I'm a bit confused as to how to go about loading two MIDI drivers in SpG. I don't really understand how DOSBox works, and therefore, don't know if I can be of any help. (I'm not a programmer -- so please bare with my ignorance.)
As I understand it, when DOSBox loads, there's support for a PCI MIDI device configured with IRQ 5 and I/O 330H -- which emulates a MPU-401 MIDI Interface, sort of. (MPU-401 is hardwired to use IRQ 2/9, only.) When I load the SpG "VAPIMPU" driver, I tell it to look for a MPU MIDI interface at I/O 330H. Normally, if the MPU interface ISN'T using IRQ 2/9, you have to also tell the driver which IRQ it IS using. But for some reason, this isn't necessary under DOSBox...even though it states the Sound Blaster is using IRQ 5.
If I want to load the driver for a SECOND MIDI Interface, I typically use the "SAPIMPU" driver, and indicate what resources the second interface is using. For example, SAPIMPU /irq:7 /addr:300
By ommitting the "/irq:7" parameter, the driver then 'assumes' IRQ 2/9 is being used...the MPU-401 default IRQ.
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Presently, under DOSBox (with the copy of SpG I uploaded), I would load the drivers and program in this manner:
/spg/
vapimpu.com /addr:330 (The MPU driver loads.)
spg.exe
So, if I wanted to add support for a second "MIDI Port" (Interface), I would typically do something like this:
/spg/
vapimpu.com /addr:330 (The MPU driver loads.)
sapimpu.com /irq:5 /addr:300 (The second MPU driver loads.)
spg.exe
Once in SpG, pressing "F" from the MAIN screen will present a FILE MENU. Repeatedly pressing "M" while in the FILES menu will switch between the type of files that can be loaded: MIDI, SNG, etc. Once a file is loaded, moving your cursor to the "PORT" column lets you output that channel to the MIDI device controlled by either the VAPI or SAPI driver. i.e., VAPIMPU is sending MIDI data to the first soundcard's MIDI port, Port 1, while SAPIMPU is sending data to the SECOND sound card on Port 2.
Pressing "V" from SpG's MAIN screen will give you a better 'veiw' of the MIDI tracks and channels being used.
Hope this makes sense. 😀
Basically, I would need to know HOW to access the SECOND soundcard; what IRQ and I/O address to tell SpG where to look for the second MIDI device.