273. ENHANCEMENT: Burst-fill only the first of two MPX receive buffers in FASTTIME mode.
OBSERVATION: When the 8-channel multiplexer is set for "optimized timing"
mode, buffered characters are transferred in blocks to and from the Telnet
connection. That is, the line service routine will send or receive
characters as long as they are available. This is more efficient than the
"realistic timing" mode, which sends or receives one character per service
invocation. Effectively, this means that up to 508 characters (two buffers
of 254 bytes each) may be sent or received between one CPU instruction or
DCPC cycle and the next. This works well for sending, but it can cause
buffer overflows when receiving.
Consider an application (such as Kermit) that receives large blocks of data
at high speed from a client. The multiplexer is designed to handle this
condition by interrupting the CPU when the first buffer is filled and
filling the second buffer while the CPU is unloading data from the first.
In realistic mode at 19,200 baud, the CPU has approximately 800
instructions or DCPC cycles available per character received. With a
second buffer of 254 bytes, the CPU has approximately 203,000 instructions
available to unload the first buffer after receiving the interrupt
notification. Once started, the DCPC transfer takes no more than 508
instruction times, so the CPU can easily keep up with data arriving at the
maximum baud rate.
In fast timing mode, however, the first buffer burst-fills in a single CPU
instruction time, and, if available from the Telnet connection, the second
buffer fills in the next instruction time. At that point, any additional
characters received will result in a buffer overflow condition. The
problem is that the CPU has no time between the first burst and the second
to empty the first buffer.
RESOLUTION: Modify "mpx_line_svc" (hp2100_mpx.c) to shift from burst
transfers to character-at-a-time transfers when a receive buffer is full
and awaiting unloading by the CPU. This allows the CPU and DCPC time to
read the buffer contents into memory before the second multiplexer buffer
is full. Once the completed buffer is freed, the service routine returns
to burst mode to fill the remainder of the other buffer, permitting the
efficiency of block transfers while avoiding buffer overruns with large
data transfers.
274. PROBLEM: A second connection to the BACI device leaves the client unresponsive.
OBSERVATION: The BACI device supports a single terminal client connection.
If a second connection is attempted, the client connects but is otherwise
unresponsive. It would be better if the client received the "All
connections busy" message that is reported by the terminal multiplexers
(MPX and MUX devices) when the number of connections is exceeded.
CAUSE: The "baci_poll_svc" is calling the "tmxr_poll_conn" routine only if
the port is not connected. The routine should be called unilaterally, so
that it will report an error and disconnect the client when all lines are
in use and another connection is attempted.
RESOLUTION: Modify "baci_poll_svc" (hp2100_baci.c) to call
"tmxr_poll_conn" unconditionally, so that a second concurrent connection
attempt will be rejected with "All connections busy".
275. PROBLEM: The exported program counter name (PC) clashes with other libraries.
OBSERVATION: In HP 21xx/1000 systems, the P register is the program
counter. In keeping with the naming of the other register variables (e.g.,
for A register, B register, etc.) in the simulator, the variable used
should be named "PR". However, for traditional reasons, the program
counter in SIMH is named "PC".
The main CPU module declares its hardware register variables as global, so
that they may be accessed by other CPU helper modules. Unfortunately, the
"curses" library also declares the symbol "PC" as global, leading to
conflicts when it is loaded by SCP. A workaround had been implemented that
renamed "PC" to "PC_Global" in the HP2100 simulator, but that meant that
the new name had to be used when debugging, which was awkward.
CAUSE: A poor choice of global symbol names from the "termcap" library,
which was inherited by the "curses" library.
RESOLUTION: Change the program counter variable name from "PC" to "PR"
(hp2100_cpu.c, hp2100_cpu1.c, hp2100_cpu2.c, hp2100_cpu3.c, hp2100_cpu4.c,
hp2100_cpu5.c, hp2100_cpu6.c, hp2100_cpu7.c, hp2100_dr.c, and hp2100_ipl.c)
to avoid a name clash and for register naming consistency.
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.
265. PROBLEM: Compiling the HP simulator for 64-bit addressing produces many
conversion warnings.
OBSERVATION: Compiling the simulator and defining USE_INT64 and USE_ADDR64
with implicit conversion warnings enabled reveals a number of places where
assumptions were made that addresses would always be 32 bits. This is a
reasonable assumption, as there are no devices (CPU or peripherals) that
can handle gigabyte addressing. Still, many of these assumptions are not
necessary, and some future peripheral simulator may exceed this limit.
CAUSE: Future expansion to 64-bit addressing was not envisioned.
RESOLUTION: Modify source files to ensure that "t_addr" and "t_value"
types are used instead of "uint32" and "int32" types where addressing and
data values may be 64 bits. Also ensure that valid conversions to smaller
sizes use explicit casts.
266. PROBLEM: BOOT devices require a duplicate S-register declaration.
OBSERVATION: All of the peripheral devices that support the BOOT command
set the select code and other parameters into the S register during the
boot process. This direct register access requires an external declaration
that duplicates the one in the full CPU declarations file (hp2100_cpu.h).
A better method that avoids the duplicate declaration would be for the
"ibl_copy" routine to modify the S register on behalf of the caller.
CAUSE: Poor original implementation.
RESOLUTION: Modify "ibl_copy" (hp2100_cpu.c) to take two additional
parameters that clear and set bits, respectively, in the S register on
behalf of the caller. Modify the boot routines for the CPU, DA, DP, DQ,
DR, DS, IPL, MS, and PTR devices to use the new parameters instead of
modifying the S register directly.
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
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.
The makefile now works for Linux and most Unix's. Howevr, for Solaris
and MacOS, you must first export the OSTYPE environment variable:
> export OSTYPE
> make
Otherwise, you will get build errors.
1. New Features
1.1 3.8-0
1.1.1 SCP and Libraries
- BREAK, NOBREAK, and SHOW BREAK with no argument will set, clear, and
show (respectively) a breakpoint at the current PC.
1.1.2 GRI
- Added support for the GRI-99 processor.
1.1.3 HP2100
- Added support for the BACI terminal interface.
