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="<options>"' 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=<mask>,allowed_drive_mask Obsolete. Use the floppy=<drive>,<type>,cmos option instead floppy=all_drives Obsolete. Use the floppy=<drive>,<type>,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=<address>,two_fdc Tells the floppy driver that you have two floppy controllers. The second floppy controller is assumed to be at <address>. 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=<threshold>,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=<drive>,<type>,cmos Sets the CMOS type of <drive> to <type>. 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: 0 - Use the value of the physical CMOS 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<kernel-version>-<day><month>.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<kernel-version>-<day><month>.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