[Linux manuál]
When the kernel is booted directly by the BIOS (say from a floppy to which you
copied a kernel using `cp zImage /dev/fd0'), you have no opportunity to
specify any parameters. So, in order to take advantage of this possibility you
have to use software that is able to pass parameters, like LILO or loadlin.
For a few parameters one can also modify the kernel image itself, using rdev,
see rdev(8) for further details.
The LILO program (LInux LOader) written by Werner Almesberger is the most
commonly used. It has the ability to boot various kernels, and stores the
configuration information in a plain text file. (See lilo(8) and
lilo.conf(5).) LILO can boot DOS, OS/2, Linux, FreeBSD, UnixWare, etc.,
and is quite flexible.
The other commonly used Linux loader is `LoadLin' which is a DOS program that
has the capability to launch a Linux kernel from the DOS prompt (with
boot-args) assuming that certain resources are available. This is good for
people that want to launch Linux from DOS.
It is also very useful if you have certain hardware which relies on the supplied
DOS driver to put the hardware into a known state. A common example is
`SoundBlaster Compatible' sound cards that require the DOS driver to twiddle a
few mystical registers to put the card into a SB compatible mode. Booting DOS
with the supplied driver, and then loading Linux from the DOS prompt with
loadlin avoids the reset of the card that happens if one rebooted instead.
Most of the sorting goes on in linux/init/main.c. First, the kernel checks to
see if the argument is any of the special arguments `root=', `nfsroot=',
`nfsaddrs=', `ro', `rw', `debug' or `init'. The meaning of these special
arguments is described below.
Then it walks a list of setup functions (contained in the bootsetups array) to
see if the specified argument string (such as `foo') has been associated with
a setup function (`foo_setup()') for a particular device or part of the
kernel. If you passed the kernel the line foo=3,4,5,6 then the kernel would
search the bootsetups array to see if `foo' was registered. If it was, then it
would call the setup function associated with `foo' (foo_setup()) and hand it
the arguments 3, 4, 5 and 6 as given on the kernel command line.
Anything of the form `foo=bar' that is not accepted as a setup function as
described above is then interpreted as an environment variable to be set. A
(useless?) example would be to use `TERM=vt100' as a boot argument.
Any remaining arguments that were not picked up by the kernel and were not
interpreted as environment variables are then passed onto process one, which
is usually the init program. The most common argument that is passed to the
init process is the word `single' which instructs init to boot the computer in
single user mode, and not launch all the usual daemons. Check the manual page
for the version of init installed on your system to see what arguments it
accepts.
The root device can be specified symbolically or numerically. A symbolic
specification has the form /dev/XXYN, where XX designates the device type
(`hd' for ST-506 compatible hard disk, with Y in `a'-`d'; `sd' for SCSI
compatible disk, with Y in `a'-`e'; `ad' for Atari ACSI disk, with Y in
`a'-`e', `ez' for a Syquest EZ135 parallel port removable drive, with Y=`a',
`xd' for XT compatible disk, with Y either `a' or `b'; `fd' for floppy disk,
with Y the floppy drive number - fd0 would be the DOS `A:' drive, and fd1
would be `B:'), Y the driver letter or number, and N the number (in decimal)
of the partition on this device (absent in the case of floppies). Recent
kernels allow many other types, mostly for CD-ROMs: nfs, ram, scd, mcd,
cdu535, aztcd, cm206cd, gscd, sbpcd, sonycd, bpcd. (The type nfs specifies a
net boot; ram refers to a ram disk.)
Note that this has nothing to do with the designation of these devices on your
file system. The `/dev/' part is purely conventional.
The more awkward and less portable numeric specification of the above possible
root devices in major/minor format is also accepted. (E.g., /dev/sda3 is major
8, minor 3, so you could use `root=0x803' as an alternative.)
The `rw' option tells the kernel to mount the root filesystem read/write. This
is the default.
The choice between read-only and read/write can also be set using
rdev(8).
The reserve boot-time argument specifies an I/O port region that shouldn't be
probed. A device driver will not probe a reserved region, unless another boot
argument explicitly specifies that it do so.