- Added support for RTE OS/VMA/EMA, SIGNAL, VIS firmware extensions.
1.1.4 Nova
- Added support for 64KW memory (implemented in third-party CPU's).
1.1.5 PDP-11
- Added support for DC11, RC11, KE11A, KG11A.
- Added modem control support for DL11.
- Added ASCII character support for all 8b devices.
1.2 3.8-1
1.2.1 SCP and libraries
- Added capability to set line connection order for terminal multiplexers.
1.2.2 HP2100
- Added support for 12620A/12936A privileged interrupt fence.
- Added support for 12792C eight-channel asynchronous multiplexer.
2. Bugs Fixed
Please see the revision history on http://simh.trailing-edge.com or
in the source module sim_rev.h.
The makefile now works for Linux and most Unix's. Howevr, for Solaris
and MacOS, you must first export the OSTYPE environment variable:
> export OSTYPE
> make
Otherwise, you will get build errors.
1. New Features
1.1 3.8-0
1.1.1 SCP and Libraries
- BREAK, NOBREAK, and SHOW BREAK with no argument will set, clear, and
show (respectively) a breakpoint at the current PC.
1.2 GRI
- Added support for the GRI-99 processor.
1.3 HP2100
- Added support for the BACI terminal interface.
- Added support for RTE OS/VMA/EMA, SIGNAL, VIS firmware extensions.
1.4 Nova
- Added support for 64KW memory (implemented in third-party CPU's).
1.5 PDP-11
- Added support for DC11, RC11, KE11A, KG11A.
- Added modem control support for DL11.
- Added ASCII character support for all 8b devices.
2. Bugs Fixed
Please see the revision history on http://simh.trailing-edge.com or
in the source module sim_rev.h.
1. New Features
1.1 3.7-0
1.1.1 SCP
- Added SET THROTTLE and SET NOTHROTTLE commands to regulate simulator
execution rate and host resource utilization.
- Added idle support (based on work by Mark Pizzolato).
- Added -e to control error processing in nested DO commands (from
Dave Bryan).
1.1.2 HP2100
- Added Double Integer instructions, 1000-F CPU, and Floating Point
Processor (from Dave Bryan).
- Added 2114 and 2115 CPUs, 12607B and 12578A DMA controllers, and
21xx binary loader protection (from Dave Bryan).
1.1.3 Interdata
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state.
1.1.4 PDP-11
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state (WAIT instruction executed).
- Added TA11/TU60 cassette support.
1.1.5 PDP-8
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state (keyboard poll loop or jump-to-self).
- Added TA8E/TU60 cassette support.
1.1.6 PDP-1
- Added support for 16-channel sequence break system.
- Added support for PDP-1D extended features and timesharing clock.
- Added support for Type 630 data communications subsystem.
1.1.6 PDP-4/7/9/15
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state (keyboard poll loop or jump-to-self).
1.1.7 VAX, VAX780
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state (more than 200 cycles at IPL's 0, 1, or 3 in kernel mode).
1.1.8 PDP-10
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state (operating system dependent).
- Added CD20 (CD11) support.
2. Bugs Fixed
Please see the revision history on http://simh.trailing-edge.com or
in the source module sim_rev.h.
The source set has been extensively overhauled. For correct
viewing, set Visual C++ or Emacs to have tab stops every 4
characters.
1. New Features in 3.4-1
1.1 All Ethernet devices
- Added Windows user-defined adapter names (from Timothe Litt)
1.2 Interdata, SDS, HP, PDP-8, PDP-18b terminal multiplexors
- Added support for SET <unit>n DISCONNECT
1.3 VAX
- Added latent QDSS support
- Revised autoconfigure to handle QDSS
1.4 PDP-11
- Revised autoconfigure to handle more casees
2. Bugs Fixed in 3.4-1
2.1 SCP and libraries
- Trim trailing spaces on all input (for example, attach file names)
- Fixed sim_sock spurious SIGPIPE error in Unix/Linux
- Fixed sim_tape misallocation of TPC map array for 64b simulators
2.2 1401
- Fixed bug, CPU reset was clearing SSB through SSG
2.3 PDP-11
- Fixed bug in VH vector display routine
- Fixed XU runt packet processing (found by Tim Chapman)
2.4 Interdata
- Fixed bug in SHOW PAS CONN/STATS
- Fixed potential integer overflow exception in divide
2.5 SDS
- Fixed bug in SHOW MUX CONN/STATS
2.6 HP
- Fixed bug in SHOW MUX CONN/STATS
2.7 PDP-8
- Fixed bug in SHOW TTIX CONN/STATS
- Fixed bug in SET/SHOW TTOXn LOG
2.8 PDP-18b
- Fixed bug in SHOW TTIX CONN/STATS
- Fixed bug in SET/SHOW TTOXn LOG
2.9 Nova, Eclipse
- Fixed potential integer overflow exception in divide
The memory layout for the Interdata simulators has been changed.
Do not use Interdata SAVE files from prior revisions with V3.4.
