When booting Plan 9 on a PC, the bootstrap programs described
in 9load(8) first read, via TFTP or a FAT filesystem on the boot
disk, a file containing configuration information. This file,
/cfg/pxe/hex–digits (TFTP; see 9load(8)) or plan9.ini (FAT), looks
like a shell script containing lines of the form
each of which defines a kernel or device parameter. Each name
assigned may be used as a variable in later definitions. The special
variables $bootdev and $bootpath are assigned a value based on
the device on which plan9.ini was found. For example, to boot
from kfs(4) on whichever device plan9.ini was found
Blank lines and Carriage Returns (\r) are ignored. # comments
are ignored, but are only recognised if # appears at the start
of a line.
For devices, the generic format of value is
specifying the controller type, the base I/O port of the interface,
its interrupt level, the physical starting address of any mapped
memory, the length in bytes of that memory, the DMA channel, and
for Ethernets an override of the physical network address. Not
all elements are relevant to all devices; the relevant values
and their defaults are defined below in the description of each
The file is used by the bootstrap programs and the kernel to configure
the hardware available, although nowadays the kernel can usually
detect the attached hardware by itself. The information it contains
is also passed to the boot process, and subsequently other programs,
as environment variables (see boot(8)).
However, values whose names begin with an asterisk * are used
by the kernel and are stored in #ec rather than #e.
The following sections describe how variables are used.
type=TYPE [port=N] [irq=N] [mem=N] [size=N] [dma=N] [ea=N]|
Many cards are software configurable and do not require all options.
Unspecified options default to the factory defaults.
Known TYPEs are
This defines an Ethernet interface. X, a unique monotonically
increasing number beginning at 0, identifies an Ethernet card
to be probed at system boot. Probing stops when a card is found
or there is no line for etherX+1. After probing as directed by
the etherX lines, any remaining Ethernet cards that can be
automatically detected are added. Almost all cards can be automatically
detected. For debugging purposes, automatic probing can be disabled
by specifying the line *noetherprobe=.
igbe The Intel 8254X Gigabit Ethernet controllers, as found on
the Intel PRO/1000 adapters for copper (not fiber). Completely
rtl8169The Realtek 8169 Gigabit Ethernet controller. Completely
The Intel 8256, 8257[1–9], and 82580 Gigabit Ethernet PCI–Express
controllers. Completely configurable.|
ga620 Netgear GA620 and GA620T Gigabit Ethernet cards, and other
cards using the Alteon Acenic chip such as the Alteon Acenic fiber
and copper cards, the DEC DEGPA–SA and the SGI Acenic. Completely
configurable. Can't boot through these due to enormous firmware
dp83820National Semiconductor DP83820–based Gigabit Ethernet adapters,
notably the D–Link DGE–500T. Completely configurable.
vgbe The VIA Velocity Gigabit Ethernet controller. Known to drive
the VIA8237 (ABIT AV8), but at 100Mb/s full–duplex only.
m10g The Myricom 10–Gigabit Ethernet 10G–PCIE–8A controller. Completely
i82598 The Intel 8259 10–Gigabit Ethernet PCI–Express controllers.
i82557 Cards using the Intel 8255 Fast Ethernet PCI Bus LAN
Controller such as the Intel EtherExpress PRO/100B. Completely
configurable, no options need be given. If you need to force the
media, specify one of the options (no value) 10BASE–T, 10BASE–2,
10BASE–5, 100BASE–TX, 10BASE–TFD,
2114x Cards using the Digital Equipment (now Intel) 2114x PCI Fast
Ethernet Adapter Controller, for example the Netgear FA310. Completely
configurable, no options need be given. Media can be specified
the same was as for the i82557. Some cards using the PNIC and
PNIC2 near–clone chips may also work.
83815 National Semiconductor DP83815–based adapters, notably the
Netgear FA311, Netgear FA312, and various SiS built–in controllers
such as the SiS900. On the SiS controllers, the Ethernet address
is not detected properly; specify it with an ea= attribute. Completely
rtl8139The Realtek 8139 Fast Ethernet controller. Completely configurable.
