Bochs/bochs/doc/man/bochsrc.5

.\"Document Author:  Timothy R. Butler   -   tbutler@uninetsolutions.com"
.TH bochsrc 5 "13 Mar 2011" "bochsrc" "The Bochs Project"
.\"SKIP_SECTION"
.SH NAME
bochsrc \- Configuration file for Bochs.
.\"SKIP_SECTION"
.SH DESCRIPTION
.LP
Bochsrc   is  the   configuration   file  that specifies
where  Bochs should look for disk images,  how the Bochs
emulation layer  should  work,  etc.   The  syntax  used
for bochsrc  can also be used as command line  arguments
for Bochs. The .bochsrc  file should be placed either in
the current  directory  before running  Bochs or in your
home directory.

Starting with Bochs 1.3, you can use environment variables in
the bochsrc file, for example:

  floppya: 1_44="$IMAGES/bootdisk.img", status=inserted

Starting with version 2.0, two environment variables have a built-in
default value which is set at compile time.  $BXSHARE points to the
"share" directory which is typically /usr/local/share/bochs on UNIX
machines.  See the $(sharedir) variable in the Makefile for the exact
value.  $BXSHARE is used by disk images to locate the directory where
the BIOS images and keymaps can be found.  If $BXSHARE is not defined, Bochs
will supply the default value.  Also, $LTDL_LIBRARY_PATH points to a list of
directories (separated by colons if more than one) to search in for Bochs
plugins.  A compile-time default is provided if this variable is not defined
by the user.
.\".\"DONT_SPLIT"
.SH OPTIONS

.TP
.I "#include"
This option includes another configuration file. It is
possible to put installation defaults in a global config
file (e.g. location of rom images).

Example:
  #include /etc/bochsrc

.TP
.I "config_interface:"
The configuration interface is a series of menus or dialog boxes that
allows you to change all the settings that control Bochs's behavior.
Depending on the platform there are up to 3 choices of configuration
interface: a text mode version called "textconfig" and two graphical versions
called "win32config" and "wx".  The text mode version uses stdin/stdout and
is always compiled in, unless Bochs is compiled for wx only. The choice
"win32config" is only available on win32 and it is the default there.
The choice "wx" is only available when you use "--with-wx" on the configure
command.  If you do not write a config_interface line, Bochs will
choose a default for you.

.B NOTE:
if you use the "wx" configuration interface, you must also use
the "wx" display library.

Example:
  config_interface: textconfig

.TP
.I "display_library:"
The display library is the code that displays the Bochs VGA screen.  Bochs
has a selection of about 10 different display library implementations for
different platforms.  If you run configure with multiple --with-* options,
the display_library command lets you choose which one you want to run with.
If you do not write a display_library line, Bochs will choose a default for
you.

The choices are:
  x           X windows interface, cross platform
  win32       native win32 libraries
  carbon      Carbon library (for MacOS X)
  beos        native BeOS libraries
  macintosh   MacOS pre-10
  amigaos     native AmigaOS libraries
  sdl         SDL library, cross platform
  term        text only, uses curses/ncurses library, cross platform
  rfb         provides an interface to AT&T's VNC viewer, cross platform
  wx          wxWidgets library, cross platform
  nogui       no display at all

Some display libraries now support specific option to control their
behaviour. See the examples below for currently supported options.

.B NOTE:
if you use the "wx" configuration interface, you must also use
the "wx" display library.

Examples:
  display_library: x
  display_library: rfb, options="timeout=60"  # time to wait for client
  display_library: sdl, options="fullscreen"  # startup in fullscreen mode
  display_library: x, options="hideIPS" # disable IPS output in status bar
  display_library: x, options="gui_debug" # use GTK debugger gui


.TP
.I "romimage:"
The ROM BIOS controls what the PC does when it first powers on.  Normally, you
can use a precompiled BIOS in the source or binary distribution called
.B BIOS-bochs-latest.
The default ROM BIOS is usually loaded starting at address 0xe0000, and it is
exactly 128k long. The legacy version of the Bochs BIOS is usually loaded starting
at address 0xf0000, and it is exactly 64k long.
You can also use the environment variable $BXSHARE to specify the location of the BIOS.
The usage of external large BIOS images (up to 512k) at memory top is
now supported, but we still recommend to use the BIOS distributed with Bochs.
The start address is optional, since it can be calculated from image size.