1. New Features in 3.4
1.1 SCP and Libraries
- Revised interpretation of fprint_sym, fparse_sym returns
- Revised syntax for SET DEBUG
- DO command nesting allowed to ten levels
1.2 Interdata
- Revised memory model to be 16b instead of 8b
1.3 HP2100
- Added Fast FORTRAN Processor instructions
- Added SET OFFLINE/ONLINE and SET UNLOAD/LOAD commands to tapes and disks
2. Bugs Fixed in 3.4-0
2.1 Interdata
- Fixed bug in show history routine (from Mark Hittinger)
- Fixed bug in initial memory allocation
2.2 PDP-10
- Fixed TU bug, ERASE and WREOF should not clear done (reported by
Rich Alderson)
- Fixed TU error reporting
2.3 PDP-11
- Fixed TU error reporting
1. New Features in 3.3-1
1.1 H316
TTY - implemented paper-tape reader and punch
- added ASCII file support
PTR,PTP - added ASCII file support
1.2 HP2100
CPU - added SET CPU 21MX-M, 21MX-E (from Dave Brian)
- disabled TIMER/EXECUTE/DIAG instructions for 21MX-M (from Dave Bryan)
- added post-processor to maintain T/M consistency (from Dave Bryan)
DS - released 13037 disk controller
1.3 Interdata
MT - added read-only file support
1.4 SDS
MT - added read-only file support
1.5 PDP-11
TM,TS - added read-only file support
2. Bugs Fixed in 3.3
2.1 H316
CPU - fixed bug in divide
LPT - fixed bug in DMA/DMC support
MT - fixed bug in DMA/DMC support
DP - fixed bug in skip on not seeking
TTY - fixed bugs in SKS '104, '504
2.2 HP2100
CPU - fixed DMA reset to clear alternate CTL flop (from Dave Bryan)
- fixed bug in JPY (from Dave Bryan)
- fixed bugs in CBS, SBS, TBS
- separate A/B from M[0/1] for DMA (found by Dave Bryan)
LPS - added restart when set online, etc. (from Dave Bryan)
- fixed col count for non-printing chars (from Dave Bryan)
LPT - added restart when set online, etc. (from Dave Bryan)
2.3 PDP-11
CPU - fixed WAIT to work in all modes (from John Dundas)
RESTRICTION: The HP DS disk is not debugged. DO NOT enable this
feature for normal operations.
WARNING: Massive changes in the PDP-11 make all previous SAVEd
file obsolete. Do not attempt to use a PDP-11 SAVE file from a
prior release with V3.3!
1. New Features in 3.3
1.1 SCP
- Added -p (powerup) qualifier to RESET
- Changed SET <unit> ONLINE/OFFLINE to SET <unit> ENABLED/DISABLED
- Moved SET DEBUG under SET CONSOLE hierarchy
- Added optional parameter value to SHOW command
- Added output file option to SHOW command
1.2 PDP-11
- Separated RH Massbus adapter from RP controller
- Added TU tape support
- Added model emulation framework
- Added model details
1.3 VAX
- Separated out CVAX-specific features from core instruction simulator
- Implemented capability for CIS, octaword, compatibility mode instructions
- Added instruction display and parse for compatibility mode
- Changed SET CPU VIRTUAL=n to SHOW CPU VIRTUAL=n
- Added =n optional parameter to SHOW CPU HISTORY
1.4 Unibus/Qbus simulators (PDP-11, VAX, PDP-10)
- Simplified DMA API's
- Modified DMA peripherals to use simplified API's
1.5 HP2100 (all changes from Dave Bryan)
CPU - moved MP into its own device; added MP option jumpers
- modified DMA to allow disabling
- modified SET CPU 2100/2116 to truncate memory > 32K
- added -F switch to SET CPU to force memory truncation
- modified WRU to be REG_HRO
- added BRK and DEL to save console settings
DR - provided protected tracks and "Writing Enabled" status bit
- added "parity error" status return on writes for 12606
- added track origin test for 12606
- added SCP test for 12606
- added "Sector Flag" status bit
- added "Read Inhibit" status bit for 12606
- added TRACKPROT modifier
LPS - added SET OFFLINE/ONLINE, POWEROFF/POWERON
- added fast/realistic timing
- added debug printouts
LPT - added SET OFFLINE/ONLINE, POWEROFF/POWERON
PTR - added paper tape loop mode, DIAG/READER modifiers to PTR
- added PV_LEFT to PTR TRLLIM register
CLK - modified CLK to permit disable
1.6 IBM 1401, IBM 1620, Interdata 16b, SDS 940, PDP-10
- Added instruction history
1.7 H316, PDP-15, PDP-8
- Added =n optional value to SHOW CPU HISTORY
2. Bugs Fixed in 3.3
2.1 SCP
- Fixed comma-separated SET options (from Dave Bryan)
- Fixed duplicate HELP displays with user-specified commands
2.2 PDP-10
- Replicated RP register state per drive
- Fixed TU to set FCE on short record
- Fixed TU to return bit<15> in drive type
- Fixed TU format specification, 1:0 are don't cares
- Fixed TU handling of TMK status
- Fixed TU handling of DONE, ATA at end of operation
- Implemented TU write check
2.3 PDP-11
- Replicated RP register state per drive
- Fixed RQ, TQ to report correct controller type and stage 1 configuration
flags on a Unibus system
- Fixed HK CS2<output_ready> flag
2.4 VAX
- Fixed parsing of indirect displacement modes in instruction input
2.5 HP2100 (all fixes from Dave Bryan)
CPU - fixed S-register behavior on 2116
- fixed LIx/MIx behavior for DMA on 2116 and 2100
- fixed LIx/MIx behavior for empty I/O card slots
DP - fixed enable/disable from either device
- fixed ANY ERROR status for 12557A interface
- fixed unattached drive status for 12557A interface
- status cmd without prior STC DC now completes (12557A)
- OTA/OTB CC on 13210A interface also does CLC CC
- fixed RAR model
- fixed seek check on 13210 if sector out of range
DQ - fixed enable/disable from either device
- shortened xtime from 5 to 3 (drive avg 156KW/second)
- fixed not ready/any error status
- fixed RAR model
DR - fixed enable/disable from either device
- fixed sector return in status word
- fixed DMA last word write, incomplete sector fill value
- fixed 12610 SFC operation
- fixed current-sector determination
IPL - fixed enable/disable from either device
LPS - fixed status returns for error conditions
- fixed handling of non-printing characters
- fixed handling of characters after column 80
- improved timing model accuracy for RTE
LPT - fixed status returns for error conditions
- fixed TOF handling so form remains on line 0
SYS - fixed display of CCA/CCB/CCE instructions
2.5 PDP-15
FPP - fixed URFST to mask low 9b of fraction
- fixed exception PC setting
RESTRICTION: The PDP-15 FPP is only partially debugged. Do NOT
enable this feature for normal operations.
1. New Features in 3.2-1
1.1 SCP and libraries
- Added SET CONSOLE subhierarchy.
- Added SHOW CONSOLE subhierarchy.
- Added limited keyboard mapping capability.
1.2 HP2100 (new features from Dave Bryan)
- Added instruction printout to HALT message.
- Added M and T internal registers.