100BASE–TXFD, 100BASE–T4, 100BASE–FX, or 100BASE–FXFD. Completely
vt6102 The VIA VT6102 Fast Ethernet Controller (Rhine II).
vt6105mThe VIA VT6105M Fast Ethernet Controller (Rhine III).
elnk3 The 3COM Etherlink III series of cards including the 5x9,
59x, and 905 and 905B. Completely configurable, no options need
be given. The media may be specified by setting media= to the
value 10BaseT, 10Base2, 100BaseTX, 100BaseFX, aui, and mii. If
you need to force full duplex, because
SMC 91cXX chip–based PCMCIA adapters, notably the SMC EtherEZ card.|
3c589 The 3COM 3C589 series PCMCIA cards, including the 3C562 and
the 589E. There is no support for the modem on the 3C562. Completely
configurable, no options need be given. Defaults are
for example the Ethernet switch does not negotiate correctly,
just name the word (no value) fullduplex or 100BASE–TXFD. Similarly,
to force 100Mbit operation, specify force100. Port 0x110 is used
for the little ISA configuration dance.|
ec2t The Linksys Combo PCMCIA EthernetCard (EC2T), EtherFast 10/100
PCMCIA cards (PCMPC100) and integrated controllers (PCM100), the
Netgear FA410TX 10/100 PCMCIA card and the Accton EtherPair–PCMCIA
(EN2216). Completely configurable, no options need be given. Defaults
The media may be specified as media=10BaseT or media=10Base2.
ne2000 Not software configurable iff ISA; PCI clones or supersets
are software configurable; includes the Realtek 8029 clone used
by Parallels. 16–bit card. Defaults are
These cards are NE2000 clones. Other NE2000 compatible PCMCIA
cards may be tried with the option
where string is a unique identifier string contained in the attribute
memory of the card (see pcmcia(8)); unlike most options in plan9.ini,
this string is case–sensitive. The option dummyrr= can be used
to turn off (0) or on (1) a dummy remote read in the driver in
such cases, depending on how
NE2000 compatible they are.
port=0x300 irq=2 mem=0x04000 size=0x4000|
The option (no value) nodummyrr is needed on some (near) clones
to turn off a dummy remote read in the driver.
wd8003 Includes WD8013 and SMC Elite and Elite Ultra cards. There
are varying degrees of software configurability. Cards may be
in either 8–bit or 16–bit slots. Defaults are
The AMD PCnet PCI Ethernet Adapter (AM79C970). (This is the Ethernet
adapter used by VMware.) Completely configurable, no options need
sink A /dev/null for Ethernet packets -- the interface discards sent
packets and never receives any. This is used to provide a test
bed for some experimental Ethernet bridging software.
port=0x280 irq=3 mem=0xD0000 size=0x2000|
BUG: On many machines only the 16 bit card works.
wavelanLucent Wavelan (Orinoco) IEEE 802.11b and compatible PCMCIA
cards. Compatible cards include the Dell TrueMobile 1150 and the
Linksys Instant Wireless Network PC Card. Port and IRQ defaults
are 0x180 and 3 respectively.
These cards take a number of unique options to aid in identifying
the card correctly on the 802.11b network. The network may be
ad hoc or managed (i.e. use an access point):|
and defaults to managed. The 802.11b network to attach to (managed
mode) or identify as (ad hoc mode), is specified by
and defaults to a null string. The card station name is given
and defaults to Plan 9 STA. The channel to use is given by
where number lies in the range 1 to 16 inclusive; the channel
is normally negotiated automatically.
If the card is capable of encryption, the following options may
and defaults to on.
sets the encryption key N (where N is in the range 1 to 4 inclusive)
to string; this will also set the transmit key to N (see below).
There are two formats for string which depend on the length of
the string. If it is exactly 5 or 13 characters long it is assumed
to be an alphanumeric key; if it is exactly 10 or 26
characters long the key is assumed to be in hex format (without
a leading 0x). The lengths are checked, as is the format of a
sets the transmit key to use to be number in the range 1 to 4
inclusive. If it is desired to exclude or include unencrypted
configures reception and defaults to inclusion.
The defaults are intended to match the common case of a managed
network with encryption and a typical entry would only require,
essid=left–armpit key1=afish key2=calledraawaru
if the port and IRQ defaults are used. These options may be set
after boot by writing to the device's ctl file using a space as
the separator between option and value, e.g.
echo 'key2 1d8f65c9a52d83c8e4b43f94af' >/net/ether0/0/ctl
Card–specific power management may be enabled/disabled by
yuk Some Marvell Yukon II 88e8057 chipsets. Completely configurable.
But not bootable due to missing 9load driver.
PCI Ethernet adapters that use the same Wavelan programming interface.
Currently the only tested cards are those based on the Intersil
Prism 2.5 chipset.|
(S)ATA and SAS controllers are autodetected.