Examples:
  romimage: file=bios/BIOS-bochs-latest
  romimage: file=$BXSHARE/BIOS-bochs-legacy
  romimage: file=mybios.bin, address=0xfff80000
  romimage: file=mybios.bin

.TP
.I "cpu:"
This defines cpu-related parameters inside Bochs:

count:

Set the number of processors:cores per processor:threads per core when
Bochs is compiled for SMP emulation. Bochs currently supports up to
8 processors. If Bochs is compiled without SMP support, it won't accept
values different from 1.

quantum:

Maximum amount of instructions allowed to execute by processor before
returning control to another cpu. This option exists only in Bochs
binary compiled with SMP support.

reset_on_triple_fault:

Reset the CPU when triple fault occur (highly recommended) rather than
PANIC. Remember that if you trying to continue after triple fault the
simulation will be completely bogus !

msrs:

Define path to user CPU Model Specific Registers (MSRs) specification.
See example in msrs.def.

ignore_bad_msrs:

Ignore MSR references that Bochs does not understand; print a warning
message instead of generating #GP exception. This option is enabled
by default but will not be avaiable if configurable MSRs are enabled.

ips:

Emulated Instructions Per Second.  This is the
number of IPS that Bochs is capable of running
on your machine.  You can recompile Bochs with
--enable-show-ips option enabled, to find your
workstation's capability.  Measured IPS value
will then be logged into your log file or status
bar (if supported by the gui).

IPS is used to calibrate  many  time-dependent
events   within   the  bochs  simulation.  For
example, changing IPS affects the frequency of
VGA updates, the duration of time before a key
starts to autorepeat,  and the measurement  of
BogoMips and other benchmarks.

Example Specifications[1]
 Bochs Machine/Compiler                                Mips
 -------------------------------------------------------------------
 2.3.7 3.2Ghz Intel Core 2 Q9770 with WinXP/g++ 3.4    50 to 55 Mips
 2.3.7 2.6Ghz Intel Core 2 Duo with WinXP/g++ 3.4      38 to 43 Mips
 2.2.6 2.6Ghz Intel Core 2 Duo with WinXP/g++ 3.4      21 to 25 Mips
 2.2.6 2.1Ghz Athlon XP with Linux 2.6/g++ 3.4         12 to 15 Mips
 2.0.1 1.6Ghz Intel P4 with Win2000/g++ 3.3             5 to  7 Mips

 [1]  IPS measurements depend on OS and compiler
configuration  in addition  to processor clock
speed.

Example:
  cpu: count=2, ips=10000000, msrs="msrs.def"

.TP
.I "cpuid:"
This defines features and functionality supported by Bochs emulated CPU:

mmx:

Select MMX instruction set support.
This option exists only if Bochs compiled with BX_CPU_LEVEL >= 5.

apic:

Select APIC configuration (LEGACY/XAPIC/X2APIC).
This option exists only if Bochs compiled with BX_CPU_LEVEL >= 5.

sep:

Select SYSENTER/SYSEXIT instruction set support.
This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6.

sse:

Select SSE instruction set support.
Any of NONE/SSE/SSE2/SSE3/SSSE3/SSE4_1/SSE4_2 could be selected.
This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6.

aes:

Select AES instruction set support.
This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6.

movbe:

Select MOVBE Intel(R) Atom instruction support.
This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6.

xsave:

Select XSAVE extensions support.
This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6.

xsaveopt:

Select XSAVEOPT instruction support.
This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6.

avx:

Select AVX instruction set support.
This option exists only if Bochs compiled with --enable-avx option.

avx_f16c:

Select AVX float16 convert instructions support.
This option exists only if Bochs compiled with --enable-avx option.

1g_pages:

Enable 1G page size support in long mode.
This option exists only if Bochs compiled with x86-64 support.

pcid:

Enable Process-Context Identifiers (PCID) support in long mode.
This option exists only if Bochs compiled with x86-64 support.

smep:

Enable Supervisor Mode Execution Protection (SMEP) support.
This option exists only if Bochs compiled with BX_CPU_LEVEL >= 6.

mwait:

Select MONITOR/MWAIT instructions support.
This option exists only if Bochs compiled with --enable-monitor-mwait.

mwait_is_nop:

When this option is enabled MWAIT will not put the CPU into a sleep state.
This option exists only if Bochs compiled with --enable-monitor-mwait.

family:

Set family information returned by CPUID. Default family value determined
by configure option --enable-cpu-level.

model:

Set model information returned by CPUID. Default model value is 3.

stepping:

Set stepping information returned by CPUID. Default stepping value is 3.

vendor_string:

Set the CPUID vendor string returned by CPUID(0x0).  This should be a
twelve-character ASCII string.

brand_string:

Set the CPUID vendor string returned by CPUID(0x80000002 .. 0x80000004).
This should be at most a forty-eight-character ASCII string.

cpuid_limit_winnt:

Determine whether to limit maximum CPUID function to 3. This mode is
required to workaround WinNT installation and boot issues.

