Transfer files to/from N* CPM image?

Dave Dunfield dave09 at
Tue Apr 20 21:35:57 CDT 2010

> > Yeah! - that appears to be the case. I use this technique lots under NorthStar
> > DOS (where I have utilities that can read/write to any of the I/O devices),
> > and I *assumed* that the Horizon implementations of CP/M would have at least
> > one input device pointed at the secondary serial port - however this appears
> > to NOT be the case :-(
> >
> >   
> Depends on what implementation you have.  I have three different
> commercial ones with differing behavior and one I built with
> interrupt driven (buffered) IO.  It's more what the BIOS writer did
> than what CP/M can do.  Most BIOS are near minimal implementation.

I have three different commercial implentations for the Horizon .. a couple of
different versions of the offical NorthStar CP/M release, LifeBoat CP/M for the
Horizon and one called Xitan.

I tested all of them this afternoon, and none of them appear to have a hardware
device mapped to read the secondary serial port -- some of them have devices
mapped to write to it, and some of config/gen programs allow you to select you
printer to be on either the parallel or secondary serial port...

Oddly, I did find code to read it - right next to the code that writes it, but
none of the devices activate that code (I set a breakpoint in it and tried

> A handy tool.    CP/M is simple and the easiest way is through the
> console port and using PIP or DDT (hand entered simple program)
> to do console input capture.
> Then a simple modem program that does Xmodem transfers will
> be the next level for transfers.

Thats great when you are working with a physical system, however I often
find it easier to work under the simulator (single PC)... especially when
the hardware has been stored away as most of my collection is - the newly
added "mount reader file" feature I mentioned in my last post will let you
do the PIP thing by stuffing a file in via the console interface.

I wonder if any of the multi-tasking OS's capable of running DOS software
support virtual com port connections between sessions ... this would let
you run the simulator and a terminal emulator capable of xmodem etc.
transfers on the same PC.


dave09 (at)    Dave Dunfield
dunfield (dot) Firmware development services & tools:
com            Classic Computers:

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