For example, the boot line
``The kernel will accept any `mem=xx' parameter you give it, and if it turns out
that you lied to it, it will crash horribly sooner or later. The parameter
indicates the highest addressable RAM address, so `mem=0x1000000' means you
have 16MB of memory, for example. For a 96MB machine this would be
`mem=0x6000000'.
NOTE NOTE NOTE: some machines might use the top of memory for BIOS cacheing or
whatever, so you might not actually have up to the full 96MB addressable. The
reverse is also true: some chipsets will map the physical memory that is
covered by the BIOS area into the area just past the top of memory, so the
top-of-mem might actually be 96MB + 384kB for example. If you tell linux that
it has more memory than it actually does have, bad things will happen: maybe
not at once, but surely eventually.''
In Linux 1.3.48, ramdisk handling was changed drastically. Earlier, the memory
was allocated statically, and there was a `ramdisk=N' parameter to tell its
size. (This could also be set in the kernel image at compile time, or by use
of rdev(8).) These days ram disks use the buffer cache, and grow
dynamically. For a lot of information (e.g., how to use rdev(8) in
conjunction with the new ramdisk setup), see
/usr/src/linux/Documentation/ramdisk.txt.
There are four parameters, two boolean and two integral.
For a detailed description of the initrd feature, see
/usr/src/linux/Documentation/initrd.txt.
The `noinitrd' option tells the kernel that although it was compiled for
operation with initrd, it should not go through the above steps, but leave the
initrd data under /dev/initrd. (This device can be used only once - the
data is freed as soon as the last process that used it has closed
/dev/initrd.)
iobase -- the first I/O port that the SCSI host occupies. These are
specified in hexidecimal notation, and usually lie in the range from 0x200 to
0x3ff.
irq -- the hardware interrupt that the card is configured to use. Valid
values will be dependent on the card in question, but will usually be 5, 7, 9,
10, 11, 12, and 15. The other values are usually used for common peripherals
like IDE hard disks, floppies, serial ports, etc.
scsi-id -- the ID that the host adapter uses to identify itself on the
SCSI bus. Only some host adapters allow you to change this value, as most have
it permanently specified internally. The usual default value is 7, but the
Seagate and Future Domain TMC-950 boards use 6.
parity -- whether the SCSI host adapter expects the attached devices to
supply a parity value with all information exchanges. Specifying a one
indicates parity checking is enabled, and a zero disables parity checking.
Again, not all adapters will support selection of parity behaviour as a boot
argument.
Some poorly designed SCSI devices cannot handle being probed for LUNs not equal
to zero. Therefore, if the compile time flag CONFIG_SCSI_MULTI_LUN is not set,
newer kernels will by default only probe LUN zero.
To specify the number of probed LUNs at boot, one enters `max_scsi_luns=n' as a
boot arg, where n is a number between one and eight. To avoid problems as
described above, one would use n=1 to avoid upsetting such broken devices.
The probe code for these SCSI hosts looks for an installed BIOS, and if none is
present, the probe will not find your card. Then you will have to use a boot
arg of the form:
All the parameters are as described at the top of this section, and the
reconnect value will allow device disconnect/reconnect if a non-zero
value is used. An example usage is as follows:
The buson, busoff values refer to the number of microseconds that
the card dominates the ISA bus. The defaults are 11us on, and 4us off, so that
other cards (such as an ISA LANCE Ethernet card) have a chance to get access
to the ISA bus.
The dmaspeed value refers to the rate (in MB/s) at which the DMA (Direct
Memory Access) transfers proceed. The default is 5MB/s. Newer revision cards
allow you to select this value as part of the soft-configuration, older cards
use jumpers. You can use values up to 10MB/s assuming that your motherboard is
capable of handling it. Experiment with caution if using values over 5MB/s.
The parameters N1-N5 are integers. The parameters S1,... are strings. N1 is the
I/O Address at which the Host Adapter is located. N2 is the Tagged Queue Depth
to use for Target Devices that support Tagged Queuing. N3 is the Bus Settle
Time in seconds. This is the amount of time to wait between a Host Adapter
Hard Reset which initiates a SCSI Bus Reset and issuing any SCSI Commands. N4
is the Local Options (for one Host Adapter). N5 is the Global Options (for all
Host Adapters).