- Added N, S, and U breakpoints.
1.3 PDP-11 and VAX
- Added DHQ11 support (from John Dundas)
2. Bugs Fixed in 3.2-1
2.1 HP2100 (most fixes from Dave Bryan)
- SBT increments B after store.
- DMS console map must check dms_enb.
- SFS x,C and SFC x,C work.
- MP violation clears automatically on interrupt.
- SFS/SFC 5 is not gated by protection enabled.
- DMS enable does not disable mem prot checks.
- DMS status inconsistent at simulator halt.
- Examine/deposit are checking wrong addresses.
- Physical addresses are 20b not 15b.
- Revised DMS to use memory rather than internal format.
- Revised IBL facility to conform to microcode.
- Added DMA EDT I/O pseudo-opcode.
- Separated DMA SRQ (service request) from FLG.
- Revised peripherals to make SFS x,C and SFC x,C work.
- Revised boot ROMs to use IBL facility.
- Revised IBL treatment of SR to preserve SR<5:3>.
- Fixed LPS, LPT timing.
- Fixed DP boot interpretation of SR<0>.
- Revised DR boot code to use IBL algorithm.
- Fixed TTY input behavior during typeout for RTE-IV.
- Suppressed nulls on TTY output for RTE-IV.
- Added SFS x,C and SFC x,C to print/parse routines.
- Fixed spurious timing error in magtape reads.
2.2 All DEC console devices
- Removed SET TTI CTRL-C option.
2.3 PDP-11/VAX peripherals
- Fixed bug in TQ reporting write protect status (reported by Lyle Bickley).
- Fixed TK70 model number and media ID (found by Robert Schaffrath).
- Fixed bug in autoconfigure (found by John Dundas).
2.4 VAX
- Fixed bug in DIVBx and DIVWx (reported by Peter Trimmel).
RESTRICTION: The PDP-15 FPP is only partially debugged. Do NOT
enable this feature for normal operations.
WARNING: The core simulator files (scp.c, sim_*.c) have been
reorganized. Unzip V3.2-0 to an empty directory before attempting
to compile the source.
IMPORTANT: If you are compiling for UNIX, please read the notes
for Ethernet very carefully. You may need to download a new
version of the pcap library, or make changes to the makefile,
to get Ethernet support to work.
1. New Features in 3.2-0
1.1 SCP and libraries
- Added SHOW <device> RADIX command.
- Added SHOW <device> MODIFIERS command.
- Added SHOW <device> NAMES command.
- Added SET/SHOW <device> DEBUG command.
- Added sim_vm_parse_addr and sim_vm_fprint_addr optional interfaces.
- Added REG_VMAD flag.
- Split SCP into separate libraries for easier modification.
- Added more room to the device and unit flag fields.
- Changed terminal multiplexor library to support unlimited.
number of async lines.
1.2 All DECtapes
- Added STOP_EOR flag to enable end-of-reel error stop
- Added device debug support.
1.3 Nova and Eclipse
- Added QTY and ALM multiplexors (Bruce Ray).
1.4 LGP-30
- Added LGP-30/LGP-21 simulator.
1.5 PDP-11
- Added format, address increment inhibit, transfer overrun
detection to RK.
- Added device debug support to HK, RP, TM, TQ, TS.
- Added DEUNA/DELUA (XU) support (Dave Hittner).
- Add DZ per-line logging.
1.6 18b PDP's
- Added support for 1-4 (PDP-9)/1-16 (PDP-15) additional
terminals.
1.7 PDP-10
- Added DEUNA/DELUA (XU) support (Dave Hittner).
1.8 VAX
- Added extended memory to 512MB (Mark Pizzolato).
- Added RXV21 support.
2. Bugs Fixed in 3.2-0
2.1 SCP
- Fixed double logging of SHOW BREAK (found by Mark Pizzolato).
- Fixed implementation of REG_VMIO.
2.2 Nova and Eclipse
- Fixed device enable/disable support (found by Bruce Ray).
2.3 PDP-1
- Fixed bug in LOAD (found by Mark Crispin).
2.4 PDP-10
- Fixed bug in floating point unpack.
- Fixed bug in FIXR (found by Phil Stone, fixed by Chris Smith).
2.6 PDP-11
- Fixed bug in RQ interrupt control (found by Tom Evans).
2.6 PDP-18B
- Fixed bug in PDP-15 XVM g_mode implementation.
- Fixed bug in PDP-15 indexed address calculation.
- Fixed bug in PDP-15 autoindexed address calculation.
- Fixed bugs in FPP-15 instruction decode.
- Fixed clock response to CAF.
- Fixed bug in hardware read-in mode bootstrap.
- Fixed PDP-15 XVM instruction decoding errors.
2.7 VAX
- Fixed PC read fault in EXTxV.
- Fixed PC write fault in INSV.
Because some key files have changed, V3.0 should be unzipped to a
clean directory.
1. New Features in 3.0-0
1.1 SCP and Libraries
- Added ASSIGN/DEASSIGN (logical name) commands.
- Changed RESTORE to unconditionally detach files.
- Added E11 and TPC format support to magtape library.
- Fixed bug in SHOW CONNECTIONS.
- Added USE_ADDR64 support
1.2 All magtapes
- Magtapes support SIMH format, E11 format, and TPC format (read only).
- SET <tape_unit> FORMAT=format sets the specified tape unit's format.
- SHOW <tape_unit> FORMAT displays the specified tape unit's format.
- Tape format can also be set as part of the ATTACH command, using
the -F switch.
1.3 VAX
- VAX can be compiled without USE_INT64.
- If compiled with USE_INT64 and USE_ADDR64, RQ and TQ controllers support
files > 2GB.
- VAX ROM has speed control (SET ROM DELAY/NODELAY).
2. Bugs Fixed in 3.01-0
2.1 VAX
- Fixed CVTfi bug: integer overflow not set if exponent out of range
- Fixed EMODx bugs:
o First and second operands reversed
o Separated fraction received wrong exponent
o Overflow calculation on separated integer incorrect
o Fraction not set to zero if exponent out of range
- Fixed interval timer and ROM access to pass power-up self-test even on very
fast host processors (fixes from Mark Pizzolato).
