HP3000/hp3000_release.txt

                           SIMH/HP 3000 RELEASE NOTES
                           ==========================
                             Last update: 2016-07-05


This file documents the release history of the Hewlett-Packard 3000 simulator.

The SIMH project does not issue discrete releases.  Instead, the current
simulator code base is available at:

  https://github.com/simh/simh

...and may be downloaded at any time.  A code snapshot is identified by the "git
commit ID" that is displayed by the simulator welcome banner.

Therefore, HP 3000 releases are simply documentation checkpoints that describe
the changes that have occurred since the last checkpoint.  Generally, a release
is written when one or more major changes have been incorporated.  Minor bug
fixes will be available immediately but only noted as part of the next release
document.



===================
General Information
===================

The simulator passes the HP 32230 offline diagnostic suite with some expected
failures due to unimplemented features.  For example, the disc diagnostic
error-correction logic tests and the tape diagnostic CRCC and LRCC tests fail,
as these features are not supported.  However, all features that are required
for MPE operation pass their respective diagnostic tests.

The simulator has been tested with MPE-V/R version E.01.00.  Specifically:

 - MPE can be RELOADed to generate a new disc-based system from a FOS tape.

 - MPE can be COOLSTARTed to run from a previously generated disc.

 - The MPE system console operates (by default) through the simulation console,
   and additional sessions may be connected to the ATC via Telnet or host
   serial ports.

 - MPE FOS programs (EDITOR, QUERY) and SUBSYS programs (SPL, BASIC, BASICOMP)
   run properly.

 - The SYSDUMP program produces a valid tape image, and the system may be
   COLDSTARTED from it.

 - The operator and system manager can be logged in and out, and MPE can be
   SHUTDOWN through to a HALT 17.

The user's manual for the simulator is provided in Microsoft Word format in the
"doc" subdirectory of the code base snapshot downloaded from the github site.  A
PDF version of the same manual is available at:

  http://alum.mit.edu/www/jdbryan/hp3000_doc.pdf

A preconfigured MPE-V/R disc image containing the Fundamental Operating Software
(FOS), selected SUBSYS language processors (BASIC, BASICOMP, COBOL, COBOLII,
FORTRAN, PASCAL, RPG, and SPL), and example programs is available from Bitsavers
at:

  http://www.bitsavers.org/bits/HP/HP_3000/

The archive contains instructions and simulator command files that allow
ready-to-run operation.

Manuals describing MPE operation are also available from Bitsavers at:

  http://www.bitsavers.org/pdf/hp/3000/

HP created MPE-V/R-specific manuals.  However, very few of them survive.  In
general, the MPE-IV manuals describe a subset of MPE-V/R commands, whereas the
MPE-V/E manuals describe a superset.  Relying on the MPE-IV manuals and the
online help available within MPE for those commands that do not appear in the
manuals is perhaps the best compromise.


-----------------------
Bugs in MPE V/R E.01.00
-----------------------

Testing during simulator development revealed the presence of several bugs in
the MPE version used:

 - After a cold load from tape (COLDSTART/RELOAD/UPDATE), if a non-HP terminal
   such as the simulation console is used as the system console, MPE prints DATE
   (M/D/Y)? and then WED, NOV  1, 1972, 12:00 AM, as though RETURN had been
   entered, but it wasn't.  If an HP terminal emulator is used instead, MPE
   waits for the user to enter the date before proceeding.

   The problem is incorrect coding in the SPEEDSENSE procedure in module
   INITIAL.  As a result, the console baud rate is set to an invalid value, so
   console reads fail.  The resulting zero-length read is interpreted as though
   RETURN had been entered.

   This is MPE V/R SSB KPR Number 5000187104, "Foreign devices as SIII system
   consoles do not work correctly on V/R."  HP issued a patch for this, but it
   does not seem to have survived.  A simple workaround is to set local ENQ/ACK
   processing on ATC channel 0 (SET ATCD0 LOCALACK) when the system console is
   not an HP terminal.  This is the default setting, so the bug only manifests
   itself when SET ATCD0 REMOTEACK is done before booting.  An alternate
   workaround that does not depend on the ATC setting is to set memory location
   01.112247 to octal value 021360.  This changes the "LOAD P+22,I,X"
   instruction at that location to "LDI 360" to set the detected speed to 2400
   baud unconditionally.


 - If a SHUTDOWN is performed while a logon read is pending on the system
   console, e.g., by pressing RETURN to obtain the colon prompt after logging
   OPERATOR.SYS off, the expected "ALL JOBS LOGGED OFF" message does not print.
   Instead, the first few characters of the message (which begins with the
   current time) are printed, followed as expected by SHUT and a HALT %17.  If
   no read is pending, either because RETURN was not pressed before entering the
   SHUTDOWN command or because the read timed out, the message is printed
   normally.

   The problem is that while the message is being send to the ATC character-by-
   character, the I/O abort issued to cancel the logon read also cancels the
   message write.  The timing is such that only the first few characters of the
   message are printed before the rest of the output is cancelled.