The string options are used to provide control over Tagged Queuing (TQ:Default,
TQ:Enable, TQ:Disable, TQ:<Per-Target-Spec>), over Error Recovery
(ER:Default, ER:HardReset, ER:BusDeviceReset, ER:None,
ER:<Per-Target-Spec>), and over Host Adapter Probing (NoProbe,
NoProbeISA, NoSortPCI).
Non-drive specific options are specified with the prefix `hd='. Note that using
a drive specific prefix for a non-drive specific option will still work, and
the option will just be applied as expected.
Also note that `hd=' can be used to refer to the next unspecified drive in the
(a, ..., h) sequence. For the following discussions, the `hd=' option will be
cited for brevity. See the file README.ide in linux/drivers/block for more
details.
The xd_setup() function does no checking on the values, and assumes that you
entered all four values. Don't disappoint it. Here is an example usage for a
WD1002 controller with the BIOS disabled/removed, using the `default' XT
controller parameters:
The is_pas_card should be entered as `PAS' if using a Pro Audio Spectrum
card, and otherwise it should not be specified at all.
The most common use of this parameter is to force probing for a second
ethercard, as the default is to only probe for one. This can be accomplished
with a simple:
The Ethernet-HowTo has extensive documentation on using multiple cards and on
the card/driver specific implementation of the param_n values where used.
Interested readers should refer to the section in that document on their
particular card.
T - device type: 1=FM, 2=SB, 3=PAS, 4=GUS, 5=MPU401, 6=SB16, 7=SB16-MPU401
aaa - I/O address in hex.
I - interrupt line in hex (i.e 10=a, 11=b, ...)
d - DMA channel.
As you can see it gets pretty messy, and you are better off to compile in your
own personal values as recommended. Using a boot arg of `sound=0' will disable
the sound driver entirely.
The format of the argument is multiple port names. For example, lp=none,parport0
would use the first parallel port for lp1, and disable lp0. To disable the
printer driver entirely, one can use lp=0.
bootparam: Úvod do parametrů zaváděcího času jádra systému Linux
Originální popis anglicky: bootparam - Introduction to boot time parameters of the Linux kernelPOPIS / INSTRUKCE
The Linux kernel accepts certain `command line options' or `boot time parameters' at the moment it is started. In general this is used to supply the kernel with information about hardware parameters that the kernel would not be able to determine on its own, or to avoid/override the values that the kernel would otherwise detect.THE ARGUMENT LIST
The kernel command line is parsed into a list of strings (boot arguments) separated by spaces. Most of the boot args take the form of:- name[=value_1][,value_2]...[,value_10]
GENERAL NON-DEVICE SPECIFIC BOOT ARGS
`init=...'
This sets the initial command to be executed by the kernel. If this is not set, or cannot be found, the kernel will try /etc/init, then /bin/init, then /sbin/init, then /bin/sh and panic if all of this fails.`nfsaddrs=...'
This sets the nfs boot address to the given string. This boot address is used in case of a net boot.`nfsroot=...'
This sets the nfs root name to the given string. If this string does not begin with '/' or ',' or a digit, then it is prefixed by `/tftpboot/'. This root name is used in case of a net boot.`no387'
(Only when CONFIG_BUGi386 is defined.) Some i387 coprocessor chips have bugs that show up when used in 32 bit protected mode. For example, some of the early ULSI-387 chips would cause solid lockups while performing floating point calculations. Using the `no387' boot arg causes Linux to ignore the maths coprocessor even if you have one. Of course you must then have your kernel compiled with math emulation support!`no-hlt'
(Only when CONFIG_BUGi386 is defined.) Some of the early i486DX-100 chips have a problem with the `hlt' instruction, in that they can't reliably return to operating mode after this instruction is used. Using the `no-hlt' instruction tells Linux to just run an infinite loop when there is nothing else to do, and to not halt the CPU. This allows people with these broken chips to use Linux.`root=...'