2.2 1401
- Fixed mnemonic, instruction lengths, and reverse scan length check bug for MCS.
- Fixed MCE bug, BS off by 1 if zero suppress.
- Fixed chaining bug, D lost if return to SCP.
- Fixed H branch, branch occurs after continue.
- Added check for invalid 8 character MCW, LCA.
- Fixed magtape load-mode end of record response.
2.3 Nova
- Fixed DSK variable size interaction with restore.
2.4 PDP-1
- Fixed DT variable size interaction with restore.
2.5 PDP-11
- Fixed DT variable size interaction with restore.
- Fixed bug in MMR1 update (found by Tim Stark).
- Added XQ features and fixed bugs:
o Corrected XQ interrupts on IE state transition (code by Tom Evans).
o Added XQ interrupt clear on soft reset.
o Removed XQ interrupt when setting XL or RL (multiple people).
o Added SET/SHOW XQ STATS.
o Added SHOW XQ FILTERS.
o Added ability to split received packet into multiple buffers.
o Added explicit runt and giant packet processing.
2.6 PDP-18B
- Fixed DT, RF variable size interaction with restore.
- Fixed MT bug in MTTR.
2.7 PDP-8
- Fixed DT, DF, RF, RX variable size interaction with restore.
- Fixed MT bug in SKTR.
2.8 HP2100
- Fixed bug in DP (13210A controller only), DQ read status.
- Fixed bug in DP, DQ seek complete.
2.9 GRI
- Fixed bug in SC queue pointer management.
3. New Features in 3.0 vs prior releases
N/A
4. Bugs Fixed in 3.0 vs prior releases
N/A
5. General Notes
WARNING: The RESTORE command has changed. RESTORE will now
detach an attached file on a unit, if that unit did not have
an attached file in the saved configuration. This is required
to assure that the unit flags and the file state are consistent.
WARNING: The compilation scheme for the PDP-10, PDP-11, and VAX
has changed. Use one of the supplied build files, or read the
documentation carefully, before compiling any of these simulators.
1. New Features in 2.10-2
The build procedures have changed. There is only one UNIX makefile.
To compile without Ethernet support, simply type
gmake {target|all}
To compile with Ethernet support, type
gmake USE_NETWORK=1 {target|all}
The Mingw batch files require Mingw release 2 and invoke the Unix
makefile. There are still separate batch files for compilation
with or without Ethernet support.
1.1 SCP and Libraries
- The EVAL command will evaluate a symbolic type-in and display
it in numeric form.
- The ! command (with no arguments) will launch the host operating
system command shell. The ! command (with an argument) executes
the argument as a host operating system command. (Code from
Mark Pizzolato)
- Telnet sessions now recognize BREAK. How a BREAK is transmitted
dependent on the particular Telnet client. (Code from Mark
Pizzolato)
- The sockets library includes code for active connections as
well as listening connections.
- The RESTORE command will restore saved memory size, if the
simulator supports dynamic memory resizing.
1.2 PDP-1
- The PDP-1 supports the Type 24 serial drum (based on recently
discovered documents).
1.3 18b PDP's
- The PDP-4 supports the Type 24 serial drum (based on recently
discovered documents).
1.4 PDP-11
- The PDP-11 implements a stub DEUNA/DELUA (XU). The real XU
module will be included in a later release.
1.5 PDP-10
- The PDP-10 implements a stub DEUNA/DELUA (XU). The real XU
module will be included in a later release.
1.6 HP 2100
- The IOP microinstruction set is supported for the 21MX as well
as the 2100.
- The HP2100 supports the Access Interprocessor Link (IPL).
1.7 VAX
- If the VAX console is attached to a Telnet session, BREAK is
interpreted as console halt.
- The SET/SHOW HISTORY commands enable and display a history of
the most recently executed instructions. (Code from Mark
Pizzolato)
1.8 Terminals Multiplexors
- BREAK detection was added to the HP, DEC, and Interdata terminal
multiplexors.
1.9 Interdata 16b and 32b
- First release. UNIX is not yet working.
1.10 SDS 940
- First release.
2. Bugs Fixed in 2.10-2
- PDP-11 console must default to 7b for early UNIX compatibility.
- PDP-11/VAX TMSCP emulator was using the wrong packet length for
read/write end packets.
- Telnet IAC+IAC processing was fixed, both for input and output
(found by Mark Pizzolato).
- PDP-11/VAX Ethernet setting flag bits wrong for chained
descriptors (found by Mark Pizzolato).
3. New Features in 2.10 vs prior releases
3.1 SCP and Libraries
- The VT emulation package has been replaced by the capability
to remote the console to a Telnet session. Telnet clients
typically have more complete and robust VT100 emulation.
- Simulated devices may now have statically allocated buffers,
in addition to dynamically allocated buffers or disk-based
data stores.
- The DO command now takes substitutable arguments (max 9).
In command files, %n represents substitutable argument n.
- The initial command line is now interpreted as the command
name and substitutable arguments for a DO command. This is
backward compatible to prior versions.
- The initial command line parses switches. -Q is interpreted
as quiet mode; informational messages are suppressed.
- The HELP command now takes an optional argument. HELP <cmd>
types help on the specified command.
- Hooks have been added for implementing GUI-based consoles,
as well as simulator-specific command extensions. A few
internal data structures and definitions have changed.
- Two new routines (tmxr_open_master, tmxr_close_master) have
been added to sim_tmxr.c. The calling sequence for
sim_accept_conn has been changed in sim_sock.c.
- The calling sequence for the VM boot routine has been modified
to add an additional parameter.
- SAVE now saves, and GET now restores, controller and unit flags.
- Library sim_ether.c has been added for Ethernet support.
3.2 VAX
- Non-volatile RAM (NVR) can behave either like a memory or like
a disk-based peripheral. If unattached, it behaves like memory
and is saved and restored by SAVE and RESTORE, respectively.
If attached, its contents are loaded from disk by ATTACH and
written back to disk at DETACH and EXIT.
- SHOW <device> VECTOR displays the device's interrupt vector.