This specifies the settings for a USB UHCI, OHCI or EHCI controller.
Like the Ethernet controllers, USB controllers are autodetected
after scanning for the ones listed in plan9.ini. Thus, most systems
will not need a usbX line. Also like the Ethernet controllers,
USB autoprobing can be disabled by specifying the line
Known TYPEs are
This defines a SCSI interface which cannot be automatically detected
by the kernel.
NCR/Symbios/LSI–Logic 53c8xx–based adapters and Mylex MultiMaster
(Buslogic BT–*) adapters are automatically detected and need no
By default, the NCR 53c8xx driver searches for up to 32 controllers.
This can be changed by setting the variable *maxsd53c8xx.
By default the Mylex driver resets SCSI cards by using both the
hard reset and SCSI bus reset flags in the driver interface. If
a variable *noscsireset is defined, the SCSI bus reset flag is
Adaptec 154x series of controllers (and clones). Almost completely
configurable, only the|
option need be given.
This specifies a space–separated list of Ethernet interfaces to
be bound at boot to the ATA–over–Ethernet driver, aoe(3). For example,
aoeif=ether0 ether1. Only interfaces on this list will initially
be accessible via AoE.
This specifies an ATA–over–Ethernet device accessible via the interfaces
named in aoeif on AoE shelf and slot to use as a root device for
Known types are
This defines a pre–USB sound interface.
sb16 Sound Blaster 16.
ess1688 A Sound Blaster clone.
The DMA channel may be any of 5, 6, or 7. The defaults are
This is typically done in order to reuse the IRQ for another device.
Plan 9 used to support various serial concentrators, including
the TTC 8 serial line card and various models in the Star Gate
Avanstar series of intelligent serial boards. These are no longer
supported; the much simpler Perle PCI–Fast4, PCI–Fast8, and PCI–Fast16
controllers have taken their places. These latter cards are
automatically detected and need no configuration lines.
The line serial=type=com can be used to specify settings for a
Plan 9 automatically configures COM1 and COM2, if found, as eia0
(port 0x3F8, IRQ4) and eia1 (port 0x2F8, IRQ3) respectively. These
devices can be disabled by adding a line:
This specifies where the mouse is attached. Value can be
ps2 the PS2 mouse/keyboard port. The BIOS setup procedure should
be used to configure the machine appropriately.
0 for COM1
an Intellimouse on the PS2 port.|
1 for COM2
Picks the UART line to call out on. This is used when connecting
to a file server over an async line. Value is the number of the
would use COM1 at 19,200 baud with odd parity.
This is used to specify the console device. The default value
is cga; a number 0 or 1 specifies COM1 or COM2 respectively. A
serial console is initially configured with the uart(3) configuration
string b9600 l8 pn s1, specifying 9600 baud, 8 bit bytes, no parity,
and one stop bit. If params is given, it will be used to
further configure the uart. Notice that there is no = sign in
the params syntax. For example,
Disable probing for and automatic configuration of PC card controllers.
If the default IRQ for the PCMCIA is correct, this entry can be
omitted. The value of type is ignored.
Disable probing for and automatic configuration of PCMCIA controllers.
This is used to specify an nvram device and optionally the length
of the ram and read/write offset to use. These values are consulted
by readnvram (see authsrv(2)). The most common use of the nvram
is to hold a secstore(1) password for use by factotum(4).
This is used by the WORM file server kernel to locate a file holding
information to configure the file system. The file cannot live
on a SCSI disk. The default is fd!0!plan9.nvr (sic), unless bootfile
is set, in which case it is plan9.nvr on the same disk as bootfile.
The syntax is either fd!unit!name or
hd!unit!name where unit is the numeric unit id. This variant syntax
is a vestige of the file server kernel's origins.
This is used to direct the actions of the bootstrap programs by
naming the device and file from which to load the kernel.
These are used by the bootstrap programs to identify the directory
dir to make the root directory for the kernel, and the file system
specifier spec (see mount in bind(2)) on which it can be found.
These are usually used to test variant file systems for distributions,
The value of this variable is passed to boot(8) by the kernel
as the name of the root file system. It is typically used to specify
additional arguments to pass to kfs(4) or ipconfig(8). For example,
if the system is to run from a local kfs(4) partition, the definition
might read bootargs=local!#S/sdC0/fs. See boot(8)
Suppress the root from prompt and use root as the answer instead.