This argument tells the kernel what device is to be used as the root filesystem while booting. The default of this setting is determined at compile time, and usually is the value of the root device of the system that the kernel was built on. To override this value, and select the second floppy drive as the root device, one would use `root=/dev/fd1'. (The root device can also be set using rdev(8).)`ro' and `rw'
The `ro' option tells the kernel to mount the root filesystem as `readonly' so that filesystem consistency check programs (fsck) can do their work on a quiescent file system. No processes can write to files on the filesystem in question until it is `remounted' as read/write capable, e.g., by `mount -w -n -o remount /'. (See also mount(8).)`reserve=...'
This is used to protect I/O port regions from probes. The form of the command is:- reserve=iobase,extent[,iobase,extent]...
- reserve=0x300,32 blah=0x300
`mem=...'
The BIOS call defined in the PC specification that returns the amount of installed memory was only designed to be able to report up to 64MB. Linux uses this BIOS call at boot to determine how much memory is installed. If you have more than 64MB of RAM installed, you can use this boot arg to tell Linux how much memory you have. The value is in decimal or hexadecimal (prefix 0x), and the suffixes `k' (times 1024) or `M' (times 1048576) can be used. Here is a quote from Linus on usage of the `mem=' parameter.`panic=N'
By default the kernel will not reboot after a panic, but this option will cause a kernel reboot after N seconds (if N > 0). This panic timeout can also be set by "echo N > /proc/sys/kernel/panic".`reboot=[warm|cold][,[bios|hard]]'
(Only when CONFIG_BUGi386 is defined.) Since 2.0.22 a reboot is by default a cold reboot. One asks for the old default with `reboot=warm'. (A cold reboot may be required to reset certain hardware, but might destroy not yet written data in a disk cache. A warm reboot may be faster.) By default a reboot is hard, by asking the keyboard controller to pulse the reset line low, but there is at least one type of motherboard where that doesn't work. The option `reboot=bios' will instead jump through the BIOS.`nosmp' and `maxcpus=N'
(Only when __SMP__ is defined.) A command-line option of `nosmp' or `maxcpus=0' will disable SMP activation entirely; an option `maxcpus=N' limits the maximum number of CPUs activated in SMP mode to N.BOOT ARGUMENTS FOR USE BY KERNEL DEVELOPERS
`debug'
Kernel messages are handed off to the kernel log daemon klogd so that they may be logged to disk. Messages with a priority above console_loglevel are also printed on the console. (For these levels, see <linux/kernel.h>.) By default this variable is set to log anything more important than debug messages. This boot argument will cause the kernel to also print the messages of DEBUG priority. The console loglevel can also be set at run time via an option to klogd. See klogd(8).`profile=N'
It is possible to enable a kernel profiling function, if one wishes to find out where the kernel is spending its CPU cycles. Profiling is enabled by setting the variable prof_shift to a nonzero value. This is done either by specifying CONFIG_PROFILE at compile time, or by giving the `profile=' option. Now the value that prof_shift gets will be N, when given, or CONFIG_PROFILE_SHIFT, when that is given, or 2, the default. The significance of this variable is that it gives the granularity of the profiling: each clock tick, if the system was executing kernel code, a counter is incremented:- profile[address >> prof_shift]++;
`swap=N1,N2,N3,N4,N5,N6,N7,N8'
Set the eight parameters max_page_age, page_advance, page_decline, page_initial_age, age_cluster_fract, age_cluster_min, pageout_weight, bufferout_weight that control the kernel swap algorithm. For kernel tuners only.`buff=N1,N2,N3,N4,N5,N6'
Set the six parameters max_buff_age, buff_advance, buff_decline, buff_initial_age, bufferout_weight, buffermem_grace that control kernel buffer memory management. For kernel tuners only.BOOT ARGUMENTS FOR RAMDISK USE
(Only if the kernel was compiled with CONFIG_BLK_DEV_RAM.) In general it is a bad idea to use a ramdisk under Linux - the system will use available memory more efficiently itself. But while booting (or while constructing boot floppies) it is often useful to load the floppy contents into a ramdisk. One might also have a system in which first some modules (for filesystem or hardware) must be loaded before the main disk can be accessed.`load_ramdisk=N'
If N=1, do load a ramdisk. If N=0, do not load a ramdisk. (This is the default.)`prompt_ramdisk=N'
If N=1, do prompt for insertion of the floppy. (This is the default.) If N=0, do not prompt. (Thus, this parameter is never needed.)`ramdisk_size=N' or (obsolete) `ramdisk=N'
Set the maximal size of the ramdisk(s) to N kB. The default is 4096 (4 MB).`ramdisk_start=N'
Sets the starting block number (the offset on the floppy where the ramdisk starts) to N. This is needed in case the ramdisk follows a kernel image.`noinitrd'
(Only if the kernel was compiled with CONFIG_BLK_DEV_RAM and CONFIG_BLK_DEV_INITRD.) These days it is possible to compile the kernel to use initrd. When this feature is enabled, the boot process will load the kernel and an initial ramdisk; then the kernel converts initrd into a "normal" ramdisk, which is mounted read-write as root device; then /linuxrc is executed; afterwards the "real" root file system is mounted, and the initrd filesystem is moved over to /initrd; finally the usual boot sequence (e.g. invocation of /sbin/init) is performed.BOOT ARGUMENTS FOR SCSI DEVICES
General notation for this section:`max_scsi_luns=...'
