Hercules Version 3: Installation and Operation


Installation Procedure

Configuration Procedure

Creating DASD volumes

Operating Procedure

Technical Support

Installation Procedure

Building from source - Windows

  1. Download the distribution file hercules-3.13.zip
  2. (optional) If you want your executable to support compressed DASD or the Hercules Automatic Operator (HAO), also download these packages:
  3. Hercules for Windows is built using the Microsoft Visual C (MSVC) compiler. Refer to file README.WIN32 or README.WIN64 for details.

Building from source - Mac OS X

  1. Install Xcode from the App Store.
  2. Install Homebrew using the procedure described at http://brew.sh/
  3. Use these commands to install pre-requisite software:
    brew install autoconf
    brew install automake
    brew install gnu-sed
    automake --add-missing
  4. Proceed with Building from source - Linux and Mac OS X below.

Building from source - Linux and Mac OS X

  1. Download the distribution file hercules-3.13.tar.gz
    Note: By downloading this file you agree to the terms of the Q Public Licence.

  2. Use these commands to unzip the distribution file:
    tar xvzf ../hercules-3.13.tar.gz
    cd hercules-3.13
  3. Verify you have all of the correct versions of all of the required packages installed:


  4. Generate the configure script:


  5. Configure Hercules for your system:


    By default, the configure script will attempt to guess appropriate compiler optimization flags for your system. If its guesses turn out to be wrong, you can disable all optimization by passing the --disable-optimization option to configure, or specify your own optimization flags with --enable-optimization=FLAGS

    For additional configuration options, run: ./configure --help

  6. Build the executables:


  7. Install the programs: as root:

    make install

Important: You must use at least version 3.00 of the gcc compiler and the glibc2 library. Refer to the Hercules Frequently-Asked Questions page for required compiler and other software levels.

Installing pre-built binaries for Mac OS X:

Homebrew may be used to install Hercules on a Mac with an Intel processor and OS X 10.5 or above.

  1. Homebrew requires Xcode which can be installed from the App Store.
  2. Install Homebrew using the procedure described at http://brew.sh/
  3. Enter these commands at a terminal prompt:
    brew help
    brew doctor
    brew install hercules

Installing pre-built binaries for Windows:

  1. Download one of the following packages
  2. You may also want to install Fish's Hercules GUI for Windows. You can get it from http://www.softdevlabs.com/Hercules/hercgui-index.html.

Configuration Procedure

You will need to amend the configuration file hercules.cnf to reflect your device layout and intended mode of operation (S/370, ESA/390, or z/Architecture). See the Hercules Configuration File page for a complete description.

Creating DASD volumes

The Creating Hercules DASD page describes various methods of creating and loading virtual DASD volumes. The compressed CKD DASD support is described in this page.

Operating Procedure

Note: If you intend to run any licensed software on your PC using Hercules, it is your responsibility to ensure that you do not violate the software vendor's licensing terms.

Starting Hercules

To start Hercules enter this command at the Unix or Windows command prompt:

    hercules  [ -f filename ]
              [ -d ]
              [ -p dyndir ]  [[-l dynmod ] ... ]
              [ > logfile ]



is the name of the configuration file. The default, if none is specified, is hercules.cnf. The default may be overridden via the HERCULES_CNF environment variable.


specifies that Hercules is to be run in 'daemon' mode, wherein it runs invisibly with no attached console.


is the directory from which dynamic modules are to be loaded. The default depends on the host platform on which Hercules is being run. This option overrides the default.


is the name of an additional dynamic module to be loaded at startup. More than one additional module may be specified, although each must be preceded with the -l option specifier.


is an optional log file which will receive a copy of all messages displayed on the control panel

Next connect a tn3270 client to the console port (normally port 3270). The client will be connected to the first 3270 device address specified in the configuration file (this should be the master console address). If your master console is a 1052 or 3215, connect a telnet client instead of a tn3270 client.

Now you can enter an ipl command from the control panel.

Using the keyboard

The main Hercules screen contains a scrollable list of messages with a command input area and system status line at the bottom of the screen.

To scroll through the messages, use either the Page Up or Page Down keys, the Ctrl + Up Arrow or Ctrl + Down Arrow keys, or the Home or End and/or the Ctrl + Home or Ctrl + End keys.

