Two Stop Bits | > "Interestingly, MS-DOS also has a separate paper punch API."Where did he p...

> "Interestingly, MS-DOS also has a separate paper punch API."

Where did he pull that one from? No such thing that I'm aware of, and I've had my share of poring over MS-DOS API docs. If you wanted to talk to a paper punch using nothing but DOS, you'd likely have to do it over the serial port at COM1/2, which used the same generic I/O device API as the console (CON)... hence the ability to "CTTY" to those devices.

MS-DOS did implement CP/M function calls (along with the CALL 5 interface itself) to simplify porting code, even when those calls were meaningless in DOS and only returned dummy values. But this paper tape stuff doesn't seem to exist anywhere in DOS, which in turn makes me skeptical about it being in CP/M. When you think about it, it would've been an inexcusable waste to implement such a thing in either of them - seeing as they were disk operating systems, which (as the article points out) had every reason to be as minimal as possible.

Besides, if it was there in MS-DOS, you'd think Ralf Brown would know about it.

spc476 66 days ago
Starting with MS-DOS 2.0, a program has five open files available to it [1], stdin, stdout, stderr, stdaux and stdprn. By default, the first three point to the CON: device, stdaux to the AUX: device (usually the serial port) and stdprn to PRN:. I suppose a paper tape punch could be either AUX: or PRN:, but the reference I'm using (_The MS-DOS Encyclopedia_) doesn't have a reference for a paper tape at all.
[1] Much like Unix programs have three open files.
ddingus 66 days ago
I just looked and MSDOS has a printer API. Maybe that is what the author meant.
In MSDOS, I was able to use:
A mode line may be needed, and was with a tape punch:
MODE COM3:1200,N,8,1,P
And then, given the cable is setup to exchange the flow control signals: RTS, CTS
Then in MSDOS, this would work:
COPY GCODE.TXT COM3
The punch would start cutting paper tape.
I never did the reverse. Not sure how in MSDOS. I used PROCOM then clean up the capture and save to file.
And if one wants a binary, the /B option is needed so MSDOS will send 8 bits, not 7