As discussed in #378
The fixes include:
1. Tightening up the "magic" code so that it can now tell EXE, SAV, and RIM
formats apart.
2. Skipping the loader itself for both RIM10B and ITS RIM. (PDP10 Macro manual
says that RIM10B always includes the loader.) 3. Distinguishing ITS RIM from
RIM10B by the length of the loader block.
4. Adding the slight differences in processing between ITS RIM and RIM10B.
There is no documentation change. -R or the extension .RIM still invoke the
RIM loader, and the code tells ITS and RIM10B apart.
As reported by Josh Dersch in #358
Read hardware notes:
- While the TCCM error bit is a real flop, it is supposed to reflect
the OR of the TCST error bits at all time, so it is updated on read.
- A read of TCDT while the function is RALL clears DONE.
Write hardware notes:
- The TC11 behaves much more like a traditional DECtape controller
than a typical PDP11 peripheral. In particular, execution is
initiated/controlled by any write to TCCM, rather than setting
the GO (DO) bit. Unless the function is STOP or STOP ALL, writing
TCCM will put the selected tape in motion.
- Writing GO (DO) clears DONE (READY) and the error flops in TCST.
- Writing a 0 to ERROR clears the error flops in TCST. Because it
is write 0 to clear (later controllers used write 1 to clear),
the simulator has to know whether ERROR is actually written.
- STOP ALL ignores select errors. Every other function is rejected
if there is a select error.
- An illegal operation (setting ILO) will stop the selected tape.
- A write of TCDT while the function is RALL, WALL, or WTMK clears
DONE (READY). RALL should not be included, but it saved a gate
not to prevent it.
- Because DONE (READY) may not be clear when an operation completes
and DONE (READY) is set, the DT_SETDONE must test for DONE (READY)
not being already set.
ASCII mode for the paper tape reader and punch didn't <quite> work.
In ASCII mode, the <simulator> must create the leader and trailer. The
leader was already there. There shouldn't be nulls in an ASCII file. The
whole point is to be able to prepare and look at input and output files
with a normal text editor.
So this version should work right. It "autogens" trailer more or less
forever. It doesn't really need to return a STOP code on EOF, but users
would probably forget to put form feed at the end, so it doesn't hurt.
1. Implemented Expensive Typewriter mode for TTO.
2. Added ASCII conversion on paper tape punch as well as reader.
3. Changed conversion tables to recognize form feed (014) as FIODEC STOP.
simh.doc Writing a Simulator for the SIMH System
sim_breakpoints.doc The SIMH Breakpoint Subsystem
sim_vmio.doc Adding An I/O Device To A SIMH Virtual Machine
1. Added RP03 support and supporting "SET" commands.
2. Fixed implementation of DPCF (it's a full reset and not blocked by BUSY).
3. Fixed handling of JOB DONE flag (not touched by NOP, SEEK, or RECAL).
The terminal service (in the ISR) forces a CR to be output IMMEDIATELY (before anything in the output queue) when 0212 is seen on input, so it needs to echo as a LF.
I hadn't seen any (other) echo support, so I had assumed the interface was half-duplex, which of course means passwords would appear on the paper!