A few devices allow the vector to be changed with SET
<device> VECTOR=nnn.
- SHOW CPU IOSPACE displays the I/O space address map.
- The TK50 (TMSCP tape) has been added.
- The DEQNA/DELQA (Qbus Ethernet controllers) have been added.
- Autoconfiguration support has been added.
- The paper tape reader has been removed from vax_stddev.c and
now references a common implementation file, dec_pt.h.
- Examine and deposit switches now work on all devices, not just
the CPU.
- Device address conflicts are not detected until simulation starts.
3.3 PDP-11
- SHOW <device> VECTOR displays the device's interrupt vector.
Most devices allow the vector to be changed with SET
<device> VECTOR=nnn.
- SHOW CPU IOSPACE displays the I/O space address map.
- The TK50 (TMSCP tape), RK611/RK06/RK07 (cartridge disk),
RX211 (double density floppy), and KW11P programmable clock
have been added.
- The DEQNA/DELQA (Qbus Ethernet controllers) have been added.
- Autoconfiguration support has been added.
- The paper tape reader has been removed from pdp11_stddev.c and
now references a common implementation file, dec_pt.h.
- Device bootstraps now use the actual CSR specified by the
SET ADDRESS command, rather than just the default CSR. Note
that PDP-11 operating systems may NOT support booting with
non-standard addresses.
- Specifying more than 256KB of memory, or changing the bus
configuration, causes all peripherals that are not compatible
with the current bus configuration to be disabled.
- Device address conflicts are not detected until simulation starts.
3.4 PDP-10
- SHOW <device> VECTOR displays the device's interrupt vector.
A few devices allow the vector to be changed with SET
<device> VECTOR=nnn.
- SHOW CPU IOSPACE displays the I/O space address map.
- The RX211 (double density floppy) has been added; it is off
by default.
- The paper tape now references a common implementation file,
dec_pt.h.
- Device address conflicts are not detected until simulation starts.
3.5 PDP-1
- DECtape (then known as MicroTape) support has been added.
- The line printer and DECtape can be disabled and enabled.
3.6 PDP-8
- The RX28 (double density floppy) has been added as an option to
the existing RX8E controller.
- SHOW <device> DEVNO displays the device's device number. Most
devices allow the device number to be changed with SET <device>
DEVNO=nnn.
- Device number conflicts are not detected until simulation starts.
3.7 IBM 1620
- The IBM 1620 simulator has been released.
3.8 AltairZ80
- A hard drive has been added for increased storage.
- Several bugs have been fixed.
3.9 HP 2100
- The 12845A has been added and made the default line printer (LPT).
The 12653A has been renamed LPS and is off by default. It also
supports the diagnostic functions needed to run the DCPC and DMS
diagnostics.
- The 12557A/13210A disk defaults to the 13210A (7900/7901).
- The 12559A magtape is off by default.
- New CPU options (EAU/NOEAU) enable/disable the extended arithmetic
instructions for the 2116. These instructions are standard on
the 2100 and 21MX.
- New CPU options (MPR/NOMPR) enable/disable memory protect for the
2100 and 21MX.
- New CPU options (DMS/NODMS) enable/disable the dynamic mapping
instructions for the 21MX.
- The 12539 timebase generator autocalibrates.
3.10 Simulated Magtapes
- Simulated magtapes recognize end of file and the marker
0xFFFFFFFF as end of medium. Only the TMSCP tape simulator
can generate an end of medium marker.
- The error handling in simulated magtapes was overhauled to be
consistent through all simulators.
3.11 Simulated DECtapes
- Added support for RT11 image file format (256 x 16b) to DECtapes.
4. Bugs Fixed in 2.10 vs prior releases
- TS11/TSV05 was not simulating the XS0_MOT bit, causing failures
under VMS. In addition, two of the CTL options were coded
interchanged.
- IBM 1401 tape was not setting a word mark under group mark for
load mode reads. This caused the diagnostics to crash.
- SCP bugs in ssh_break and set_logon were fixed (found by Dave
Hittner).
- Numerous bugs in the HP 2100 extended arithmetic, floating point,
21MX, DMS, and IOP instructions were fixed. Bugs were also fixed
in the memory protect and DMS functions. The moving head disks
(DP, DQ) were revised to simulate the hardware more accurately.
Missing functions in DQ (address skip, read address) were added.
- PDP-10 tape wouldn't boot, and then wouldn't read (reported by
Michael Thompson and Harris Newman, respectively)
- PDP-1 typewriter is half duplex, with only one shift state for
both input and output (found by Derek Peschel)
5. General Notes
WARNING: V2.10 has reorganized and renamed some of the definition
files for the PDP-10, PDP-11, and VAX. Be sure to delete all
previous source files before you unpack the Zip archive, or
unpack it into a new directory structure.
WARNING: V2.10 has a new, more comprehensive save file format.
Restoring save files from previous releases will cause 'invalid
register' errors and loss of CPU option flags, device enable/
disable flags, unit online/offline flags, and unit writelock
flags.
WARNING: If you are using Visual Studio .NET through the IDE,
be sure to turn off the /Wp64 flag in the project settings, or
dozens of spurious errors will be generated.
WARNING: Compiling Ethernet support under Windows requires
extra steps; see the Ethernet readme file. Ethernet support is
currently available only for Windows, Linux, NetBSD, and OpenBSD.
WARNING: V2.10 has reorganized and renamed some of the definition
files for the PDP-10, PDP-11, and VAX. Be sure to delete all
previous source files before you unpack the Zip archive, or
unpack it into a new directory structure.
WARNING: V2.10 has a new, more comprehensive save file format.
Restoring save files from previous releases will cause 'invalid
register' errors and loss of CPU option flags, device enable/
disable flags, unit online/offline flags, and unit writelock
flags.
WARNING: If you are using Visual Studio .NET through the IDE,
be sure to turn off the /Wp64 flag in the project settings, or
dozens of spurious errors will be generated.
WARNING: Compiling Ethernet support under Windows requires
extra steps; see the Ethernet readme file. Ethernet support is
currently available only for Windows, Linux, NetBSD, and OpenBSD.
