Avoid permanent network network hangs when a network transport starts to return errors for various reasons.
These hangs also result in at least one thread in a CPU bound loop attempting to read on a pcap connection which will never be useful again.
When transmit or receive errors occur, the invoking thread sleeps for 1 second and subsequent operations proceed. When the total of read + write errors reaches a multiple of ETH_ERROR_REOPEN_THRESHOLD the current transport connection (usually pcap) is closed and re-opened after a ETH_ERROR_REOPEN_PAUSE second delay. If the open succeeds, we're happy. If it fails, then the link behaves as if it were never attached until some subsequent operator intervention is performed.
Activities which are known to induce this problems include (but are not limited to) when a simulator is running in a Windows Virtual Machine on a Hyper-V host system and the Hyper-V host system performs a SAVE and a subsequent Restart of the Guest Windows Virtual Machine. This operation can occur due to specific operator requests or merely when the Hyper-V host system reboots.
Migrated the XQ help to the hierarchical help model. This is a work in progress which will eventually merge much from 0readme_ethernet.txt into the device help.
Some of this behavior was previously available in the pdp11_xq simulation for the DELQA device variants, but not the DEQNA. This adds the behavior for all ethernet devices.
The helps to avoid MAC address conflicts since the Ethernet physical address is completely user settable, and starts with a static value. Multiple simulators on the same LAN will have conflicting addresses if they don't specifically set unique values.
- A -R flag is forced (attach READ ONLY) when TPC formatted tapes are attached. This should avoid updating file modified timestamps by any simh simulator.
- All write operations to TPC formatted tapes will fail with a write protected status.
1. Treat the SBRM SysPOP like the BRM opcode for calling a subroutine.
2. If the -a (atomic) switch is present with a BRM or SBRM instruction, place a breakpoint at EA+1 rather than EA, since the return link is placed at EA (BRM) or at *EA (SBRM) with subroutine execution commencing at EA+1.
Allow -f switch with Next to move forward in code.
Allow -a switch with Next for "atomic" behavior that excludes interrupts for all instructions.
Update sds_doc.doc to describe the new behavior.
Add -f switch ("force") to the Next command to set the temporary breakpoints regardless of instruction type. This is useful at
the bottom of loops or to avoid going off into unrelated code should an interrupt or memory paging trap occur.
