This section lists all the boot args associated with standard MFM/RLL, ST-506, XT, and IDE disk drive devices. Note that both the IDE and the generic ST-506 HD driver both accept the `hd=' option.
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 one of:
`hda=', `hdb=', `hdc=', or `hdd='.
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, b, c, d) sequence.
For the following discussions, the `hd=' option will be cited
for brevity. Please consult the file README.ide in the
linux/drivers/block directory if more information is
required.
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 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. If you only have up to two drives, both on the primary interface, then you don't need to use this 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.
If a particular drive (e.g. old IDE drive) has problems that are a result of being probed, this option can be used to disable the probe. An example usage could be:
hdb=noprobe hdb=1166,7,17
which would disable the probe, but still specify the drive geometry so that it would be registered as a valid block device, and hence useable.
Some drives apparently have the WRERR_STAT bit stuck on permanently. This enables a work-around for these broken devices.
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.
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=', `hdb=' and so on are not valid here. The format is as follows:
hd=cyls,heads,sects
If there are two disks installed, the above is repeated with the geometry parameters of the second disk.
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. The probe code for these cards looks for an installed BIOS, and if none is present, the probe will not find your card. Or, if the signature string of your BIOS is not recognised then it will also not be found. In either case, you will then have to use a boot arg of the form:
xd=type,irq,iobase,dma_chan
The type value specifies the particular manufacturer of the
card, and are as follows: 0=generic; 1=DTC; 2,3,4=Western Digital,
5,6,7=Seagate; 8=OMTI. The only difference between multiple types
from the same manufacturer is the BIOS string used for detection,
which is not used if the type is specified.
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:
xd=2,5,0x320,3