Example:
  cpuid: mmx=1, sep=1, sse=sse4_2, xapic=1, aes=1, movbe=1, xsave=1, cpuid_limit_winnt=0

.TP
.I "megs:"
Set the number of Megabytes of physical memory you want to emulate.
The default is 32MB, most OS's won't need more than that.
The maximum amount of memory supported is 2048Mb.

Example:
  megs: 32

.TP
.I "optromimage1: \fP, \fIoptromimage2: \fP, \fIoptromimage3: \fPor \fIoptromimage4:"
You may now load up to 4 optional ROM images. Be sure to use a
read-only area, typically between C8000 and EFFFF. These optional
ROM images should not overwrite the rombios (located at
F0000-FFFFF) and the videobios (located at C0000-C7FFF).
Those ROM images will be initialized by the bios if they contain
the right signature (0x55AA).
It can also be a convenient way to upload some arbitrary code/data
in the simulation, that can be retrieved by the boot loader

Example:
  optromimage1: file=optionalrom.bin, address=0xd0000

.TP
.I "vgaromimage:"
You also need to load a VGA ROM BIOS into 0xC0000.

Examples:
  vgaromimage: file=bios/VGABIOS-elpin-2.40
  vgaromimage: file=bios/VGABIOS-lgpl-latest
  vgaromimage: file=$BXSHARE/VGABIOS-lgpl-latest

.TP
.I "vga:"
Here you can specify the display extension to be used. With the value 'none'
you can use standard VGA with no extension. Other supported values are 'vbe'
for Bochs VBE and 'cirrus' for Cirrus SVGA support.

Examples:
  vga: extension=cirrus
  vga: extension=vbe

.TP
.I "floppya: \fPor \fIfloppyb:"

Point  this to  the pathname of a floppy image
file or  device.  Floppya is the  first drive,
and  floppyb is the  second drive.  If  you're
booting from a floppy, floppya should point to
a bootable disk.

You can set the initial status of the media to
\&'ejected' or 'inserted'. Usually you will want
to use 'inserted'.

The parameter 'type' can be used to enable the floppy drive without media
and status specified. Usually the drive type is set up based on the media type.

The optional parameter 'write_protected' can be used to control the media
write protect switch. By default it is turned off.

Example:

2.88M 3.5" media:
  floppya: 2_88=path, status=ejected

1.44M 3.5" media (write protected):
  floppya: 1_44=path, status=inserted, write_protected=1

1.2M  5.25" media:
  floppyb: 1_2=path, status=ejected

720K  3.5" media:
  floppya: 720k=path, status=inserted

360K  5.25" media:
  floppya: 360k=path, status=inserted

Autodetect floppy media type:
  floppya: image=path, status=inserted

Use directory as 1.44M VFAT media:
  floppya: 1_44=vvfat:path, status=inserted

1.44M 3.5" floppy drive, no media:
  floppya: type=1_44

.TP
.I "ata0: \fP, \fIata1: \fP, \fIata2: \fPor \fIata3:"

These options enables up to 4 ata channels. For each channel
the two base io addresses and the irq must be specified.
ata0 and ata1 are enabled by default, with the values shown below.

Examples:
   ata0: enabled=1, ioaddr1=0x1f0, ioaddr2=0x3f0, irq=14
   ata1: enabled=1, ioaddr1=0x170, ioaddr2=0x370, irq=15
   ata2: enabled=1, ioaddr1=0x1e8, ioaddr2=0x3e0, irq=11
   ata3: enabled=1, ioaddr1=0x168, ioaddr2=0x360, irq=9

.TP
.I "ata\fR[\fB0-3\fR]\fI-master: \fPor \fIata\fR[\fB0-3\fR]\fI-slave:"

This defines the type and characteristics of all attached ata devices:
   type=       type of attached device [disk|cdrom]
   path=       path of the image
   mode=       image mode [flat|concat|external|dll|sparse|vmware3|undoable|growing|volatile], only valid for disks
   cylinders=  only valid for disks
   heads=      only valid for disks
   spt=        only valid for disks
   status=     only valid for cdroms [inserted|ejected]
   biosdetect= type of biosdetection [none|auto], only for disks on ata0 [cmos]
   translation=type of translation of the bios, only for disks [none|lba|large|rechs|auto]
   model=      string returned by identify device command
   journal=    optional filename of the redolog for undoable, volatile and vvfat disks

Point this at a hard disk image file, cdrom iso file,
or a physical cdrom device.
To create a hard disk image, try running bximage.
It will help you choose the size and then suggest a line that
works with it.

In UNIX it is possible to use a raw device as a Bochs hard disk,
but WE DON'T RECOMMEND IT.

