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.
Cleanup/Simplification by:
1) removing irrelevant master flag variable from sim_close_sock and thus sim_err_sock
2) change previous boolean feature arguments (datagram, nodelay, reuseaddr) to flag bits in a single option argument. This allows for features to be added by new flag bits which don't change the calling signatures.
3) changed all status returns to be int (vs t_stat) with success being 0 and error being -1
4) removed unneeded simh specific type references to allow sim_sock to be used by n
Extended API by providing flags to influence socket setup/behavior:
SIM_SOCK_OPT_REUSEADDR Retains prior behavior when sim_switches had -U set
SIM_SOCK_OPT_DATAGRAM UDP socket setup provided for when prior datagram argument was specified
SIM_SOCK_OPT_NODELAY TCP Nagle disable provided for when prior nodelay argument was specified
SIM_SOCK_OPT_BLOCKING Blocking socket mode (detault is non blocking)
This summer a group of us worked together to resurrect the original ARPAnet IMP software, and I’m now happy to say that the IMP lives again in simulation. It’s possible to run the original IMP software on a modified version of the H316 simh and to set up a virtual network of simulated IMPs talking to each other. IMP to IMP connections, which would have originally been carried over leased telephone lines, are tunneled over IP. As far as we can tell, everything works pretty much as it did in the early 1970s. IMPs are able to exchange routing information, console to console communications, network statistics, and they would carry host traffic if there were hosts on the network. The hooks are in there to allow simh to support the IMP side of the 1822 host interface, and the next step would be to recover the OS for an ARPAnet era host and then extend the corresponding simulator to talk to the IMP simulation.