A SCSI device can have a number of `sub-devices' contained within itself. The most common example is one of the new SCSI CD-ROMs that handle more than one disk at a time. Each CD is addressed as a `Logical Unit Number' (LUN) of that particular device. But most devices, such as hard disks, tape drives and such are only one device, and will be assigned to LUN zero.SCSI tape configuration
Some boot time configuration of the SCSI tape driver can be achieved by using the following:- st=buf_size[,write_threshold[,max_bufs]]
- st=32,30,2
Adaptec aha151x, aha152x, aic6260, aic6360, SB16-SCSI configuration
The aha numbers refer to cards and the aic numbers refer to the actual SCSI chip on these type of cards, including the Soundblaster-16 SCSI.- aha152x=iobase[,irq[,scsi-id[,reconnect[,parity]]]]
- aha152x=0x340,11,7,1
Adaptec aha154x configuration
The aha1542 series cards have an i82077 floppy controller onboard, while the aha1540 series cards do not. These are busmastering cards, and have parameters to set the ``fairness'' that is used to share the bus with other devices. The boot arg looks like the following.- aha1542=iobase[,buson,busoff[,dmaspeed]]
Adaptec aha274x, aha284x, aic7xxx configuration
These boards can accept an argument of the form:- aic7xxx=extended,no_reset
AdvanSys SCSI Hosts configuration (`advansys=')
The AdvanSys driver can accept up to four i/o addresses that will be probed for an AdvanSys SCSI card. Note that these values (if used) do not effect EISA or PCI probing in any way. They are only used for probing ISA and VLB cards. In addition, if the driver has been compiled with debugging enabled, the level of debugging output can be set by adding an 0xdeb[0-f] parameter. The 0-f allows setting the level of the debugging messages to any of 16 levels of verbosity.AM53C974
- AM53C974=host-scsi-id,target-scsi-id,max-rate,max-offset
BusLogic SCSI Hosts configuration (`BusLogic=')
- BusLogic=N1,N2,N3,N4,N5,S1,S2,...
EATA/DMA configuration
The default list of i/o ports to be probed can be changed by- eata=iobase,iobase,....
Future Domain TMC-16x0 configuration
- fdomain=iobase,irq[,adapter_id]
Great Valley Products (GVP) SCSI controller configuration
- gvp11=dma_transfer_bitmask
Future Domain TMC-8xx, TMC-950 configuration
- tmc8xx=mem_base,irq
IN2000 configuration
- in2000=S
NCR5380 and NCR53C400 configuration
The boot arg is of the form- ncr5380=iobase,irq,dma
- ncr53c400=iobase,irq
NCR53C8xx configuration
- ncr53c8xx=S
NCR53c406a configuration
- ncr53c406a=iobase[,irq[,fastpio]]
Pro Audio Spectrum configuration
The PAS16 uses a NC5380 SCSI chip, and newer models support jumperless configuration. The boot arg is of the form:- pas16=iobase,irq
Seagate ST-0x configuration
If your card is not detected at boot time, you will then have to use a boot arg of the form:- st0x=mem_base,irq
Trantor T128 configuration
These cards are also based on the NCR5380 chip, and accept the following options:- t128=mem_base,irq
UltraStor 14F/34F configuration
The default list of i/o ports to be probed can be changed by- eata=iobase,iobase,....