Suppress the user prompt and use user as the answer instead.
Causes boot(8) to start factotum with the –p option, so that it
can be debugged.
Causes boot(8) to start factotum with the given options, which
must be a single word (i.e., contain no whitespace).
When booting from a local fossil server backed by a local or remote
venti server, this variable specifies how to establish the connection
to the venti server. See boot(8) for more.
This names the file holding the disk partition for the cache file
system, cfs(4). Extending the bootargs example, one would write
This deprecated variable was used to specify the disk used by
the cache file system and other disk–resident services. It is superseded
by bootargs and cfs.
This defines the partition table 9load(8) will examine to find
disk partitioning information. By default, a partition table in
a Plan 9 partition is consulted; if no such table is found, an
old–Plan 9 partition table on the next–to–last or last sector of
the disk is consulted. A value of new consults only the first
table, old only
These specify the IP address of the file and authentication server
to use when mounting a network–provided root file system. They
are used only if the addresses cannot be determined via DHCP.
The PC kernel switches the processor to 16–bit real mode to run
BIOS interrupts, for example to find the memory map or to enable
VESA. This variable disables such switches.
When available, the PC kernel uses the BIOS E820 memory map to
size memory. This variable disables the scan.
A space–seperated list of 3–tuples of ACPI memory type, start address
and end address generated at runtime by 9load and iplpxe.
This defines the maximum physical address that the system will
scan when sizing memory. By default the PC operating system will
scan up to 3.75 gigabytes (0xF0000000, the base of kernel virtual
address space), but setting *maxmem will limit the scan. *maxmem
must be less than 3.75 gigabytes. This variable is
not consulted if using the E820 memory map.
This defines the percentage of available memory reserved for the
kernel allocation pool. The remainder is left for user processes.
The default percent is 30 on CPU servers, 60 on terminals with
less than 16MB of memory, and 40 on terminals with memories of
16MB or more. Terminals use more kernel memory
because draw(3) maintains its graphic images in kernel memory.
This deprecated option is rarely necessary in newer kernels.
If machine check exceptions are supported by the processor, then
they are enabled by default. Setting this variable to 1 causes
them to be disabled even when available.
A multiprocessor machine will enable all processors by default.
Setting *nomp restricts the kernel to starting only one processor
and using the traditional interrupt controller.
Setting *ncpu restricts the kernel to starting at most cpus processors.
Limits the maximum bus number probed on a PCI bus (default 255).
This, and *pcimaxdno below are rarely used and only on troublesome
or suspect hardware.
Limits the maximum device number probed on a PCI bus (default
Disable pci routing during boot. May solve interrupt routing problems
on certain machines.
Disable printing a stack dump on panic. Useful if there is only
a limited cga screen available, otherwise the textual information
about the panic may scroll off.
Specifies a list of ranges of I/O ports to exclude from use by
drivers. Ranges are inclusive on both ends and separated by commas.
Specifies a list of ranges of UMB to exclude from use by drivers.
Ranges are inclusive on both ends and separated by commas. For
This enables the ``advanced power management'' interface as described
in apm(3) and apm(8). The main feature of the interface is the
ability to watch battery life (see stats(8)). It is not on by
default because it causes problems on some laptops.
These are used not by the kernel but by termrc (see cpurc(8))
when starting vga(8).
This is used to specify the screen blanking behavior of the MGA4xx
and Radeon video drivers. Values are standby, suspend, and off.
The first two specify differing levels of power saving; the third
turns the monitor off completely.
A plan9.ini file may contain multiple configurations, each within
a block beginning with a line
A special block with the tag menu gives a list of blocks from
which the user may interactively select the contents of plan9.ini.
There may also be multiple blocks with the tag common which will
be included in all selections; if any lines appear in plan9.ini
before the first block, they are treated as a common
Within the menu block the following configuration lines are allowed:
The block identified by tag will appear in the presented menu.
The menu entry will consist of the tag unless the optional description
Identifies a default block to be given in the menu selection prompt.
If the optional timeout is given (in seconds), the default block
will be selected if there is no user input within the timeout
menuconsole=value options[, baud]
In response to the menu being printed, the user is prompted to
select a menu item from the list. If the numeric response is followed
by a p, the selected configuration is printed and the menu presented
Selects a serial console upon which to present the menu as no
console options will have been processed yet (the plan9.ini contents
are still to be decided...). The depricated baud option is accepted
to assist older configurations.
is prefixed to the selected configuration as an aid to user–level