Important messages are highlighted in a different color (usually red) and are prevented from being scrolled off the screen for two minutes. If Extended Cursor handling is available then important messages currently at the top of the screen can be removed early by moving the cursor to the line containing the message and then pressing enter.

Use the Insert key to switch between insert and overlay mode when typing in the command input area. Use the Home and End keys to move to the first or last character of the command you are typing, or the use the left/right arrow keys to move to a specific character. Use the Escape key to erase the input area.

Pressing Escape when the command input area is already empty causes the screen to switch to the semi-graphical "New Panel" display mode, which shows the overall status of the system and devices.

When in the semi-graphical "New Panel" display mode there is no command input area. Instead, single character "hot keys" are used to issue some of the more common functions such as starting or stopping the CPU. The hot-keys are those which are highlighted. Pressing the '?' key displays brief help information on how to use the semi-graphical panel.

Normal cursor handling
Key Action
Esc Erases the contents of the command input area. If the command input area is already empty, switches to semi-graphical New Panel.
Del Deletes the character at the cursor position.
Backspace Erases the previous character.
Insert Toggles between insert mode and overlay mode.
Tab Attempts to complete the partial file name at the cursor position in the command input area. If more than one possible file exists, a list of matching file names is displayed.
Home Moves the cursor to the start of the input in the command input area. If the command input area is empty, scrolls the message area to the top.
End Moves the cursor to the end of the input in the command input area. If the command input area is empty, scrolls the message area to the bottom.
Page Up Scrolls the message area up one screen.
Page Down Scrolls the message area down one screen.
Up arrow Recalls previous command into the input area.
Down arrow Recalls next command into the input area.
Right arrow Moves cursor to next character of input area.
Left arrow Moves cursor to previous character of input area.
Ctrl + Up arrow Scrolls the message area up one line.
Ctrl + Down arrow Scrolls the message area down one line.
Ctrl + Home Scrolls the message area to the top.
Ctrl + End Scrolls the message area to the bottom.

The following additional keyboard functions are effective when the Hercules Extended Cursor Handling feature (OPTION_EXTCURS) is activated at compile time. At present, this feature is activated on the Windows platform only.

Extended cursor handling
Key Action
Alt + Up arrow Moves cursor up one row.
Alt + Down arrow Moves cursor down one row.
Alt + Right arrow Moves cursor right one column.
Alt + Left arrow Moves cursor left one column.
Tab If cursor is outside the command input area, moves cursor to the start of the input in the command input area. Otherwise behaves as described in previous table.
Home If cursor is outside the command input area, moves cursor to the start of the input in the command input area. Otherwise behaves as described in previous table.
End If cursor is outside the command input area, moves cursor to the end of the input in the command input area. Otherwise behaves as described in previous table.

Panel commands

The following is what is displayed on the Hercules harware console (HMC) in response to the '?' command being entered. Please note that it may not be completely accurate or up-to-date. Please enter the '?' command for yourself for a more complete, accurate and up-to-date list of supported panel commands.

  Command      Description...
  -------      -----------------------------------------------
  ?            list all commands
  help         command specific help

  *            (log comment to syslog)

  message      display message on console a la VM
  msg          same as message
  msgnoh       same as message - no header

  hst          history of commands
  hao          Hercules Automatic Operator
  log          direct log output
  logopt       change log options
  version      display version information

  quit         terminate the emulator
  exit         (synonym for 'quit')

  cpu          define target cpu for panel display and commands

  start        start CPU (or printer device if argument given)
  stop         stop CPU (or printer device if argument given)

  startall     start all CPU's
  stopall      stop all CPU's

  cf           configure current CPU online or offline
  cfall        configure all CPU's online or offline