1. New Features
1.1 SCP and Libraries
- The VT emulation package has been replaced by the capability
to remote the console to a Telnet session. Telnet clients
typically have more complete and robust VT100 emulation.
- Simulated devices may now have statically allocated buffers,
in addition to dynamically allocated buffers or disk-based
data stores.
- The DO command now takes substitutable arguments (max 9).
In command files, %n represents substitutable argument n.
- The initial command line is now interpreted as the command
name and substitutable arguments for a DO command. This is
backward compatible to prior versions.
- The initial command line parses switches. -Q is interpreted
as quiet mode; informational messages are suppressed.
- The HELP command now takes an optional argument. HELP <cmd>
types help on the specified command.
- Hooks have been added for implementing GUI-based consoles,
as well as simulator-specific command extensions. A few
internal data structures and definitions have changed.
- Two new routines (tmxr_open_master, tmxr_close_master) have
been added to sim_tmxr.c. The calling sequence for
sim_accept_conn has been changed in sim_sock.c.
- The calling sequence for the VM boot routine has been modified
to add an additional parameter.
- SAVE now saves, and GET now restores, controller and unit flags.
- Library sim_ether.c has been added for Ethernet support.
1.2 VAX
- Non-volatile RAM (NVR) can behave either like a memory or like
a disk-based peripheral. If unattached, it behaves like memory
and is saved and restored by SAVE and RESTORE, respectively.
If attached, its contents are loaded from disk by ATTACH and
written back to disk at DETACH and EXIT.
- SHOW <device> VECTOR displays the device's interrupt vector.
A few devices allow the vector to be changed with SET
<device> VECTOR=nnn.
- SHOW CPU IOSPACE displays the I/O space address map.
- The TK50 (TMSCP tape) has been added.
- The DEQNA/DELQA (Qbus Ethernet controllers) have been added.
- Autoconfiguration support has been added.
- The paper tape reader has been removed from vax_stddev.c and
now references a common implementation file, dec_pt.h.
- Examine and deposit switches now work on all devices, not just
the CPU.
- Device address conflicts are not detected until simulation starts.
1.3 PDP-11
- SHOW <device> VECTOR displays the device's interrupt vector.
Most devices allow the vector to be changed with SET
<device> VECTOR=nnn.
- SHOW CPU IOSPACE displays the I/O space address map.
- The TK50 (TMSCP tape), RK611/RK06/RK07 (cartridge disk),
RX211 (double density floppy), and KW11P programmable clock
have been added.
- The DEQNA/DELQA (Qbus Ethernet controllers) have been added.
- Autoconfiguration support has been added.
- The paper tape reader has been removed from pdp11_stddev.c and
now references a common implementation file, dec_pt.h.
- Device bootstraps now use the actual CSR specified by the
SET ADDRESS command, rather than just the default CSR. Note
that PDP-11 operating systems may NOT support booting with
non-standard addresses.
- Specifying more than 256KB of memory, or changing the bus
configuration, causes all peripherals that are not compatible
with the current bus configuration to be disabled.
- Device address conflicts are not detected until simulation starts.
1.4 PDP-10
- SHOW <device> VECTOR displays the device's interrupt vector.
A few devices allow the vector to be changed with SET
<device> VECTOR=nnn.
- SHOW CPU IOSPACE displays the I/O space address map.
- The RX211 (double density floppy) has been added; it is off
by default.
- The paper tape now references a common implementation file,
dec_pt.h.
- Device address conflicts are not detected until simulation starts.
1.5 PDP-1
- DECtape (then known as MicroTape) support has been added.
- The line printer and DECtape can be disabled and enabled.
1.6 PDP-8
- The RX28 (double density floppy) has been added as an option to
the existing RX8E controller.
- SHOW <device> DEVNO displays the device's device number. Most
devices allow the device number to be changed with SET <device>
DEVNO=nnn.
- Device number conflicts are not detected until simulation starts.
1.7 IBM 1620
- The IBM 1620 simulator has been released.
1.8 AltairZ80
- A hard drive has been added for increased storage.
- Several bugs have been fixed.
1.9 HP 2100
- The 12845A has been added and made the default line printer (LPT).
The 12653A has been renamed LPS and is off by default. It also
supports the diagnostic functions needed to run the DCPC and DMS
diagnostics.
- The 12557A/13210A disk defaults to the 13210A (7900/7901).
- The 12559A magtape is off by default.
- New CPU options (EAU/NOEAU) enable/disable the extended arithmetic
instructions for the 2116. These instructions are standard on
the 2100 and 21MX.
- New CPU options (MPR/NOMPR) enable/disable memory protect for the
2100 and 21MX.
- New CPU options (DMS/NODMS) enable/disable the dynamic mapping
instructions for the 21MX.
- The 12539 timebase generator autocalibrates.
1.10 Simulated Magtapes
- Simulated magtapes recognize end of file and the marker
0xFFFFFFFF as end of medium. Only the TMSCP tape simulator
can generate an end of medium marker.
- The error handling in simulated magtapes was overhauled to be
consistent through all simulators.
1.11 Simulated DECtapes
- Added support for RT11 image file format (256 x 16b) to DECtapes.
2. Release Notes
2.1 Bugs Fixed
- TS11/TSV05 was not simulating the XS0_MOT bit, causing failures
under VMS. In addition, two of the CTL options were coded
interchanged.
- IBM 1401 tape was not setting a word mark under group mark for
load mode reads. This caused the diagnostics to crash.
- SCP bugs in ssh_break and set_logon were fixed (found by Dave
Hittner).
- Numerous bugs in the HP 2100 extended arithmetic, floating point,
21MX, DMS, and IOP instructions were fixed. Bugs were also fixed
in the memory protect and DMS functions. The moving head disks
(DP, DQ) were revised to simulate the hardware more accurately.
Missing functions in DQ (address skip, read address) were added.
2.2 HP 2100 Debugging
- The HP 2100 CPU nows runs all of the CPU diagnostics.
- The peripherals run most of the peripheral diagnostics. There
is still a problem in overlapped seek operation on the disks.