The path is mandatory for hard disks. Disk geometry autodetection works with
images created by bximage if CHS is set to 0/0/0 (cylinders are calculated
using  heads=16 and spt=63). For other hard disk images and modes the
cylinders, heads, and spt are mandatory. In all cases the disk size reported
from the image must be exactly C*H*S*512.

The mode option defines how the disk image is handled. Disks can be defined as:
  - flat : one file flat layout
  - concat : multiple files layout
  - external : developer's specific, through a C++ class
  - dll : developer's specific, through a DLL
  - sparse : stackable, commitable, rollbackable
  - vmware3 : vmware3 disk support
  - undoable : flat file with commitable redolog
  - growing : growing file
  - volatile : flat file with volatile redolog
  - vvfat: local directory appears as read-only VFAT disk (with volatile redolog)

The disk translation scheme (implemented in legacy int13 bios functions, and used by
older operating systems like MS-DOS), can be defined as:
  - none : no translation, for disks up to 528MB (1032192 sectors)
  - large : a standard bitshift algorithm, for disks up to 4.2GB (8257536 sectors)
  - rechs : a revised bitshift algorithm, using a 15 heads fake physical geometry, for disks up to 7.9GB (15482880 sectors). (don't use this unless you understand what you're doing)
  - lba : a standard lba-assisted algorithm, for disks up to 8.4GB (16450560 sectors)
  - auto : autoselection of best translation scheme. (it should be changed if system does not boot)

Default values are:
   mode=flat, biosdetect=auto, translation=auto, model="Generic 1234"

The biosdetect option has currently no effect on the bios

Examples:
   ata0-master: type=disk, path=10M.sample, cylinders=306, heads=4, spt=17
   ata0-slave:  type=disk, path=20M.sample, cylinders=615, heads=4, spt=17
   ata1-master: type=disk, path=30M.sample, cylinders=615, heads=6, spt=17
   ata1-slave:  type=disk, path=46M.sample, cylinders=940, heads=6, spt=17
   ata2-master: type=disk, path=62M.sample, cylinders=940, heads=8, spt=17
   ata2-slave:  type=disk, path=112M.sample, cylinders=900, heads=15, spt=17
   ata3-master: type=disk, path=483M.sample, cylinders=1024, heads=15, spt=63
   ata3-slave:  type=cdrom, path=iso.sample, status=inserted

.TP
.I "com1: \fP, \fIcom2: \fP, \fIcom3: \fPor \fIcom4:"
This defines a serial port (UART type 16550A). In the 'term' you can specify
a device to use as com1. This can be a real serial line, or a pty.  To use
a pty (under X/Unix), create two windows (xterms, usually).  One of them will
run bochs, and the other will act as com1. Find out the tty the com1 window
using the `tty' command, and use that as the `dev' parameter.  Then do
`sleep 1000000' in the com1 window to keep the shell from messing with things,
and run bochs in the other window.  Serial I/O to com1 (port 0x3f8) will all
go to the other window.

Other serial modes are 'null' (no input/output), 'file' (output to a file
specified as the 'dev' parameter), 'raw' (use the real serial port - under
construction for win32) and 'mouse' (standard serial mouse - requires
mouse option setting 'type=serial' or 'type=serial_wheel')

Examples:
  com1: enabled=1, mode=term, dev=/dev/ttyp7
  com2: enabled=1, mode=file, dev=serial.out
  com1: enabled=1, mode=mouse

.TP
.I "parport1: \fPor \fIparport2:"
This defines a parallel (printer) port. When turned on and an output file is
defined the emulated printer port sends characters printed by the guest
OS into the output file. On some platforms a device filename can be used to
send the data to the real parallel port (e.g. "/dev/lp0" on Linux).

Examples:
  parport1: enabled=1, file=parport.out
  parport2: enabled=1, file="/dev/lp0"
  parport1: enabled=0

.TP
.I "boot:"
This defines the boot sequence. Now you can specify up to 3 boot drives,
which can be 'floppy', 'disk', 'cdrom' or 'network' (boot ROM).
Legacy 'a' and 'c' are also supported.

Example:
  boot: cdrom, floppy, disk

.TP
.I "floppy_bootsig_check:"
This disables the 0xaa55 signature check on boot floppies
The check is enabled by default.

Example:
  floppy_bootsig_check: disabled=1

.TP
.I "log:"
Give the path of the log file you'd like Bochs
debug and misc. verbiage to be written to.   If
you really don't want it, make it /dev/null.

