The goal being to have output to physical serial ports complete without host
OS level buffering so that what is transmitted via the serial port has correct
timing with respect to I/O completion status within a simulator.
Linux, OS X, and various other *nix host platforms still need work here.
These changes facilitate more robust parameter type checking and helps
to identify unexpected coding errors.
Most simulators can now also be compiled with a C++ compiler without
warnings.
Additionally, these changes have also been configured to facilitate easier
backporting of simulator and device simulation modules to run under the
simh v3.9+ SCP framework.
Added support for per line tcp listen ports.
Added support for per line outgoing tcp/telnet connections.
Removed DEV_NET from pdp11_dz and pdp11_vh emulators to allow proper restore of
Fixed Ethernet formatting of open device names
Fixed serial generic naming to accomodate for the fact that an OS list of serial devices might not include devices which are already opened.
It also modifies the HP 2100 and PDP11 multiplexers to add serial support as demonstrations of the capability that, one day, might be extended to all simulators. I have tested the HP support, but I relied on Holger Veit to test the DEC stuff, so I can't guarantee that it works. I also relied on Holger to test under Linux, so the same caveat applies.
The changes needed in the device simulators are relatively small. For example, if you look at the patches for "hp2100_baci.c", you'll note that most of them are documentation changes. The only things of note are:
- an expansion of the TMXR initializer
- additional code in the "attach" routine to try attaching a serial port
if attaching a socket fails
- additional code in the "detach" routine for the same reasons
The HP MPX device (hp2100_mpx.c) needs a tiny bit of additional support from the ATTACH and DETACH commands. Specifically, SCP was modified to set a flag ("sim_unit_ref") to indicate whether ATTACH MPX or ATTACH MPX0 was done, i.e., to differentiate between a device and a unit attach (recall that SCP treats these as both referring to unit 0). This is needed because the socket attaches (logically) to the device, whereas a serial port attaches to a line. Without this flag, the attach routine cannot differentiate between ATTACH MPX and ATTACH MPX0, as the distinction is lost by the time the VM's attach routine is called. This support isn't needed for the HP MUX device because the socket attaches to a different device than the lines do.
MPX also requires a bit more work due to the capability to mix serial and Telnet lines on the same multiplexer (BACI is a single-line terminal device).
The attached PDF contains revisions to the "Writing a Simulator for the SIMH System" publication that documents the additions and changes to the multiplexer library for serial port support. User documentation for serial port support currently exists only in the initial comments in "sim_tmxr.c"; I will add the appropriate text to the "SIMH User's Guide" if we decide to add this to the release version.