  .reply       scp command
  !message     scp priority messsage
  ssd          Signal Shutdown

  ptt          display pthread trace

  i            generate I/O attention interrupt for device
  ext          generate external interrupt
  restart      generate restart interrupt
  archmode     set architecture mode
  loadparm     set IPL parameter

  ipl          IPL Normal from device xxxx
  iplc         IPL Clear from device xxxx
  sysreset     Issue SYSTEM Reset manual operation
  sysclear     Issue SYSTEM Clear Reset manual operation
  store        store CPU status at absolute zero

  psw          display or alter program status word
  gpr          display or alter general purpose registers
  fpr          display floating point registers
  fpc          display floating point control register
  cr           display or alter control registers
  ar           display access registers
  pr           display prefix register
  timerint     display or set timers update interval
  clocks       display tod clkc and cpu timer
  ipending     display pending interrupts
  ds           display subchannel
  r            display or alter real storage
  v            display or alter virtual storage
  u            disassemble storage
  devtmax      display or set max device threads
  k            display cckd internal trace

  attach       configure device
  detach       remove device
  define       rename device
  devinit      reinitialize device
  devlist      list device or all devices

  qd           query dasd

  automount    show/update allowable tape automount directories

  scsimount    automatic SCSI tape mounts

  cd           change directory
  pwd          print working directory
  sh           shell command

  cache        cache command
  cckd         cckd command
  shrd         shrd command
  conkpalv     display/alter console TCP keep-alive settings
  quiet        toggle automatic refresh of panel display data

  t            instruction trace
  t+           instruction trace on
  t-           instruction trace off
  t?           instruction trace query
  s            instruction stepping
  s+           instruction stepping on
  s-           instruction stepping off
  s?           instruction stepping query
  b            set breakpoint
  b+           set breakpoint
  b-           delete breakpoint
  g            turn off instruction stepping and start CPU

  ostailor     trace program interrupts
  pgmtrace     trace program interrupts
  savecore     save a core image to file
  loadcore     load a core image file
  loadtext     load a text deck file

  ldmod        load a module
  rmmod        delete a module
  lsmod        list dynamic modules
  lsdep        list module dependencies

  iodelay      display or set I/O delay value
  ctc          enable/disable CTC debugging
  toddrag      display or set TOD clock drag factor
  panrate      display or set rate at which console refreshes
  msghld       display or set the timeout of held messages
  syncio       display syncio devices statistics
  maxrates     display maximum observed MIPS/SIOS rate for the
               defined interval or define a new reporting interval

  defsym       Define symbol
  script       Run a sequence of panel commands contained in a file
  cscript      Cancels a running script thread

  evm          ECPS:VM Commands (Deprecated)
  ecpsvm       ECPS:VM Commands

  aea          Display AEA tables
  aia          Display AIA fields
  tlb          Display TLB tables

  sizeof       Display size of structures

  suspend      Suspend hercules
  resume       Resume hercules

  herclogo     Read a new hercules logo file

  traceopt     Instruction trace display options

  cmdtgt       Specify the command target

  herc         Hercules command

  scp          Send scp command

  pscp         Send prio message scp command

  sf+dev       add shadow file
  sf-dev       delete shadow file
  sfc          compress shadow files
  sfk          check shadow files
  sfd          display shadow file stats

  t{+/-}dev    turn CCW tracing on/off
  s{+/-}dev    turn CCW stepping on/off
  t{+/-}CKD    turn CKD_KEY tracing on/off
  f{+/-}adr    mark frames unusable/usable

The ipl command may also be used to perform a load from cdrom or server. For example if a standard SuSE S/390 Linux distribution CD is loaded and mounted on /cdrom for example, this cdrom may then be ipl-ed by: ipl /cdrom/suse.ins

The attach and detach commands are used to dynamically add or remove devices from the configuration, and the define command can be used to alter the device number of an existing device.

The devinit command can be used to reopen an existing device. The args (if specified) override the arguments specified in the configuration file for this device. The device type cannot be changed and must not be specified. This command can be used to rewind a tape, to mount a new tape or disk image file on an existing device, to load a new card deck into a reader, or to close and reopen a printer or punch device.

In single-step mode, pressing the enter key will advance to the next instruction.

There is also an alternate semi-graphical control panel. Press Esc to switch between the command line format and the semi-graphical format. Press ? to obtain help in either control panel.

Some commands also offer additional help information regarding their syntax, etc. Enter  "help <command name>"   to display this additional help information. (Note: not every command supports help)

When a command is prefixed with '-', the the command will not be redisplayed at the console. This can be used in scripts and is also used internally when commands are to be invoked without being redisplayed at the panel.