WD7000 configuration
- wd7000=irq,dma,iobase
Commodore Amiga A2091/590 SCSI controller configuration
- wd33c93=S
HARD DISKS
IDE Disk/CD-ROM Driver Parameters
The IDE driver accepts a number of parameters, which range from disk geometry specifications, to support for broken controller chips. Drive specific options are specified by using `hdX=' with X in `a'-`h'.The `hd=cyls,heads,sects[,wpcom[,irq]]' options
These options are used to specify the physical geometry of the disk. Only the first three values are required. The cylinder/head/sectors values will be those used by fdisk. The write precompensation value is ignored for IDE disks. The IRQ value specified will be the IRQ used for the interface that the drive resides on, and is not really a drive specific parameter.The `hd=serialize' option
The dual IDE interface CMD-640 chip is broken as designed such that when drives on the secondary interface are used at the same time as drives on the primary interface, it will corrupt your data. Using this option tells the driver to make sure that both interfaces are never used at the same time.The `hd=dtc2278' option
This option tells the driver that you have a DTC-2278D IDE interface. The driver then tries to do DTC specific operations to enable the second interface and to enable faster transfer modes.The `hd=noprobe' option
Do not probe for this drive. For example,- hdb=noprobe hdb=1166,7,17
The `hd=nowerr' option
Some drives apparently have the WRERR_STAT bit stuck on permanently. This enables a work-around for these broken devices.The `hd=cdrom' option
This tells the IDE driver that there is an ATAPI compatible CD-ROM attached in place of a normal IDE hard disk. In most cases the CD-ROM is identified automatically, but if it isn't then this may help.Standard ST-506 Disk Driver Options (`hd=')
The standard disk driver can accept geometry arguments for the disks similar to the IDE driver. Note however that it only expects three values (C/H/S) -- any more or any less and it will silently ignore you. Also, it only accepts `hd=' as an argument, i.e. `hda=' and so on are not valid here. The format is as follows:- hd=cyls,heads,sects
XT Disk Driver Options (`xd=')
If you are unfortunate enough to be using one of these old 8 bit cards that move data at a whopping 125kB/s then here is the scoop. If the card is not recognised, you will have to use a boot arg of the form:- xd=type,irq,iobase,dma_chan
- xd=2,5,0x320,3
Syquest's EZ* removable disks
- ez=iobase[,irq[,rep[,nybble]]]
IBM MCA BUS DEVICES
See also /usr/src/linux/Documentation/mca.txt.PS/2 ESDI hard disks
It is possible to specify the desired geometry at boot time:- ed=cyls,heads,sectors.
- tp720=1.
IBM Microchannel SCSI Subsystem configuration
- ibmmcascsi=N
CD-ROMs (Non-SCSI/ATAPI/IDE)
The Aztech Interface
The syntax for this type of card is:- aztcd=iobase[,magic_number]
Parallel port CD-ROM drives
Syntax:- pcd.driveN=prt,pro,uni,mod,slv,dly
pcd.nice=nice
The CDU-31A and CDU-33A Sony Interface
This CD-ROM interface is found on some of the Pro Audio Spectrum sound cards, and other Sony supplied interface cards. The syntax is as follows:- cdu31a=iobase,[irq[,is_pas_card]]
The CDU-535 Sony Interface
The syntax for this CD-ROM interface is:- sonycd535=iobase[,irq]
The GoldStar Interface
The syntax for this CD-ROM interface is:- gscd=iobase
The ISP16 CD-ROM Interface
Syntax:- isp16=[iobase[,irq[,dma[,type]]]]
The Mitsumi Standard Interface
The syntax for this CD-ROM interface is:- mcd=iobase,[irq[,wait_value]]
The Mitsumi XA/MultiSession Interface
This is for the same hardware as above, but the driver has extended features. Syntax:- mcdx=iobase[,irq]
The Optics Storage Interface
The syntax for this type of card is:- optcd=iobase
The Phillips CM206 Interface
The syntax for this type of card is:- cm206=[iobase][,irq]
The Sanyo Interface
