# Hercules Version 3: System Message Overview

This page describes the system messages for the Hercules S/370, ESA/390, and z/Architecture emulator.

### Message format

All Hercules-issued messages are of the form: `HHCmmnnns text` where:

`HHC`
  is the message prefix for Hercules. All Hercules messages will have this prefix.
`mm`
  specifies the function that issued the message, from the following list:
  `CA`
    Communication Adapter emulation
  `CF`
    Configuration file processing
  `CP`
    CPU emulation
  `CT`
    Channel-to-channel adapter emulation
  `CU`
    CCKD utility
  `DA`
    DASD emulation (both CKD and FBA)
  `DC`
    `dasdcopy`
  `DG`
    `dyngui.dll`
  `DI`
    `dasdinit`
  `DL`
    `dasdload`
  `DS`
    `dasdisup`
  `DT`
    `dasdcat`
  `DU`
    DASD utilities common functions
  `HD`
    Hercules Dynamic Loader
  `HE`
    `hetinit`
  `HG`
    `hetget`
  `HM`
    `hetmap`
  `HT`
    HTTP server
  `HU`
    `hetupd`
  `IF`
    `hercifc` (Network interface configuration handler)
  `IN`
    Hercules initialization
  `LC`
    LCS emulation
  `LG`
    System Log functions
  `PN`
    Hercules control panel command messages
  `PR`
    Printer emulation
  `PU`
    Card punch emulation
  `RD`
    Card reader emulation
  `SD`
    Socket devices common functions
  `TA`
    Tape device emulation
  `TC`
    `tapecopy`
  `TE`
    1052 and 3270 terminal emulation
  `TM`
    `tapemap`
  `TS`
    `tapesplt`
  `TT`
    TOD Clock and Timer Services
  `TU`
    TUN/TAP driver support
  `VM`
    VM/CP emulation facility
`nnn`
  Specific message number, assigned more or less sequentially.
`s`
  Message severity:
  `S`
    Severe error. Causes immediate termination of Hercules.
  `E`
    Error. The function being requested did not execute correctly, but Hercules should continue running.
  `W`
    Warning. Not necessarily an error, but something to take note of and possibly correct.
  `I`
    Information. General messages that do not require any further action.
  `A`
    Action. You need to do something.
`text`
  Message text.

You may look up any message by following the link from the function identifier in the above list.

If you have a question about Hercules, see the Hercules Frequently-Asked Questions page.

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