The  hercules.rc  (run-commands)  file

Hercules also supports the ability to automatically execute panel commands upon startup via the 'run-commands' file. If the run-commands file is found to exist when Hercules starts, each line contained within it is read and interpreted as a panel command exactly as if the command were entered from the HMC system console.

The default filename for the run-commands file is "hercules.rc", but may be overridden by setting the "HERCULES_RC" environment variable to the desired filename.

Except for the 'pause' command (see paragraph further below), each command read from the run-commands file is logged to the console preceded by a '> ' (greater-than sign) character so you can easily distinguish between panel commands entered from the keyboard from those entered via the .rc file.

Lines starting with '#' are treated as "silent comments" and are thus not logged to the console. Line starting with '*' however are treated as "loud comments" and will be logged.

In addition to being able to execute any valid panel command (including the 'sh' shell command) via the run-commands file, an additional 'pause nnn' command is supported in order to introduce a brief delay before reading and processing the next line in the file. The value nnn can be any number from 1 to 999 and specifies the number of seconds to delay before reading the next line. Creative use of the run-commands file can completely automate Hercules startup.

The "Hercules Automatic Operator" (HAO) Facility

The Hercules Automatic Operator (HAO) feature is a facility which can automatically issue panel commands in response to specific messages appearing on the Hercules console.

To use the Hercules Automatic Operator facility, you first define a "rule" consisting of a "target" and an associated "command". The "target" is a regular expression pattern used to match against the text of the various messages that Hercules issues as it runs. Whenever a match is found, the rule "fires" and its associated command is automatically issued.

The Hercules Automatic Operator facility only operates on messages issued to the Hercules console. These messages may originate from Hercules itself, or from the guest operating system via the SCP SYSCONS interface or via the integrated console printer-keyboard (3215-C or 1052-C). HAO cannot intercept messages issued by the guest operating system to its own terminals.

Defining a Rule

To define a HAO rule, enter the command:

   hao tgt target

to define the rule's "target" match pattern followed by the command:

   hao cmd command

to define the rule's associated panel-command.

The target is a regular expression as defined by your host platform. When running on Linux, Hercules uses POSIX Extended Regular Expression syntax. On a Windows platform, regular expression support is provided by Perl Compatible Regular Expression (PCRE). The HAO facility can only be used if regular expression support was included in Hercules at build time.

The associated command is whatever valid Hercules panel command you wish to issue in response to a message being issued that matches the given target pattern.

Substituting substrings in the command

The command may contain special variables $1, $2, etc, which will be replaced by the values of "capturing groups" in the match pattern. A capturing group is a part of the regular expression enclosed in parentheses which is matched with text in the target message. In this way, commands may be constructed which contain substrings extracted from the message which triggered the command.

The following special variables are recognized:

Note that substitution of a $n variable does not occur if there are fewer than n capturing groups in the regular expression.

As an example, the rule below issues the command 'i 001F' in response to the message HHCTE014I 3270 device 001F client connection reset:

   hao tgt HHCTE014I 3270 device ([0-9A-F]{3,4})
   hao cmd i $1

Another example, shown below, illustrates how the dot matrix display of a 3480 tape unit might be used to implement an automatic tape library:

   hao tgt HHCTA010I ([0-9A-F]{4}): Now Displays: (?:".{8}" / )?"M([A-Z0-9]{1,6})\s*S"
   hao cmd devinit $1 /u/tapes/$2.awstape
Other commands and limitations

To delete a fully or partially defined HAO rule, first use the 'hao list' command to list all of the defined (or partially defined) rules, and then use the 'hao del nnn' command to delete the specific rule identified by nnn (all rules are assigned numbers as they are defined and are thus identified by their numeric value). Optionally, you can delete all defined or partially defined rules by issuing the command 'hao clear'.

The current implementation limits the total number of defined rules to 64. This limit may be raised by increasing the value of the HAO_MAXRULE constant in hao.c and rebuilding Hercules.

All defined rules are checked for a match each time Hercules issues a message. There is no way to specify "stop processing subsequent rules". If a message is issued that matches two or more rules, each associated command is then issued in sequence.

Technical Support

For technical support, please see the Hercules Technical Support page.


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