See the file hp2100_diag.txt for details.
3. In Progress
These simulators are not finished and are available in a separate
Zip archive distribution.
- Interdata 16b/32b: coded, partially tested. See the file
id_diag.txt for details.
- SDS 940: coded, partially tested.
1. New Features
1.1 GRI-909
- This is a new simulator for the GRI-909.
- It has been hand-tested; so far, no software has been discovered.
1.2 VAX
- SET CPU CONHALT will cause a HALT instruction to return to the
boot ROM console rather than to SIMH. SET CPU SIMHALT restores
the default behavior.
- BRB/W self at IPL 1F stops the simulator. This is the default
behavior of VMS at exit.
1.3 PDP-18b
- ATTACH -A PTR/PTP attaches the reader and punch in ASCII mode.
In ASCII mode, the reader automatically sets the high order bit
of incoming alphabetic data, and the punch clears the high order
bit of outgoing data.
1.4 SCP
- DO -V echoes commands from the file as they are executed.
- Under Windows, execution priority is set BELOW_NORMAL when the
simulator is running.
2. Release Notes
2.1 Bugs Fixed
- PDP-11 CPU: fixed updating of MMR0 on a memory management error.
- VAX FPA: changed function names to avoid conflict with C math library.
- 1401 MT: read end of record generates group mark without word mark.
- 1401 DP: fixed address generation and checking.
- SCP: an EXIT within a DO command will cause the simulator to exit.
3. In Progress
- Interdata 16b/32b: coded, not tested.
- SDS 940: coded, not tested.
- IBM 1620: coded, not tested.
If you would like to help with the debugging of the untested simulators,
they can be made available by special request.
1. New Features
1.1 Directory and documentation
- Only common files (SCP and libraries) are in the top level
directory. Individual simulator files are in their individual
directories.
- simh_doc.txt has been split up. simh_doc.txt now documents
only SCP. The individual simulators are documented in separate
text files in their own directories.
- mingw_build.bat is a batch file for the MINGW/gcc environment
that will build all the simulators, assuming the root directory
structure is at c:\sim.
- Makefile is a UNIX make file for the gcc environment that will
build all the simulators, assuming the root directory is at
c:\sim.
1.2 SCP
- DO <file name> executes the SCP commands in the specified file.
- Replicated registers in unit structures can now be declared as
arrays for examine, modify, save, and restore. Most replicated
unit registers (for example, mag tape position registers) have
been changed to arrays.
- The ADD/REMOVE commands have been replaced by SET unit ONLINE
and SET unit OFFLINE, respectively.
- Register names that are unique within an entire simulator do
not have to be prefaced with the device name.
- The ATTACH command can attach files read only, either under
user option (-r), or because the attached file is ready only.
- The SET/SHOW capabilities have been extended. New forms include:
SET <dev> param{=value}{ param ...}
SET <unit> param{=value}{ param ...}
SHOW <dev> {param param ...}
SHOW <unit> {param param ...}
- Multiple breakpoints have been implemented. Breakpoints are
set/cleared/displayed by:
BREAK addr_list{[count]}
NOBREAK addr_list
SHOW BREAK addr_list
1.3 PDP-11 simulator
- Unibus map implemented, with 22b RP controller (URH70) or 18b
RP controller (URH11) (in debug).
- All DMA peripherals rewritten to use map.
- Many peripherals modified for source sharing with VAX.
- RQDX3 implemented.
- Bugs fixed in RK11 and RL11 write check.
1.4 PDP-10 simulator
- ITS 1-proceed implemented.
- Bugs fixed in ITS PC sampling and LPMR
1.5 18b PDP simulator
- Interrupts split out to multiple levels to allow easier
expansion.
1.5 IBM System 3 Simulator
- Written by Charles (Dutch) Owen.
1.6 VAX Simulator (in debug)
- Simulates MicroVAX 3800 (KA655) with 16MB-64MB memory, RQDX3,
RLV12, TSV11, DZV11, LPV11, PCV11.
- CDROM capability has been added to the RQDX3, to allow testing
with VMS hobbyist images.
1.7 SDS 940 Simulator (not tested)
- Simulates SDS 940, 16K-64K memory, fixed and moving head
disk, magtape, line printer, console.
1.8 Altair Z80
- Revised from Charles (Dutch) Owen's original by Peter Schorn.
- MITS 8080 with full Z80 simulation.
- 4K and 8K BASIC packages, Prolog package.
1.9 Interdata
The I4 simulator has been withdrawn for major rework. Look for
a complete 16b/32b Interdata simulator sometime next year.
2. Release Notes
2.1 SCP
SCP now allows replicated registers in unit structures to be
modelled as arrays. All replicated register declarations have
been replaced by register array declarations. As a result,
save files from prior revisions will generate errors after
restoring main memory.
2.2 PDP-11
The Unibus map code is in debug. The map was implemented primarily
to allow source sharing with the VAX, which requires a DMA map.
DMA devices work correctly with the Unibus map disabled.
The RQDX3 simulator has run a complete RSTS/E SYSGEN, with multiple
drives, and booted the completed system from scratch.
2.3 VAX
The VAX simulator will run the boot code up to the >>> prompt. It
can successfully process a SHOW DEVICE command. It runs the HCORE
instruction diagnostic. It can boot the hobbyist CD through SYSBOOT
and through the date/time dialog and restore the hobbyist CD, using
standalone backup. On the boot of the restored disk, it gets to the
date/time dialog, and then crashes.
2.4 SDS 940
The SDS 940 is untested, awaiting real code.
2.5 GCC Optimization
At -O2 and above, GCC does not correctly compile the simulators which
use setjmp-longjmp (PDP-11, PDP-10, VAX). A working hypothesis is
that optimized state maintained in registers is being used in the
setjmp processing routine. On the PDP-11 and PDP-10, all of this
state has been either made global, or volatile, to encourage GCC to
keep the state up to date in memory. The VAX is still vulnerable.
3. Work list
3.1 SCP
- Better ENABLE/DISABLE.
3.2 PDP-11 RQDX3
Software mapped mode, RCT read simulation, VMS debug.
