SCANCODE 590 (beta)

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SCANCODE 590 (beta)

Postby student0101 » Sun Jan 25, 2015 5:24 am

Hello all; new member, here.

I'm running MS-DOS 5.0 on an HP Compaq 8000 Elite SFF. I downloaded scncd590.zip, and installed and successfully ran SCANCODE in methods 1, 2 and 3 as a command line to simulate Alt-Lsft-1. This keyboard input is needed to select a parallel printer through an ATEN AF142 ParaHub switch. The command also works well when called from a batch file (.bat).

However, when I call SCANCODE from a Synergy DBL runtime (Synergy/MS-DOS runtime version 4.52e, DEC's Dibol variant - URL: http://www.synergex.com) using “xcall spawn” (a command to run an external DOS command) – the runtime crashes and dumps the core. Same results if calling a .bat batch file that contains the SCANCODE command. It crashes with all three methods, 1, 2 and 3. The dumped core (DBLCORE.$$x) is in machine language and hence can't be used to isolate the error that causes the crash.

Does anyone know of a fix or workaround for this? I read the doc files and searched this forum but couldn't find any.

Thanks
student0101
 
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Re: SCANCODE 590 (beta)

Postby Bret » Sun Jan 25, 2015 6:43 am

The vast majority of the forum is related to USB stuff rather than my other programs, so I'm not surprised you haven't found anything. I'm assuming DEC/Synergex wouldn't be of any help since the stuff is so old, but it's conceivable they would let you see their source code (since the program is officially "retired" and no longer of commercial use to them). Admittedly unlikely, but possible.

The only things I can suggest would be some workarounds to bypass the problem. I can think of a few things to try.

SCANCODE is a TSR, and it's never a good idea to install a TSR when you're shelled out of another program. That's guaranteed to cause problems no matter what program you're doing it from. You'll need to make sure that SCANCODE is completely uninstalled from memory before you exit the spawn and return back to Synergex. You'll probably want to issue a SCANCODE Uninstall and then DELAY for a second or so after the SCANCODE Alt-Shift-1.

I'm not sure exactly how SPAWN works, but it probably uses some form/variation of the DOS EXEC function. The DOS EXEC function can't be used directly to execute .BAT files -- .BAT files can only be executed by the command shell (COMMAND, 4DOS, NDOS, etc.). So, you could simply spawn COMMAND and then run the batch file from there (and the batch file could include an EXIT command at the end of it), or spawn something like "COMMAND /C Batch.Bat" (where Batch.Bat is the batch file that includes the appropriate SCANCODE Uninstall and DELAY stuff at the end of it).

You could also run SCANCODE before you start Synergex (or exit Synergex, select the printer, then start Synergex again). Not optimal, but another possible workaround.

Another possibility would be to install another physical parallel port so you don't need to use the switch any more, though I'm not sure how feasible that would be in your situation.
Bret
 
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Re: SCANCODE 590 (beta)

Postby student0101 » Sun Jan 25, 2015 7:50 am

Thanks, Bret. I'll try your suggestions if I can't get a second parallel port. Do you know of any? I've tried several PCI cards: none of them work on MS-DOS 5.0. Also tried Black Box's serial-parallel converter (PIO45A) to use a COM port. That, too, bombed out. Your SCANCODE is my last hope. (The system worked just fine for 25 years on PC-AT's w/ ISA printer cards set up as LPT2.)
student0101
 
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Re: SCANCODE 590 (beta)

Postby Bret » Sun Jan 25, 2015 12:35 pm

Sorry, I've never tried to install a second parallel port on a modern system that doesn't have ISA slots, so can't help you there. I've seen PCI parallel cards in the stores, but have never actually tried one.

There's also a possibility you could use a USB-to-parallel adapter or USB printer if your new hardware has USB, along with my USB drivers. That's probably more complicated than using SCANCODE though (getting USB to work in DOS can be kind of tricky).
Bret
 
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