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This Readme file describes the floppy driver.

FAQ list:

=========

 A FAQ list may be found in the fdutils package (see below), and also

at ftp.imag.fr:pub/Linux/ZLIBC/floppy/FAQ

Lilo config options (Thinkpad users, read this)

===============================================

 The floppy driver is configured using the 'floppy=' option in

lilo. This option can be typed at the boot prompt, or entered in the

lilo configuration file.

 Example: If your kernel is called linux-pre2.0.9, type the following line

at the lilo boot prompt (if you have a thinkpad):

 linux-pre2.0.9 floppy=thinkpad

You may also enter the following line in /etc/lilo.conf, in the description

of linux-pre2.0.9:

 append = "floppy=thinkpad"

 Several floppy related options may be given, example:

 linux-pre2.0.9 floppy=daring floppy=two_fdc

 append = "floppy=daring floppy=two_fdc"

 If you give options both in the lilo config file and on the boot

prompt, the option strings of both places are concatenated, the boot

prompt options coming last. That's why there are also options to

restore the default behavior.

 If you use the floppy driver as a module, use the following syntax:

 insmod floppy 'floppy=""'

Example:

 insmod floppy 'floppy="daring two_fdc"'

 Note that in this case 'floppy=' should only be typed out once, and

not once for each option. You need at least modules-1.3.57 for this

method.  However, the older environment variable based syntax is still

available:

(sh syntax): floppy="daring two_fdc" insmod floppy

(csh syntax): setenv floppy "daring two_fdc" ; insmod floppy

 Some versions of insmod are buggy in one way or another. If you have

any problems (options not being passed correctly, segfaults during

insmod), first check whether there is a more recent version. If there

isn't, use the old method using environment variables.

 The floppy related options include:

 floppy=,allowed_drive_mask

        Obsolete. Use the floppy=,,cmos option instead

 floppy=all_drives

        Obsolete. Use the floppy=,,cmos option instead

 floppy=asus_pci

        Sets the bit mask 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

 floppy=
,two_fdc

        Tells the floppy driver that you have two floppy controllers. The

        second floppy controller is assumed to be at 
. This

        option is not needed if the second controller is at address

        0x370, and if you use the 'cmos' option

 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=omnibook

 floppy=nodma

        Tells the floppy driver not to use Dma for data transfers.

        This is needed on HP Omnibooks, which don't have a workable

        DMA channel for the floppy driver. This option is also useful

        if you frequently get "Unable to allocate DMA memory" messages.

        Indeed, dma memory needs to be continuous in physical, and is

        thus harder to find, whereas non-dma buffers may be allocated

        in virtual memory. However, I advise against this if you have

        an FDC without a FIFO (8272A or 82072). 82072A and later are

        OK. You also need at least a 486 to use nodma.

        If you use nodma mode, I suggest you also set the FIFO

        threshold to 10 or lower, in order to limit the number of data

        transfer interrupts.

 floppy=dma

        Tells the floppy driver that a workable DMA channel is available

        (the default).

floppy=nofifo

        Disables the FIFO entirely. This is needed if you get "Bus

        master arbitration error" messages from your ethernet card (or

        from other devices) while accessing the floppy.

floppy=fifo

        Enables the FIFO (default)

 floppy=,fifo_depth

        Sets the FIFO threshold. This is mostly relevant in DMA

        mode. If this is higher, the floppy driver tolerates more

        interrupt latency, but it triggers more interrupts (i.e. it

        imposes more load on the rest of the system). If this is

        lower, the interrupt latency should be lower too (faster

        processor). The benefit of a lower threshold is less

        interrupts.

        To tune the fifo threshold, switch on over/underrun messages

        using 'floppycontrol --messages'. Then access a floppy

        disk. If you get a huge amount of "Over/Underrun - retrying"

        messages, then the fifo threshold is too low. Try with a

        higher value, until you only get an occasional Over/Underrun.

        It is a good idea to compile the floppy driver as a module

        when doing this tuning. Indeed, it allows to try different

        fifo values without rebooting the machine for each test. Note

        that you need to do 'floppycontrol --messages' every time you

        re-insert the module.

        Usually, tuning the fifo threshold should not be needed, as

        the default (0xa) is reasonable.

 floppy=,,cmos

        Sets the CMOS type of  to . This is mandatory 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. The CMOS types are:

                1 - 5 1/4 DD

                2 - 5 1/4 HD

                3 - 3 1/2 DD

                4 - 3 1/2 HD

                5 - 3 1/2 ED

                6 - 3 1/2 ED

               16 - unknown or not installed

        (Note: there are two valid types for ED drives. This is because 5 was

        initially chosen to represent floppy *tapes*, and 6 for ED drives.

        AMI ignored this, and used 5 for ED drives. That's why the floppy

        driver handles both)

 floppy=unexpected_interrupts

        Print a warning message when an unexpected interrupt is received

        (default behavior)

 floppy=no_unexpected_interrupts

 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.)

Supporting utilities and additional documentation:

==================================================

 Additional parameters of the floppy driver can be configured at run

time.  Utilities which do this can be found in the fdutils

package. This package also contains a new version of mtools which

allows to access high capacity disks (up to 1992K on a high density 3

1/2 disk!). It also contains additional documentation about the floppy

driver. It can be found at:

 ftp.imag.fr:pub/Linux/ZLIBC/fdutils/fdutils-4.1.src.tar.gz

 sunsite.unc.edu:/pub/Linux/system/Misc/fdutils-4.1.src.tar.gz

 tsx-11.mit.edu:/pub/linux/sources/sbin/fdutils-4.1.src.tar.gz

 Alpha patches to these utilities are at:

 ftp.imag.fr:pub/Linux/ZLIBC/fdutils/ALPHA

 All patches contained in this directory are directly against the base

version, i.e. DON'T APPLY THEM ON TOP OF EACH OTHER. Only apply the

most recent one.

Alpha patches for the floppy driver:

====================================

 You may find ALPHA patches of the driver itself in

ftp.imag.fr:pub/Linux/ZLIBC/floppy/ALPHA. These patches are named

fdp-.diff.gz

 WARNING: These _are_ ALPHA, and may introduce new problems! Some

problems may only show up on certain hardware, or when trying weirdo

things. So don't be misled by people claiming they are stable and

should really be BETA. What works for one person, may not work for

somebody else at all. This directory contains a RELEASES file

describing the features of some of these patches.

 If after some testing these patches prove to be sufficiently stable,

they'll move into ftp.imag.fr:pub/Linux/ZLIBC/floppy/BETA.

 You may find quick&dirty fixes to the driver in

ftp.imag.fr:pub/Linux/ZLIBC/QDF. These patches are named

fdp-.diff

 These patches fix only the most obvious problems, or provide trivial

enhancements. The main objective is to keep these patches small and

local, in order to keep the probability of introducing new problems as

small as possible. However, they may not attack the root of the

problem but only cure the symptoms. This directory contains a RELEASES

file describing the features of these patches.

 The ALPHA, BETA and QDF directories are removed, and replaced by a

README file when they get empty due to integration of the patches into

the stock kernel. You may still find patches to old kernels in

ftp.imag.fr:pub/Linux/ZLIBC/obsolete

Reporting problems about the floppy driver

==========================================

 If you have a question or a bug report about the floppy driver, mail

me at Alain.Knaff@imag.fr. If you post to the news, use preferably one

of the groups comp.os.linux.help (for questions) or

comp.os.linux.hardware (for bug reports). As the volume in these

groups is rather high, be sure to include the word "floppy" (or

"FLOPPY") in the subject line.

 Be sure to read the FAQ before mailing/posting any bug reports!

 Alain