   No SSB KPR has been located, but a later MPE version inserts an ABORTIO call
   for the system console immediately before logging all sessions off.  This
   clears any logon read that might exist, and therefore an abort will not be
   performed after the "ALL JOBS LOGGED OFF" message is output.  It is
   impossible to patch memory to add this call, so the only workarounds when
   shutting down are to avoid requesting the logon prompt, wait until the logon
   timeout expires (nominally two minutes), log on and then back off again,
   enter "=ABORTIO 20" to abort the read before entering SHUTDOWN, or accept
   that the message will be truncated.  The only consequence of this bug is the
   partial message; MPE shuts down properly otherwise, so it may be safely
   ignored.


 - After a RELOAD, running DPAN4.PUB.SYS produces a "CODE SEGMENT TOO LARGE
   (LOAD ERR 33)" error.  This is because MPE defaults to an 8K code segment
   size limit, and DPAN4 has three segments between 8K and 12K in size.  If the
   limit is subsequently raised via a SYSDUMP and COLDSTART reconfiguration,
   running DPAN4 produces a "FILE IS NOT A VALID PROGRAM FILE" error.  However,
   if the reconfiguration is done before running DPAN4, it will run properly
   thereafter.

   The problem is that MPE incorrectly modifies the executable file's Segment
   Transfer Tables when it encounters a code segment that is larger than the
   configured limit.  This leaves the file in an inconsistent state, leading to
   the "NOT A VALID PROGRAM FILE" message after reconfiguration to raise the
   segment size limit.  If the limit is raised before running DPAN4, the file is
   internally consistent when the STTs are patched, and each segment's load
   succeeds, allowing the program to run.

   No SSB KPR has been located, but a later MPE version ensures that code
   segment size aborts occur before any of the STTs are modified, so the program
   file remains internally consistent.  A memory patch is impossible, but
   workarounds are to increase the code segment limit before running DPAN4 and
   to restore DPAN4.PUB.SYS from the FOS tape if it has been damaged.



=====================
Release 2, 2016-07-05
=====================

This release of the HP 3000 simulator adds the following device simulation:

  - 30209A Line Printer Controller with One 2607/13/17/18 Line Printer

The simulation supports the use of custom VFU tape images, as well as the
built-in HP-standard VFU tape.  The simulated device name is "LP".  The full set
of configurable options is detailed in a new section of the HP 3000 Simulator
User's Guide.

In addition, the preconfigured MPE-V/R disc image has been updated to add the
following features:

  - The MPE cold load command files attach the line printer to the "lp.txt"
    output file and specify the "-n" option to clear the file before use.

  - Preinstalled User-Defined Commands (UDCs) provide access to the COBOL 74
    compiler with the MPE-V/E :COBOLII, :COBOLIIPREP, and :COBOLIIGO commands,
    and to the COBOL 85 compiler with :COBOLIIX, :COBOLIIXPREP, and :COBOLIIXGO.
    However, see the implementation note below.


--------------------
Implementation Notes
--------------------

 - MPE requires a line printer, so it is recommended that the MPE startup
   simulator command file include an ATTACH LP <filename> command to load paper
   into the printer before cold loading.  If the printer is not attached, it
   will appear to MPE to be out of paper.

 - The line printer terminates each print line with an HP-standard CR/LF pair.
   If the output file is to be retained as a text file on a Unix system, removal
   of the carriage returns, e.g., via the "dos2unix" utility, may be desirable.

 - The simulator currently does not provide the HP 32234A COBOL II firmware
   instructions, so programs generated by the COBOLII compiler will abort at run
   time with an "ILLEGAL INSTRUCTION" error.  Programs generated by the COBOL
   compiler do not use these instructions and therefore are not affected.


----------
Bugs Fixed
----------

  1. PROBLEM:  The effective address of a byte pointer with a negative index is
     calculated incorrectly.

     VERSION:  Release 1

     OBSERVATION:  Defining a :WELCOME message in MPE appears to work, but when
     the next logon attempts to print the message, an infinite number of CRLFs
     are printed instead.

     CAUSE:  The welcome message is stored in an extra data segment.  The format
     for each message line is a line length stored in the lower byte of the word
     preceding the message string.  The code defines BYTE POINTER NEXTLINE and
     points NEXTLINE to the first message character.  The line length is set
     with NEXTLINE(-1) := IOCOUNT.  This generates a LOAD <IOCOUNT> ; LDXN 1 ;
     STB <NEXTLINE>,I,X sequence.

     In the "cpu_ea" routine, the indexing adds the X register value (-1) to the
     byte pointer (NEXTLINE).  This causes an overflow that is not masked to 16
     bits.  For a word access, this displacement is added to the base register
     and then masked to 16 bits, which gives the correct value.  However, for
     byte accesses, the displacement is divided by 2 and then added, and the sum
     is masked.  Dividing by 2 shifts the overflow bit into the MSB, causing the
     addition result to be off by 32K.  The STB goes to the wrong location, the
     original zero in the length byte location is retained, and when the welcome
     message is printed, a zero-length line is printed, and the byte pointer is
     incremented by zero, so the null line is printed forever.