Example:
  log: bochs.out
  log: /dev/tty               (unix only)
  log: /dev/null              (unix only)

.TP
.I "logprefix:"
This handles the format of the string prepended to each log line :
You may use those special tokens :
  %t : 11 decimal digits timer tick
  %i : 8 hexadecimal digits of cpu0 current eip
  %e : 1 character event type ('i'nfo, 'd'ebug, 'p'anic, 'e'rror)
  %d : 5 characters string of the device, between brackets

Default : %t%e%d

Examples:
  logprefix: %t-%e-@%i-%d
  logprefix: %i%e%d

.TP
.I "panic:"
If Bochs reaches  a condition  where it cannot
emulate correctly, it does a panic.  This  can
be a configuration problem  (like a misspelled
bochsrc line) or an emulation problem (like an
unsupported video mode). The  "panic"  setting
in  bochsrc  tells  Bochs  how to respond to a
panic.  You  can  set this to fatal (terminate
the session),  report   (print information  to
the console), or ignore (do nothing).

The safest setting is action=fatal. If you are
getting  panics,  you  can  try  action=report
instead.  If you allow Bochs to continue after
a panic, don't be surprised if you get strange
behavior or crashes if a panic occurs.  Please
report  panic  messages  unless  it is just  a
configuration  problem  like  "could  not find
hard drive image."

Example:
  panic: action=fatal


.TP
.I "error:"
Bochs produces an error message when it  finds
a condition that really shouldn't happen,  but
doesn't endanger the simulation. An example of
an error  might be  if the  emulated  software
produces an illegal disk command.

The "error" setting tells Bochs how to respond
to an error condition.   You can set  this  to
fatal  (terminate the session),  report (print
information to the  console),  or  ignore  (do
nothing).

Example:
  error: action=report

.TP
.I "info:"
This setting tells Bochs what to  do  when  an
event  occurs   that  generates  informational
messages.  You can  set this  to  fatal  (that
would not be very smart though), report (print
information to the  console),  or  ignore  (do
nothing).   For  general  usage,  the "report"
option is probably a good choice.

Example:
  info: action=report

.TP
.I "debug:"
This  setting  tells  Bochs what  to  do  with
messages intended to assist in debugging.  You
can set  this  to  fatal  (but you shouldn't),
report (print information to the  console), or
ignore (do nothing). You should generally  set
this  to  ignore,  unless  you are  trying  to
diagnose a particular problem.

.B NOTE:
When  action=report,   Bochs   may  spit  out
thousands of debug messages per second, which
can impact performance and fill up your disk.

Example:
  debug: action=ignore

.TP
.I "debugger_log:"
Give the path of the log file you'd like Bochs to log debugger output.
If you really don't want it, make it '/dev/null', or '-'.

Example:
  log: debugger.out
  log: /dev/null              (unix only)
  log: -

.TP
.I "sb16:"
This  defines the SB16 sound emulation. It can
have several of the  following properties. All
properties are in this format:
  sb16: property=value


.B PROPERTIES FOR sb16:

midi:

The  filename is where the midi data is  sent.
This can  be  a device  or just a file if  you
want to record the midi data.

midimode:

 0 = No data should be output.
 1 = output to device (system dependent - midi
 denotes the device driver).
 2 = SMF file output, including headers.
 3 = Output  the midi  data stream to the file
 (no  midi headers  and  no delta  times, just
 command and data bytes).

wave:

This  is the device/file where wave  output is
stored.

wavemode:

 0 = no data
 1 = output to device (system dependent - wave
 denotes the device driver).
 2 = VOC file output, including headers.
 3 = Output the raw wave stream to the file.

log:

The file to write the sb16 emulator messages to.

loglevel:

 0 = No log.
 1 = Resource changes, midi program and bank changes.
 2 = Severe errors.
 3 = All errors.
 4 = All errors plus all port accesses.
 5 = All  errors and port  accesses plus a lot
 of extra information.

It is possible to change the loglevel at runtime.

dmatimer:

Microseconds per second for a DMA cycle.  Make it smaller
to fix non-continuous sound.  750000 is  usually  a  good
value.  This  needs  a reasonably  correct   setting  for
the  IPS  parameter of the CPU option.  It is possible to
adjust the dmatimer at runtime.

Example for output to OSS:
  sb16: midimode=1, midi=/dev/midi00,
  wavemode=1, wave=/dev/dsp, loglevel=2,
  log=sb16.log, dmatimer=600000

Example for output to ALSA:
  sb16: midimode=1, midi=alsa:128:0,
  wavemode=1, wave=alsa,
  log=sb16.log, dmatimer=600000

.B NOTE:
The  examples are wrapped onto three  lines for
formatting  reasons, but  it should all be  on
one line in the actual bochsrc file.

.TP
.I "es1370:"
This defines the ES1370 sound emulation. The parameter 'enabled' controls the
presence of the device. In addition to this, it must be assigned to a PCI
slot. The 'wavedev' parameter is similar to the 'wave' parameter of the SB16
soundcard. Currently only the output of the DAC2 is sent to the wave device.