The syntax for this type of card is:- sjcd=iobase[,irq[,dma_channel]]
The SoundBlaster Pro Interface
The syntax for this type of card is:- sbpcd=iobase,type
ETHERNET DEVICES
Different drivers make use of different parameters, but they all at least share having an IRQ, an I/O port base value, and a name. In its most generic form, it looks something like this:- ether=irq,iobase[,param_1[,...param_8]],name
- ether=0,0,eth1
THE FLOPPY DISK DRIVER
There are many floppy driver options, and they are all listed in README.fd in linux/drivers/block. This information is taken directly from that file.floppy=mask,allowed_drive_mask
Sets the bitmask of allowed drives to mask. By default, only units 0 and 1 of each floppy controller are allowed. This is done because certain non-standard hardware (ASUS PCI motherboards) mess up the keyboard when accessing units 2 or 3. This option is somewhat obsoleted by the cmos option.floppy=all_drives
Sets the bitmask of allowed drives to all drives. Use this if you have more than two drives connected to a floppy controller.floppy=asus_pci
Sets the bitmask to allow only units 0 and 1. (The default)floppy=daring
Tells the floppy driver that you have a well behaved floppy controller. This allows more efficient and smoother operation, but may fail on certain controllers. This may speed up certain operations.floppy=0,daring
Tells the floppy driver that your floppy controller should be used with caution.floppy=one_fdc
Tells the floppy driver that you have only floppy controller (default)floppy=two_fdc or floppy=address,two_fdc
Tells the floppy driver that you have two floppy controllers. The second floppy controller is assumed to be at address. If address is not given, 0x370 is assumed.floppy=thinkpad
Tells the floppy driver that you have a Thinkpad. Thinkpads use an inverted convention for the disk change line.floppy=0,thinkpad
Tells the floppy driver that you don't have a Thinkpad.floppy=drive,type,cmos
Sets the cmos type of drive to type. Additionally, this drive is allowed in the bitmask. This is useful if you have more than two floppy drives (only two can be described in the physical cmos), or if your BIOS uses non-standard CMOS types. Setting the CMOS to 0 for the first two drives (default) makes the floppy driver read the physical cmos for those drives.floppy=unexpected_interrupts
Print a warning message when an unexpected interrupt is received (default behaviour)floppy=no_unexpected_interrupts or floppy=L40SX
Don't print a message when an unexpected interrupt is received. This is needed on IBM L40SX laptops in certain video modes. (There seems to be an interaction between video and floppy. The unexpected interrupts only affect performance, and can safely be ignored.)THE SOUND DRIVER
The sound driver can also accept boot args to override the compiled in values. This is not recommended, as it is rather complex. It is described in the Readme.Linux file, in linux/drivers/sound. It accepts a boot arg of the form:- sound=device1[,device2[,device3...[,device10]]]
ISDN DRIVERS
The ICN ISDN driver
Syntax:- icn=iobase,membase,icn_id1,icn_id2
The PCBIT ISDN driver
Syntax:- pcbit=membase1,irq1[,membase2,irq2]
The Teles ISDN driver
Syntax:- teles=iobase,irq,membase,protocol,teles_id
SERIAL PORT DRIVERS
The RISCom/8 Multiport Serial Driver (`riscom8=')
Syntax:- riscom=iobase1[,iobase2[,iobase3[,iobase4]]]
The DigiBoard Driver (`digi=')
If this option is used, it should have precisely six parameters. Syntax:- digi=status,type,altpin,numports,iobase,membase
- digi=E,PC/Xi,D,16,200,D0000
digi=1,0,0,16,0x200,851968
The Baycom Serial/Parallel Radio Modem
Syntax:- baycom=iobase,irq,modem
Soundcard radio modem driver
Syntax:- soundmodem=iobase,irq,dma[,dma2[,serio[,pario]]],0,mode
THE LINE PRINTER DRIVER
`lp='
Syntax:- lp=0
lp=autolp=resetlp=port[,port...]
WDT500/501 driver
Syntax:- wdt=io,irq