     RESOLUTION:  Modify "cpu_ea" (hp3000_cpu.c) to mask indexed displacements
     to 16 bits after adding the X register value.

     STATUS:  Fixed in Release 2.


  2. PROBLEM:  An SMSK instruction may clear the interrupt mask flip-flop of a
     device that specifies that it is should be "always enabled."

     VERSION:  Release 1

     OBSERVATION:  If the TOS word is zero, an SMSK instruction will clear the
     interrupt mask flip-flop of a device whose mask jumper is set to "E"
     (always enabled).

     CAUSE:  In response to a DSETMASK signal, device interfaces set their
     interrupt mask flip-flops by "anding" the incoming data word with the
     interrupt mask jumper setting.  The jumper setting value for "always
     enabled" is %177777, which sets the mask flip-flop in all cases, except
     when the data word is zero.

     RESOLUTION:  Modify hp3000_atc.c, hp3000_ds.c, and hp3000_ms.c to set their
     mask flip-flops unconditionally if the jumper setting is "E".

     STATUS:  Fixed in Release 2.


  3. PROBLEM:  The "SET <dev> INTMASK=<n>" command sets the wrong bit in the
     device interface's interrupt mask jumper setting.

     VERSION:  Release 1

     OBSERVATION:  The interrupt mask jumper on a device interface is set by
     specifying the mask bit number in a "SET <dev> INTMASK=<n>" command.  This
     sets a bit in the device's interrupt mask jumper word corresponding to the
     bit number requested.  However, the bit numbering is incorrect; setting the
     jumper for bit 15, for example, sets bit 0 of the jumper word.  Therefore,
     the interface's mask flip-flop is not set as expected when an SMSK
     instruction is executed.

     CAUSE:  The bit numbers were counted from the wrong end of the word.

     RESOLUTION:  Modify "hp_set_dib" and "hp_show_dib" (hp3000_sys.c) to number
     the bits from the MSB instead of the LSB.

     STATUS:  Fixed in Release 2.


  4. PROBLEM:  The Multiplexer Channel is not generating the ACKSR signal
     correctly.

     VERSION:  Release 1

     OBSERVATION:  The line printer controller hangs when an SIO chained write
     is performed.  The first programmed write completes normally, but the
     second does not start.  The channel is waiting for a service request that
     does not occur.

     CAUSE:  The service request from the last write of the first block transfer
     is being cleared by an ACKSR generated by the Multiplexer Channel when it
     performs the IOCW fetch in State A for the second write request.  The
     channel should omit this ACKSR when the previous I/O order was a chained
     read or write.  However, the simulator is testing the order just fetched
     (Write) instead of the order that has just completed (Write Chained).

     RESOLUTION:  Modify "mpx_service" (hp3000_mpx.c) to test the correct I/O
     order in State A.

     STATUS:  Fixed in Release 2.



=====================
Release 1, 2016-03-07
=====================

This is the initial release of the HP 3000 simulator.  The following devices are
currently simulated:

  - 30003B Series III computer with up to 1024 KW of memory
  - 30003B I/O Processor
  - 30036B Multiplexer Channel
  - 30030C Selector Channel
  - 30033A Selector Channel Maintenance Board
  - 30032B Asynchronous Terminal Controller data interface
  - 30061B Asynchronous Terminal Controller control interface
  - 30135A System Clock/Fault Logging Interface
  - 30215A Tape Controller with four 7970B/E drives
  - 30229B Disc Controller with eight 7905/7906/7920/7925 drives

The "HP 3000 Simulator User's Guide" manual describes the configuration and
operation of each of these devices in detail.


--------------------
Implementation Notes
--------------------

 - IMPORTANT: There is no line printer simulation.  MPE cannot be configured to
   run without a printer; attempting to delete LDEV 6 produces "ERROR #115
   UNDEFINED CLASS LP USED AS OUTPUT DEVICE", and class LP cannot be deleted.
   With LDEV 6 present, MPE will boot and run, but doing, e.g., :STOPSPOOL 6
   causes "NON-RESPONDING DRT #14" and "SYSTEM FAILURE #201" when the printer
   doesn't respond.  Entering :OUTFENCE 14 at the console operator's session
   immediately after bootup is a workaround.  The LP simulator should be present
   in the next release.

 - The CPU is a hybrid of the Series II instruction set microcode and the Series
   III memory size and hardware behavior, because the Series III microcode is
   not available.

 - The CPU is currently missing a few "difficult" instructions (the CMD
   instruction, the Series II LOCK and UNLK instructions, and the entire
   Extended Instruction Set).  Although the EIS is not present, MPE has a
   software emulator for these instructions that is invoked transparently by the
   Unimplemented Instruction traps that occur when attempted execution of EIS
   instructions occurs.

 - The main memory Fault Logging Interface section of the 30135A is currently
   not simulated.  Although fault-control memory was standard on the Series II
   and later, the memory fault logger is smart enough to realize that the FLI is
   not there, so MPE will run without it.

 - Symbolic entry of CPU instructions, CPU status, and I/O instructions are not
   currently supported.