax than FreeBASIC's '-lang qb' is. So far, it's accepted all my code. …

The FreeBASIC compiler balked at just one thing in my big QB87 program. QuickBASIC allows use of real variable 'X' even if array variable 'X()' is used too. Why not? Well, FreeBASIC isn't so free about syntax. With that changed, FreeBASIC executed the program marvelously fast. Comparative speeds for …

...I might again mention the possibility of using FreeBasic, which has compilers for both DOS and Windows, a very good IDE, and the option to be almost 100% syntax-compatible with Quick Basic. It also, by my tests in DOS, creates executables that are some 20 or 30 times faster than their QB …

Be aware, ReactOS NTVDM is just a modified version of DOSBox. Thank you for that warning. I did another speed-test on a QB87 compiled program more typical of my work than the previous test program was. Running time in DOSBox was 19.4× running time with NTVDM. (The former runs in Win 10 64-bit on a …

If your program ... doesn't need fullscreen support then Windows 10 32bit should work. ... DosFreak: Windows 10 32-bit NTVDM works beautifully for my programs. Sound fails, but I don't need it. My adventure with QB87 began on Windows 3.1. I believe 3.1 had a genuine DOS mode, but later Windows had …

... If you want massive speed, try installing DOS in a virtual machine, perhaps in VirtualBox. The advantage of installing Windows XP in your virtual machine and using NTVDM, though, would be that you could share files back and forth between host and guest. ... keenmaster486: this gives me a new …

be sure to set core to dynamic as well. Qbix: yes, core=dynamic made a big difference. Now comparing the DOSBox emulation on a 2 GHz CPU machine to NTVDM on a 1.6 GHz CPU machine, the latter is only about 13× faster. DOSBox is user friendly and fun, but since my BASIC programs are calculationally …

Thank you Dominus, thank you keenmaster486: QB87 installed easily by following the friendly instructions at qbasic.net/en/qbasic-tutorials/dosbox/. It runs, it calculates, unfortunately much too slowly for my engineering work. I think I set DOSBox to maximum speed with cycles=max. Yet my programs …

I assume you mean Quick Basic version 3.00, since that's the one I know of that has QB87.EXE and was released in 1987. To Keenmaster486: You're right, it's QuickBASIC version 3.00. I don't remember why, in 1993, our IT person gave me that 1987 version rather than the 1988 version 4.5, but I can …

From the English language Wikipedia article on DOSBox you'd think that DOSBox was for games while vDos was "for the running the more 'serious' DOS apps (not games)". Nevertheless the author of vDos just informed me that one needs DOSBox to run QB87.exe (because vDos doesn't support the low level Int …