Examples:
  es1370: enabled=1, wavedev=""       # win32
  es1370: enabled=1, wavedev=alsa     # Linux with ALSA

.TP
.I "vga_update_interval:"
Video memory is scanned for updates and screen updated
every so many virtual seconds. The default value is
50000, about 20Hz. Keep in mind that you must tweak
the 'cpu: ips=N' directive to be as close to the number of
emulated instructions-per-second your  workstation can
do, for this to be accurate.

Example:
  vga_update_interval: 250000


.TP
.I "keyboard_serial_delay:"
Approximate time in microseconds that it takes
one  character  to   be  transfered  from  the
keyboard to controller over the serial path.

Example:
  keyboard_serial_delay: 200

.TP
.I "keyboard_paste_delay:"
Approximate time in microseconds between attempts to paste
characters to the keyboard controller. This leaves time for the
guest os to deal with the flow of characters.  The ideal setting
depends on how your operating system processes characters.  The
default of 100000 usec (.1 seconds) was chosen because it works
consistently in Windows.

If your OS is losing characters during a paste, increase the paste
delay until it stops losing characters.

Example:
  keyboard_paste_delay: 100000

.TP
.I "clock:"
This defines the parameters of the clock inside Bochs.

sync

This defines the method how to synchronize the Bochs internal time
with realtime. With the value 'none' the Bochs time relies on the IPS
value and no host time synchronization is used. The 'slowdown' method
sacrifices performance to preserve reproducibility while allowing host
time correlation. The 'realtime' method sacrifices reproducibility to
preserve performance and host-time correlation.
It is possible to enable both synchronization methods.

time0

Specifies the start (boot) time of the virtual machine. Use a time
value as returned by the time(2) system call. If no time0 value is
set or if time0 equal to 1 (special case) or if time0 equal 'local',
the simulation will be started at the current local host time.
If time0 equal to 2 (special case) or if time0 equal 'utc',
the simulation will be started at the current utc time.

Syntax:
  clock: sync=[none|slowdown|realtime|both], time0=[timeValue|local|utc]

Default value are sync=none, time0=local

Example:
  clock: sync=realtime, time0=938581955   # Wed Sep 29 07:12:35 1999

.TP
.I "mouse:"
This defines parameters for the emulated mouse type, the initial status
of the mouse capture and the runtime method to toggle it.

type

With the mouse type option you can select the type of mouse to emulate.
The default value is 'ps2'. The other choices are 'imps2' (wheel mouse
on PS/2), 'serial', 'serial_wheel' and 'serial_msys' (one com port requires
setting 'mode=mouse'). To connect a mouse to an USB port, see the 'usb_uhci'
or 'usb_ohci' option (requires PCI and USB support).

enabled

The Bochs gui creates mouse "events" unless the 'enabled' option is
set to 0. The hardware emulation itself is not disabled by this.
Unless you have a particular reason for enabling the mouse by default,
it is recommended that you leave it off. You can also toggle the mouse
usage at runtime (RFB, SDL, Win32, wxWidgets and X11 - see below).

toggle

The default method to toggle the mouse capture at runtime is to press the
CTRL key and the middle mouse button ('ctrl+mbutton'). This option allows
to change the method to 'ctrl+f10' (like DOSBox), 'ctrl+alt' (like QEMU)
or 'f12' (replaces win32 'legacyF12' option).

Examples:
  mouse: enabled=1
  mouse: type=imps2, enabled=1
  mouse: type=serial, enabled=1
  mouse: enabled=0, toggle=ctrl+f10

.TP
.I "private_colormap:"
Requests that the GUI create and use it's  own
non-shared colormap.  This  colormap  will  be
used when in the bochs window. If not enabled,
a shared  colormap  scheme  may be used.  Once
again, enabled=1  turns on this feature  and 0
turns it off.

Example:
  private_colormap: enabled=1

.TP
.I "i440fxsupport:"
This option controls the presence of the i440FX PCI chipset. You can
also specify the devices connected to PCI slots. Up to 5 slots are
available now. These devices are currently supported: cirrus, es1370, ne2k,
pcivga, pcidev, pcipnic and usb_ohci.

Example:
  i440fxsupport: enabled=1, slot1=pcivga, slot2=ne2k

.TP
.I "pcidev:"
Enables the mapping of a host PCI hardware device within the PCI subsystem of
the Bochs x86 emulator. This feature requires Linux as a host OS.

Example:
  pcidev: vendor=0x1234, device=0x5678

The vendor and device arguments should contain the vendor ID respectively the
device ID of the PCI device you want to map within Bochs.
.B The PCI mapping is still very experimental.

