Date   : Mon, 08 Apr 1985 14:36:00 PST
From   : MMoon.es@XEROX.ARPA
Subject: PD Modem control programs for CCP/M or MP/M

Upon (finally) receiving Viasyn/ComuPro's Concurrent DOS 816, I
discovered a problem: all my public domain modem software expects to
directly control the hardware, bipassing the OS to do status polling;
since Concurrent doesn't give its exclusive attention to the modem
control program, I lose characters when inputting a continuous data
stream at 1200 baud with *anything* else running concurrently.

Have any of you running CCP/M in any of its various incarnations, MP/M
86 or MP/M 816 found a modem control program, either public or
commercial, which can run as a background task?  Has anyone succesfully
hacked a MEX, MDM840, MDM901, or MDM7XX overlay to exist in this
environment?

If not, I have thought that one of the above overlays might be made to
work if it polled a CCP/M AUX device, since Viasyn/CompuPro tells me
these are handled in the same fashion as TTY devices, i.e., a ring
buffer filled by an interrupt driver.  This solution only works on
input, however, as I believe the function code 0FFh must be used to
signal input.  Anybody tried something similar?  I'm flying blind on
this one 'till my System & Programmer's manual arrives, so I don't know
*exactly* what the function codes are or do.

Please advise soonest if you know a solution.

                       MMoon.es@Xerox.ARPA