.TP
.I "ne2k:"
Defines the characteristics of an attached ne2000 isa card :
   ioaddr=IOADDR,
   irq=IRQ,
   mac=MACADDR,
   ethmod=MODULE,
   ethdev=DEVICE,
   script=SCRIPT

.B PROPERTIES FOR ne2k:

ioaddr, irq:
You probably won't need to change ioaddr and irq, unless there are IRQ conflicts.
These parameters are ignored if the NE2000 is assigned to a PCI slot.

mac:
The MAC address MUST NOT match the address of any machine on the net.
Also, the first byte must be an even number (bit 0 set means a multicast
address), and you cannot use ff:ff:ff:ff:ff:ff because that's the broadcast
address.  For the ethertap module, you must use fe:fd:00:00:00:01.  There may
be other restrictions too.  To be safe, just use the b0:c4... address.

ethmod:
The ethmod value defines which low level OS specific module to be used
to access physical ethernet interface. Current implemented values include
 - fbsd   : ethernet on freebsd and openbsd
 - linux  : ethernet on linux
 - win32  : ethernet on win32
 - tap    : ethernet through a linux tap interface
 - tuntap : ethernet through a linux tuntap interface
 - slirp  : ethernet backend for Slirp and a builtin DHCP server

If you don't want to make connections to any physical networks,
you can use the following 'ethmod's to simulate a virtual network.
 - null   : All packets are discarded, but logged to a few files
 - arpback: ARP is simulated (disabled by default)
 - vde    : Virtual Distributed Ethernet
 - vnet   : ARP, ICMP-echo(ping), DHCP and TFTP are simulated
            The virtual host uses 192.168.10.1
            DHCP assigns 192.168.10.2 to the guest
            The TFTP server use ethdev for the root directory and doesn't
            overwrite files

ethdev:
The ethdev value is the name of the network interface on your host
platform.  On UNIX machines, you can get the name by running ifconfig.  On
Windows machines, you must run niclist to get the name of the ethdev.
Niclist source code is in misc/niclist.c and it is included in Windows
binary releases.

script:
The script value is optional, and is the name of a script that
is executed after bochs initialize the network interface. You can use
this script to configure this network interface, or enable masquerading.
This is mainly useful for the tun/tap devices that only exist during
Bochs execution. The network interface name is supplied to the script
as first parameter

Examples:
  ne2k: ioaddr=0x300, irq=9, mac=b0:c4:20:00:00:00, ethmod=fbsd, ethdev=xlo
  ne2k: ioaddr=0x300, irq=9, mac=b0:c4:20:00:00:00, ethmod=linux, ethdev=eth0
  ne2k: ioaddr=0x300, irq=9, mac=b0:c4:20:00:00:01, ethmod=win32, ethdev=MYCARD
  ne2k: ioaddr=0x300, irq=9, mac=fe:fd:00:00:00:01, ethmod=tap, ethdev=tap0
  ne2k: ioaddr=0x300, irq=9, mac=fe:fd:00:00:00:01, ethmod=tuntap, ethdev=/dev/net/tun0, script=./tunconfig
  ne2k: ioaddr=0x300, irq=9, mac=b0:c4:20:00:00:01, ethmod=vde, ethdev="/tmp/vde.ctl"
  ne2k: ioaddr=0x300, irq=9, mac=b0:c4:20:00:00:01, ethmod=vnet, ethdev="c:/temp"

.TP
.I "pnic:"
To support the Bochs/Etherboot pseudo-NIC, Bochs must be compiled with the
--enable-pnic configure option. It accepts the same syntax (for mac, ethmod,
ethdev, script) and supports the same networking modules as the NE2000 adapter.
In addition to this, it must be assigned to a PCI slot.

Example:
  pnic: enabled=1, mac=b0:c4:20:00:00:00, ethmod=vnet

.TP
.I "keyboard_mapping:"
This enables a remap of a physical localized keyboard to a
virtualized us keyboard, as the PC architecture expects.
If enabled, the keymap file must be specified.

 Examples:
   keyboard_mapping: enabled=1, map=gui/keymaps/x11-pc-de.map

.TP
.I "keyboard_type:"
Type of emulated keyboard sent back  to the OS
to a "keyboard identify"  command.  It must be
one of "xt", "at" or "mf".

Example:
  keyboard_type: mf

.TP
.I "user_shortcut:"
This defines the keyboard shortcut to be sent when you press the "user"
button in the header bar. The shortcut string is a combination of maximum
3 key names (listed below) separated with a '-' character.

Valid key names:

"alt", "bksl", "bksp", "ctrl", "del", "down", "end", "enter", "esc",
"f1", ... "f12", "home", "ins", "left", "menu", "minus", "pgdwn", "pgup", "plus",
"right", "shift", "space", "tab", "up", "win", "print" and "power".

Example:
  user_shortcut: keys=ctrl-alt-del

.TP
.I "cmosimage:"
This defines image file that can be loaded into the CMOS RAM at startup.
The rtc_init parameter controls whether initialize the RTC with values stored
in the image. By default the time0 argument given to the clock option is used.
With 'rtc_init=image' the image is the source for the initial time.

Example:
  cmosimage: file=cmos.img, rtc_init=time0

.TP
.I "usb_uhci:"
This option controls the presence of the USB root hub which is a part
of the i440FX PCI chipset. With the portX option you can connect devices
to the hub (currently supported: 'mouse', 'tablet', 'keypad', 'disk', 'cdrom',
'hub' and 'printer').

The optionsX parameter can be used to assign specific options to the device
connected to the corresponding USB port. Currently this feature is only used
to set the speed reported by device and by the 'disk' device to specify
an alternative redolog file of some image modes.

If you connect the mouse or tablet to one of the ports, Bochs forwards the
mouse movement data to the USB device instead of the selected mouse type.
When connecting the keypad to one of the ports, Bochs forwards the input of
the numeric keypad to the USB device instead of the PS/2 keyboard.

To connect a 'flat' mode image as an USB hardisk you can use the 'disk' device
with the path to the image separated with a colon. To use other disk image modes
similar to ATA disks the syntax 'disk:mode:filename' must be used (see below).

To emulate an USB cdrom you can use the 'cdrom' device name and the path to
an ISO image or raw device name also separated with a colon. An option to
insert/eject media is available in the runtime configuration.

The device 'printer' emulates the HP Deskjet 920C printer. The PCL data is
sent to a file specified in bochsrc.txt. The current code appends the PCL
code to the file if the file already existed. It would probably be nice to
overwrite the file instead, asking user first.

Example:
  usb_uhci: enabled=1, port1=mouse, port2=disk:usbstick.img
  usb_uhci: enabled=1, port1=hub:7, port2=disk:growing:usbdisk.img
  usb_uhci: enabled=1, port1=printer:printdata.bin, port2=cdrom:image.iso

.TP
.I "usb_ohci:"
This option controls the presence of the USB OHCI host controller with a
2-port hub. The portX option accepts the same device types with the same
syntax as the UHCI controller (see above). The OHCI HC must be assigned to
a PCI slot.

Example:
  usb_ohci: enabled=1

.TP
.I "plugin_ctrl:"
Controls the presence of optional plugins without a separate option.
By default all existing plugins are enabled. These plugins are currently
supported: 'acpi', 'biosdev', 'extfpuirq', 'gameport', 'iodebug', 'pci_ide', 'speaker' and 'unmapped'.

Example:
  plugin_ctrl: biosdev=0, speaker=0

.TP
.I "user_plugin:"
Load user-defined plugin. This option is available only if Bochs is
compiled with plugin support. Maximum 8 different plugins are supported.
See the example in the Bochs sources how to write a plugin device.

Example:
  user_plugin: name=testdev

.\"SKIP_SECTION"
.SH LICENSE
This program  is distributed  under the terms of the  GNU
Lesser General Public License as published  by  the  Free
Software  Foundation.  See  the  COPYING file located  in
/usr/share/doc/bochs/ for details on the license and
the lack of warranty.
.\"SKIP_SECTION"
.SH AVAILABILITY
The latest version of this program can be found at:
  http://bochs.sourceforge.net/getcurrent.html
.\"SKIP_SECTION"
.SH SEE ALSO
bochs(1), bochs-dlx(1), bximage(1), bxcommit(1)
.PP
.nf
The Bochs IA-32 Emulator site on the World Wide Web:
        http://bochs.sourceforge.net

Online Bochs Documentation
	http://bochs.sourceforge.net/doc/docbook
.fi
.\"SKIP_SECTION"
.SH AUTHORS
The   Bochs  emulator  was   created   by  Kevin   Lawton
(kevin@mandrakesoft.com),  and  is  currently  maintained
by the  members of  the  Bochs x86 Emulator Project.  You
can see a current roster of members at:
  http://bochs.sourceforge.net/getinvolved.html
.\"SKIP_SECTION"
.SH BUGS
Please  report all  bugs to the bug tracker  on  our  web
site. Just go to http://bochs.sourceforge.net, and click
"Bug Reports" on the sidebar under "Feedback".
.PP
Provide a detailed description of the bug, the version of
the program you are running, the operating system you are
running the program on  and  the  operating   system  you
are running in the emulator.